The document is an internship report summarizing Han Jin's three-month internship at Apex Europe B.V. in the Netherlands. It describes three projects conducted during the internship: 1) using laser engraving machines to clean inks from used anilox rolls without damaging the ceramic surface, 2) using laser post-melting of anilox rolls after engraving to replace finishing processes, and 3) investigating surface tension and roughness changes after laser treatment. The report provides details on the experiments conducted for each project, including testing different laser parameters and measurement of results. It also includes background context on flexographic printing and the role of anilox rolls in the printing process.
Nature provides many examples of efficient and effective designs that can inspire technological innovation. The document discusses several examples from nature like the lotus effect, spider silk, gecko feet, water striders, and water spiders that have unique properties and mechanisms. Researchers are studying these biological materials and structures to develop biomimetic materials and surfaces with applications like self-cleaning, strong composites, dry adhesives, low drag surfaces, and waterproof materials.
Superhydrophobic coatings can be created using various methods to produce rough surfaces that cause water to bead up into nearly spherical droplets rather than forming a continuous film. Such coatings have contact angles over 150 degrees, low slide angles under 10 degrees, and self-cleaning and non-sticking properties. They are being researched for applications like anti-fouling, anti-condensation, and anti-corrosion coatings through methods like layer-by-layer assembly, sol-gel processing, etching, and others. However, scaling these superhydrophobic surfaces from the lab to practical applications remains a technological challenge.
Selective Laser Melting versus Electron Beam MeltingCarsten Engel
This document summarizes research on additive manufacturing technologies for metal applications. It discusses Sirris, an organization that provides technology services to industry, and their expertise in additive manufacturing. Two key additive manufacturing technologies for metals are described - Electron Beam Melting (EBM) and Laser Beam Melting (LBM). EBM uses an electron beam to sinter metal powder in a vacuum environment, while LBM uses a laser beam under argon gas. Their differences in terms of process parameters, material properties, and advantages/disadvantages are summarized. Metallurgical analysis shows EBM produces a uniform fine-grained microstructure while LBM microstructure depends on build orientation. Mechanical properties are also compared between the two technologies.
The document discusses various nanofabrication techniques. Photolithography has limitations based on the optical diffraction limit. Electron beam lithography allows for higher resolution down to 5 nm but is slow and expensive. Soft lithography uses elastomeric stamps to transfer self-assembled monolayers in a parallel, low-cost manner via techniques like nanoimprint lithography and microcontact printing. Scanned probe techniques like atomic force microscopy and scanning tunneling microscopy can directly oxidize surfaces on the nanoscale.
Hideo Kodama invented stereolithography in the 1980s using ultraviolet light to cure photosensitive polymers layer by layer. Stereolithography (SLA) uses a UV laser to cure liquid resin into hardened plastic by photopolymerization, building a 3D model one thin layer at a time according to a 3D CAD file. The laser draws each layer, solidifying the resin, then the build platform rises and the next layer is drawn and cured on top of the previous. SLA produces strong prototypes suitable for machining and handles complex geometries with high detail, but is limited to photopolymer materials.
The document discusses various processing methods for ceramics, including the sol-gel process, slip casting, tape casting, extrusion, injection molding, and drying of green bodies. The sol-gel process involves the conversion of monomers into a colloidal solution that acts as a precursor for an integrated network or gel. Slip casting involves pouring a slurry into a plaster mold where the liquid is absorbed, depositing powder particles. Tape casting uses a doctor blade to spread a slurry onto a film at controlled thickness. Drying of green bodies occurs through boundary layer and pore processes, with shrinkage and defects occurring if not done uniformly.
Compression molding is a process where molten plastic is squeezed into a heated mold under high pressure. It is commonly used for thermosetting plastics like phenolics and urea-formaldehyde. The material is placed in an open mold and compressed until it hardens. This process is slower for thermoplastics which must be cooled before ejection. Compression molding produces parts with good surface finish and wastes little material.
this short ppt gives you a rough idea about the additive manufacturing process of stereolithography. This process is apart of 3d printing technologies around us. Also included is link to a video that will help you further.
Nature provides many examples of efficient and effective designs that can inspire technological innovation. The document discusses several examples from nature like the lotus effect, spider silk, gecko feet, water striders, and water spiders that have unique properties and mechanisms. Researchers are studying these biological materials and structures to develop biomimetic materials and surfaces with applications like self-cleaning, strong composites, dry adhesives, low drag surfaces, and waterproof materials.
Superhydrophobic coatings can be created using various methods to produce rough surfaces that cause water to bead up into nearly spherical droplets rather than forming a continuous film. Such coatings have contact angles over 150 degrees, low slide angles under 10 degrees, and self-cleaning and non-sticking properties. They are being researched for applications like anti-fouling, anti-condensation, and anti-corrosion coatings through methods like layer-by-layer assembly, sol-gel processing, etching, and others. However, scaling these superhydrophobic surfaces from the lab to practical applications remains a technological challenge.
Selective Laser Melting versus Electron Beam MeltingCarsten Engel
This document summarizes research on additive manufacturing technologies for metal applications. It discusses Sirris, an organization that provides technology services to industry, and their expertise in additive manufacturing. Two key additive manufacturing technologies for metals are described - Electron Beam Melting (EBM) and Laser Beam Melting (LBM). EBM uses an electron beam to sinter metal powder in a vacuum environment, while LBM uses a laser beam under argon gas. Their differences in terms of process parameters, material properties, and advantages/disadvantages are summarized. Metallurgical analysis shows EBM produces a uniform fine-grained microstructure while LBM microstructure depends on build orientation. Mechanical properties are also compared between the two technologies.
The document discusses various nanofabrication techniques. Photolithography has limitations based on the optical diffraction limit. Electron beam lithography allows for higher resolution down to 5 nm but is slow and expensive. Soft lithography uses elastomeric stamps to transfer self-assembled monolayers in a parallel, low-cost manner via techniques like nanoimprint lithography and microcontact printing. Scanned probe techniques like atomic force microscopy and scanning tunneling microscopy can directly oxidize surfaces on the nanoscale.
Hideo Kodama invented stereolithography in the 1980s using ultraviolet light to cure photosensitive polymers layer by layer. Stereolithography (SLA) uses a UV laser to cure liquid resin into hardened plastic by photopolymerization, building a 3D model one thin layer at a time according to a 3D CAD file. The laser draws each layer, solidifying the resin, then the build platform rises and the next layer is drawn and cured on top of the previous. SLA produces strong prototypes suitable for machining and handles complex geometries with high detail, but is limited to photopolymer materials.
The document discusses various processing methods for ceramics, including the sol-gel process, slip casting, tape casting, extrusion, injection molding, and drying of green bodies. The sol-gel process involves the conversion of monomers into a colloidal solution that acts as a precursor for an integrated network or gel. Slip casting involves pouring a slurry into a plaster mold where the liquid is absorbed, depositing powder particles. Tape casting uses a doctor blade to spread a slurry onto a film at controlled thickness. Drying of green bodies occurs through boundary layer and pore processes, with shrinkage and defects occurring if not done uniformly.
Compression molding is a process where molten plastic is squeezed into a heated mold under high pressure. It is commonly used for thermosetting plastics like phenolics and urea-formaldehyde. The material is placed in an open mold and compressed until it hardens. This process is slower for thermoplastics which must be cooled before ejection. Compression molding produces parts with good surface finish and wastes little material.
this short ppt gives you a rough idea about the additive manufacturing process of stereolithography. This process is apart of 3d printing technologies around us. Also included is link to a video that will help you further.
The document discusses calendering of paper and board. It provides details on:
1) The calendering process which involves pressing paper between rolls to smooth and gloss the surface. Key variables include nip impulse, web temperature and moisture.
2) Conventional calendering methods including machine, brush, soft and multi-nip calendering. Multi-nip calendering is needed for certain grades to achieve the desired smoothness and gloss.
3) New calendering methods like metal belt calendering which extends the dwell time under heat for better smoothness, coating layer and printability.
Optical Lithography, Key Enabling Technology for our Modern WorldReinhard Voelkel
In 1959, Richard P. Feynman initiated the Nano-age in his lecture “There’s plenty of room at the bottom”. Feynman also had a clear vision about computers and asked: ”Why can’t we make them very small, make them of little wires, little elements - and by little, I mean little. For instance, the wires should be 10 or 100 atoms in diameter, and the circuits should be a few thousand angstroms across.”
At the same time, Jean Hoerni from Fairchild Semiconductors tried to get his “planar process” to production. Hoerni’s planar process using silicon substrates, so-called “wafers”, revolutionized semiconductor manufacturing and was widely adapted by the industry. The great success of the planar wafer process is also much related with tremendous improvements in optical lithography over all the years. From the early age dominated by mask aligners to highly sophisticated steppers and scanners, lithography was the key enabling technology, allowing now – 50 years after Feynman’s vision – nanostructuring down to the atomic scale on 300mm planar wafers. The evolutionary development of optical lithography is reviewed along with a brief discussion of options for the future.
This document provides an overview of selective laser sintering (SLS), a 3D printing technique that uses a laser to fuse powdered material together layer by layer. It defines SLS, describes the basic multi-step process, and lists common input parameters and materials used. The document outlines key advantages like lack of support structures and fast printing, as well as limitations such as prints being brittle and prone to warping. A variety of applications are mentioned, including aerospace, medical, electronics, and automotive uses.
The document discusses ion beam etching, which is a physical dry etching process. Ion beam etching works by ionizing an inert gas like argon to create a plasma of positive ions and electrons. The ions are accelerated towards the target material, physically removing atoms from the surface through sputtering. Ion beam etching is highly directional and provides precise etching with minimal damage to the substrate. It can etch all materials and is used for applications requiring long lifetimes and precise specifications, like microelectronics and sensors.
This document provides an overview of metal drawing operations. It discusses the introduction to drawing, general operations like conditioning materials, process descriptions for shapes like rods/wires and tubes. It covers process requirements including tools, equipment, dies and load calculations. The key points are that metal drawing is a process that uses tensile forces to reduce cross-sectional area and elongate metal by pulling it through a die, important factors include the amount of reduction, speed, material properties and temperature. It can produce various shapes like rods, wires and tubes for different applications.
Printing Technology (Offset, Flexo, Gravure, Screen, Digital, 3D Printing) (Noncontact Printing ,Commercial Printing, Gravure Printing, Letterpress Printing, Offset Printing, Screen Printing, Offset Lithography, Lanography ,Flexography, Rotogravure, Digital Printing,3D Printing, 3D Printing Machinery, Blanket Cylinder, Plate Cylinder, Impression Cylinder, Web Offset Machines, printing press)
Printing is a process of producing copies of text and pictures. Modern technology is radically changing the way publications are printed, inventoried and distributed. There are a wide variety of technologies that are used to print stuff. The main industrial printing processes are: Offset Lithography, Flexography, Digital Printing (Inkjet & Xerography), Gravure, Screen Printing.
3D printing which is also referred as additive printing technology that enables manufacturers to develop objects using a digital file and variety of printing materials. Global market for 3D printing material includes polymers, metals and ceramics. In addition, 3D printing offers a wide array of applications in various industries, namely consumer products, industrial products, defense & aerospace, automotive, healthcare, education & research and others.
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https://goo.gl/07Bdmz
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Contact us
Niir Project Consultancy Services
106-E, Kamla Nagar, Opp. Spark Mall,
New Delhi-110007, India.
Email: npcs.ei@gmail.com , info@entrepreneurindia.co
Tel: +91-11-23843955, 23845654, 23845886, 8800733955
Mobile: +91-9811043595
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Take a look at NIIR PROJECT CONSULTANCY SERVICES on #StreetView
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How to Start printing Industry in India, Offset Printing Industry in India, Most Profitable Printing Business Ideas, Flexography printing Profitable Project, 3D Printing Project, Small Scale Printing Projects, Starting a 3-D Printing Business, How to Start Gravure Printing Business, Digital printing Based Small Scale Industries Projects, New small scale ideas in Offset Printing industry, NPCS, Niir, Process technology books, Business consultancy, Business consultant, Project identification and selection, Preparation of Project Profiles, Start up, Business guidance, Business guidance to clients, Start-up Project for 3-D Printing industry, Start-up Project, Start-up ideas, Project for start-ups, Start-up project plan, Business start-up, Business Plan for a Start-up Business, Great Opportunity for Start-up, Small Start-up Business Project, Start-up Business Plan for 3D Printing industry, Start Up India, Stand Up India, Digital Printing, Small scale Offset Printing machine, 3D Printing machine, Modern small and cottage scale industries, Profitable small and cottage scale industries, Setting up and opening your printing Business, How to Start printing press?,
3D printing involves using computer-controlled layering to create 3D objects from digital files. The most common technologies are Fused Deposition Modeling (FDM), Stereolithography (SLA), and Selective Laser Sintering (SLS). To get started with 3D printing, you need a 3D printer, filament or resin, a CAD program, 3D model files, and a slicer program to prepare files for printing. Popular desktop 3D printers start around $183, or you can access printers through services like 3D Hubs. Common materials include PLA, ABS, and resins for SLA printers.
El documento describe los diferentes métodos de calcografía, el arte de hacer grabados en metal. Explica que existen métodos directos que usan herramientas cortantes para incidir la plancha y métodos indirectos que usan ácidos. Describe técnicas como el buril, la punta seca, la mezzotinta, el aguafuerte y la aguatinta.
In this presentation i have described about nanotechnology in present and future automobiles.And i also gave applications regarding nanotechnology in automobiles.
This document discusses various 3D printing technologies including fused deposition modeling (FDM), stereolithography (SLA), photopolymer phase change inkjets, selective laser sintering (SLS), and plaster-based 3D printing. It describes the basic processes and materials used for each technology. For FDM, it explains how a filament is extruded through a heated nozzle to fuse layers together and discusses common thermoplastic materials like PLA and ABS. For SLA, it describes how a laser cures liquid resin in layers. For SLS/DMLS, it explains how a high-power laser sinters or fuses powdered materials in layers.
Selective Laser Sintering is one of the most used processes of Rapid Prototyping. It is a powder based process where powder of different metals/materials get sintered by LASER.
This is the seminar report of my presentation
Link for the pressentaion file is
http://www.slideshare.net/arjunrtvm/3d-printing-additive-manufacturing-with-awesome-animations-and-special-effects
1. The document discusses various types of printing and finishing machinery used in the textile industry, including block printing machines, roller printing machines, stencil printing machines, and digital printing machines.
2. It describes specific printing processes like hand block printing and roller printing in detail. Finishing machinery discussed include mercerizing machines and softening machines.
3. Printing and finishing machinery play a crucial role in the textile industry by allowing for design, improving fabric quality, and making textiles suitable for various end uses.
Nanomaterials are materials that have at least one dimension sized between 1 to 100 nanometers. They exhibit unique optical, electrical, and magnetic properties compared to bulk materials due to their small size and large surface area. This document discusses several methods for synthesizing nanomaterials, including mechanical grinding, sol-gel processing, and wet chemical synthesis. Mechanical grinding uses ball milling to break down bulk materials into nanoparticles. Sol-gel processing involves hydrolysis and condensation reactions of metal alkoxides to form colloidal solutions and gels that can be dried and sintered into nanomaterials. Wet chemical synthesis includes both top-down methods like electrochemical etching and bottom-up approaches like precipitation from solution.
This document provides an overview of rapid prototyping (RP). It defines RP as a family of fabrication methods to quickly make engineering prototypes based on CAD models with minimum lead times. The document discusses the evolution of prototyping, the need for RP, different RP categories including material removal and addition processes, the steps to prepare RP control instructions from a CAD model, common RP technologies like stereolithography and fused deposition modeling, applications of RP in design, engineering analysis and tooling, and challenges with part accuracy and limited materials.
This document discusses various etching techniques used in microfabrication processes. It describes isotropic and anisotropic etching, and how etch rate and profile depend on the orientation of the crystalline planes. Wet etching involves immersing wafers in chemical solutions and proceeds equally in all directions, limiting it to features larger than 3um. Dry etching uses gases or plasma and can achieve better anisotropy. The document outlines properties of etch processes like rate, uniformity, profile and selectivity. It provides examples of wet etch chemistries and discusses advantages and disadvantages of wet versus dry etching.
This document discusses profilometers, which are devices used to measure surface roughness. It describes the two main types - contact and non-contact profilometers. Non-contact profilometers use optical techniques like interferometry to measure surfaces without touching them, while contact profilometers use a physical stylus. The document outlines various measurement techniques, performance parameters, surface topography concepts, and examples of profilometers available at IISc. It provides an overview of profilometry for measuring and analyzing surface roughness.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Theoretical work submitted to the Journal should be original in its motivation or modeling structure. Empirical analysis should be based on a theoretical framework and should be capable of replication. It is expected that all materials required for replication (including computer programs and data sets) should be available upon request to the authors.
The International Journal of Engineering & Science would take much care in making your article published without much delay with your kind cooperation
Trent Smith completed a mechanical engineering internship at Hewlett-Packard where he worked on several projects to improve product quality and prevent failures. His major projects included designing experiments to characterize the impact of material and process variations on laser weld strength, quantitatively analyzing residual mold stress in transparent parts using a polarimeter, and supporting a prototype manufacturing line. Through hands-on learning experiences with plastics, manufacturing, and statistical analysis, Trent gained valuable skills and knowledge that will benefit his career. His work directly helped HP optimize processes, reduce costs, and avoid delays.
SLS is a rapid prototyping process that uses a laser to fuse powdered material like plastic, metal, or ceramic into a solid 3D object. A laser selectively fuses powdered material layer by layer based on a CAD model. The unfused powder acts as a support material and is removed after the build. SLS can produce parts with complex geometries from a variety of materials without the need for additional support structures.
The document discusses calendering of paper and board. It provides details on:
1) The calendering process which involves pressing paper between rolls to smooth and gloss the surface. Key variables include nip impulse, web temperature and moisture.
2) Conventional calendering methods including machine, brush, soft and multi-nip calendering. Multi-nip calendering is needed for certain grades to achieve the desired smoothness and gloss.
3) New calendering methods like metal belt calendering which extends the dwell time under heat for better smoothness, coating layer and printability.
Optical Lithography, Key Enabling Technology for our Modern WorldReinhard Voelkel
In 1959, Richard P. Feynman initiated the Nano-age in his lecture “There’s plenty of room at the bottom”. Feynman also had a clear vision about computers and asked: ”Why can’t we make them very small, make them of little wires, little elements - and by little, I mean little. For instance, the wires should be 10 or 100 atoms in diameter, and the circuits should be a few thousand angstroms across.”
At the same time, Jean Hoerni from Fairchild Semiconductors tried to get his “planar process” to production. Hoerni’s planar process using silicon substrates, so-called “wafers”, revolutionized semiconductor manufacturing and was widely adapted by the industry. The great success of the planar wafer process is also much related with tremendous improvements in optical lithography over all the years. From the early age dominated by mask aligners to highly sophisticated steppers and scanners, lithography was the key enabling technology, allowing now – 50 years after Feynman’s vision – nanostructuring down to the atomic scale on 300mm planar wafers. The evolutionary development of optical lithography is reviewed along with a brief discussion of options for the future.
This document provides an overview of selective laser sintering (SLS), a 3D printing technique that uses a laser to fuse powdered material together layer by layer. It defines SLS, describes the basic multi-step process, and lists common input parameters and materials used. The document outlines key advantages like lack of support structures and fast printing, as well as limitations such as prints being brittle and prone to warping. A variety of applications are mentioned, including aerospace, medical, electronics, and automotive uses.
The document discusses ion beam etching, which is a physical dry etching process. Ion beam etching works by ionizing an inert gas like argon to create a plasma of positive ions and electrons. The ions are accelerated towards the target material, physically removing atoms from the surface through sputtering. Ion beam etching is highly directional and provides precise etching with minimal damage to the substrate. It can etch all materials and is used for applications requiring long lifetimes and precise specifications, like microelectronics and sensors.
This document provides an overview of metal drawing operations. It discusses the introduction to drawing, general operations like conditioning materials, process descriptions for shapes like rods/wires and tubes. It covers process requirements including tools, equipment, dies and load calculations. The key points are that metal drawing is a process that uses tensile forces to reduce cross-sectional area and elongate metal by pulling it through a die, important factors include the amount of reduction, speed, material properties and temperature. It can produce various shapes like rods, wires and tubes for different applications.
Printing Technology (Offset, Flexo, Gravure, Screen, Digital, 3D Printing) (Noncontact Printing ,Commercial Printing, Gravure Printing, Letterpress Printing, Offset Printing, Screen Printing, Offset Lithography, Lanography ,Flexography, Rotogravure, Digital Printing,3D Printing, 3D Printing Machinery, Blanket Cylinder, Plate Cylinder, Impression Cylinder, Web Offset Machines, printing press)
Printing is a process of producing copies of text and pictures. Modern technology is radically changing the way publications are printed, inventoried and distributed. There are a wide variety of technologies that are used to print stuff. The main industrial printing processes are: Offset Lithography, Flexography, Digital Printing (Inkjet & Xerography), Gravure, Screen Printing.
3D printing which is also referred as additive printing technology that enables manufacturers to develop objects using a digital file and variety of printing materials. Global market for 3D printing material includes polymers, metals and ceramics. In addition, 3D printing offers a wide array of applications in various industries, namely consumer products, industrial products, defense & aerospace, automotive, healthcare, education & research and others.
See more
https://goo.gl/07Bdmz
https://goo.gl/jKfCWf
https://goo.gl/EJ7x26
Contact us
Niir Project Consultancy Services
106-E, Kamla Nagar, Opp. Spark Mall,
New Delhi-110007, India.
Email: npcs.ei@gmail.com , info@entrepreneurindia.co
Tel: +91-11-23843955, 23845654, 23845886, 8800733955
Mobile: +91-9811043595
Website : www.entrepreneurindia.co , www.niir.org
Take a look at NIIR PROJECT CONSULTANCY SERVICES on #StreetView
https://goo.gl/VstWkd
Tags
How to Start printing Industry in India, Offset Printing Industry in India, Most Profitable Printing Business Ideas, Flexography printing Profitable Project, 3D Printing Project, Small Scale Printing Projects, Starting a 3-D Printing Business, How to Start Gravure Printing Business, Digital printing Based Small Scale Industries Projects, New small scale ideas in Offset Printing industry, NPCS, Niir, Process technology books, Business consultancy, Business consultant, Project identification and selection, Preparation of Project Profiles, Start up, Business guidance, Business guidance to clients, Start-up Project for 3-D Printing industry, Start-up Project, Start-up ideas, Project for start-ups, Start-up project plan, Business start-up, Business Plan for a Start-up Business, Great Opportunity for Start-up, Small Start-up Business Project, Start-up Business Plan for 3D Printing industry, Start Up India, Stand Up India, Digital Printing, Small scale Offset Printing machine, 3D Printing machine, Modern small and cottage scale industries, Profitable small and cottage scale industries, Setting up and opening your printing Business, How to Start printing press?,
3D printing involves using computer-controlled layering to create 3D objects from digital files. The most common technologies are Fused Deposition Modeling (FDM), Stereolithography (SLA), and Selective Laser Sintering (SLS). To get started with 3D printing, you need a 3D printer, filament or resin, a CAD program, 3D model files, and a slicer program to prepare files for printing. Popular desktop 3D printers start around $183, or you can access printers through services like 3D Hubs. Common materials include PLA, ABS, and resins for SLA printers.
El documento describe los diferentes métodos de calcografía, el arte de hacer grabados en metal. Explica que existen métodos directos que usan herramientas cortantes para incidir la plancha y métodos indirectos que usan ácidos. Describe técnicas como el buril, la punta seca, la mezzotinta, el aguafuerte y la aguatinta.
In this presentation i have described about nanotechnology in present and future automobiles.And i also gave applications regarding nanotechnology in automobiles.
This document discusses various 3D printing technologies including fused deposition modeling (FDM), stereolithography (SLA), photopolymer phase change inkjets, selective laser sintering (SLS), and plaster-based 3D printing. It describes the basic processes and materials used for each technology. For FDM, it explains how a filament is extruded through a heated nozzle to fuse layers together and discusses common thermoplastic materials like PLA and ABS. For SLA, it describes how a laser cures liquid resin in layers. For SLS/DMLS, it explains how a high-power laser sinters or fuses powdered materials in layers.
Selective Laser Sintering is one of the most used processes of Rapid Prototyping. It is a powder based process where powder of different metals/materials get sintered by LASER.
This is the seminar report of my presentation
Link for the pressentaion file is
http://www.slideshare.net/arjunrtvm/3d-printing-additive-manufacturing-with-awesome-animations-and-special-effects
1. The document discusses various types of printing and finishing machinery used in the textile industry, including block printing machines, roller printing machines, stencil printing machines, and digital printing machines.
2. It describes specific printing processes like hand block printing and roller printing in detail. Finishing machinery discussed include mercerizing machines and softening machines.
3. Printing and finishing machinery play a crucial role in the textile industry by allowing for design, improving fabric quality, and making textiles suitable for various end uses.
Nanomaterials are materials that have at least one dimension sized between 1 to 100 nanometers. They exhibit unique optical, electrical, and magnetic properties compared to bulk materials due to their small size and large surface area. This document discusses several methods for synthesizing nanomaterials, including mechanical grinding, sol-gel processing, and wet chemical synthesis. Mechanical grinding uses ball milling to break down bulk materials into nanoparticles. Sol-gel processing involves hydrolysis and condensation reactions of metal alkoxides to form colloidal solutions and gels that can be dried and sintered into nanomaterials. Wet chemical synthesis includes both top-down methods like electrochemical etching and bottom-up approaches like precipitation from solution.
This document provides an overview of rapid prototyping (RP). It defines RP as a family of fabrication methods to quickly make engineering prototypes based on CAD models with minimum lead times. The document discusses the evolution of prototyping, the need for RP, different RP categories including material removal and addition processes, the steps to prepare RP control instructions from a CAD model, common RP technologies like stereolithography and fused deposition modeling, applications of RP in design, engineering analysis and tooling, and challenges with part accuracy and limited materials.
This document discusses various etching techniques used in microfabrication processes. It describes isotropic and anisotropic etching, and how etch rate and profile depend on the orientation of the crystalline planes. Wet etching involves immersing wafers in chemical solutions and proceeds equally in all directions, limiting it to features larger than 3um. Dry etching uses gases or plasma and can achieve better anisotropy. The document outlines properties of etch processes like rate, uniformity, profile and selectivity. It provides examples of wet etch chemistries and discusses advantages and disadvantages of wet versus dry etching.
This document discusses profilometers, which are devices used to measure surface roughness. It describes the two main types - contact and non-contact profilometers. Non-contact profilometers use optical techniques like interferometry to measure surfaces without touching them, while contact profilometers use a physical stylus. The document outlines various measurement techniques, performance parameters, surface topography concepts, and examples of profilometers available at IISc. It provides an overview of profilometry for measuring and analyzing surface roughness.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Theoretical work submitted to the Journal should be original in its motivation or modeling structure. Empirical analysis should be based on a theoretical framework and should be capable of replication. It is expected that all materials required for replication (including computer programs and data sets) should be available upon request to the authors.
The International Journal of Engineering & Science would take much care in making your article published without much delay with your kind cooperation
Trent Smith completed a mechanical engineering internship at Hewlett-Packard where he worked on several projects to improve product quality and prevent failures. His major projects included designing experiments to characterize the impact of material and process variations on laser weld strength, quantitatively analyzing residual mold stress in transparent parts using a polarimeter, and supporting a prototype manufacturing line. Through hands-on learning experiences with plastics, manufacturing, and statistical analysis, Trent gained valuable skills and knowledge that will benefit his career. His work directly helped HP optimize processes, reduce costs, and avoid delays.
SLS is a rapid prototyping process that uses a laser to fuse powdered material like plastic, metal, or ceramic into a solid 3D object. A laser selectively fuses powdered material layer by layer based on a CAD model. The unfused powder acts as a support material and is removed after the build. SLS can produce parts with complex geometries from a variety of materials without the need for additional support structures.
erimental Investigation of Process Parameter on Tensile Strength of Selective...ijsrd.com
Selective Laser Melting (SLM) is an emerging, fast growing rapid prototyping (RP) technology due to its ability to build functional parts having complex geometrical shape in reasonable time period. The quality of built parts highly depends on many process variables in selective laser melting. In this study, three important SLM process parameters such as layer thickness, orientation angle and scan speed are considered. Their influence on tensile strength of test specimen is studied. Margining Steel having grade 1.2709 was the material, commercially named CL50WS, which is used for fabricate Tensile Specimen in SLM. The experiments are conducted based on Taguchi's L8 orthogonal array. The validity of process parameter and response is tested by using analysis of variance (ANOVA). The multi linear regression model is developed in order to predict Tensile strength of test specimen. The experimental data and data obtained by regression equation is closely correlated which validated the models. The layer thickness and scan speed is highly affect the quality of SLM fabricated parts whereas orientation angle have little important.
This document is a project report on simulating graphene-based transistors for digital and analog applications. It was completed by three students at the National Institute of Technology in Patna, India under the guidance of Dr. M.W. Akram. The report describes using the NanoTCAD ViDES simulation software to model graphene nanoribbon field-effect transistors and analyze their performance. It discusses the motivation to study new channel materials like graphene due to the limitations of Moore's law. The properties of graphene and graphene nanoribbons are also summarized.
My dissertation on electrospray ionisation process. What is the effect of temperature, salt concentration (tension), charge and electric field on the process. Which model is dominant: CRM or IEM?
This document provides an overview of selective laser sintering (SLS) technology. It discusses the history and development of SLS, the SLS process, materials that can be used, applications, advantages and limitations. Recent developments discussed include using SLS to create electrical devices, 3D print in color, and develop drug delivery devices. Potential future applications highlighted are in the medical, aerospace, automotive and manufacturing industries, with a focus on increased speed, accuracy, size capacity and new materials like metals.
Role of Simulation in Deep Drawn Cylindrical PartIJSRD
Simulation is widely used in forming industry due to its speed and lower cost and it has been proven to be effective in prediction of formability and spring back behavior. The purpose of finite element simulation in the sheet metal forming process is to minimize the time and cost in the design phase by predicting key outcomes such as the final shape of the part, the possibility of various defects and the flow of material. Such simulation is most useful and efficient when it is performed in the early stage of design by designers, rather than by analysis specialists after the detailed design is complete. The accuracy of such simulation depends on knowledge of material properties, boundary conditions and processing parameters. In the industry today, numerical sheet metal forming simulation is very important tool for reducing load time and improving part quality. In this paper finite element model for the deep-drawing of cylindrical cups is constructed and the simulation results are obtained by using different simulation parameters, i.e. punch velocity, coefficient of friction and blank holder force of the FE mesh-elements and these results are compared with experimental work.
IEEE Student Branch Chittagong University arranged a webinar titled "From APECE to ASML A Semiconductor Journey". Shawn Millat shared his working experience in Semiconductor industry and also shared tips about studying in Germany.
Rapid prototyping (RP) has emerged as a key enabling technology that can shorten product design and development time. This article discusses the role of RP in 'time compression' engineering and provides a brief description of three RP processes: stereolithography, selective laser sintering, and fused deposition modelling. The article also outlines different applications of RP technology in areas like functional models, patterns for investment casting, and medical/surgical models. Finally, it discusses future developments needed to further advance this field.
This document presents a finite element analysis of a stepped bar subjected to axial loading using MATLAB and ANSYS. It begins with an introduction to finite element analysis and describes how MATLAB and ANSYS can be used to model and analyze engineering problems. The document then outlines the specific procedure used to analyze a stepped bar, including defining the problem, developing the analytical solution, and determining displacements and stresses at nodes. The results obtained from MATLAB and finite element analysis are shown to be similar, while ANSYS results are also close. The document concludes the analysis methods allow solving problems efficiently and with less error compared to manual calculations.
Improvement of Surface Roughness of Nickel Alloy Specimen by Removing Recast ...IJMER
Abstract: In this investigation, experimental work and computational work are combined to obtain improvement in the surface roughness of nickel alloy specimen, the machining is carried out by means of CNC wire electric discharge machining (WEDM). Brass wire is used as the tool electrode and nickel alloy (Inconel600) is used as the work piece material. The machining parameters such as Pulse-On time (Ton), Pulse-Off time (Toff), Peak Current (Ip), and Bed speed are considered as input parameters for this project. Surface roughness and Recast layer are considered the output parameters. The experiments
with the pre-planned set of input parameters are designed based on Taguchi’s orthogonal array. The surface roughness is measured using stylus type roughness tester and the thickness of the Recast layer is measured using Scanning Electron Microscope (SEM). The results obtained from the experiments are fed to the Minitab software and optimum input parameters for the desired output parameters are identified. The software uses the concept of analysis of variance (ANOVA) and indicates the nature of effect of input parameters on the output parameters and confirmation is done by validation
experiments. Once the recast layer thickness is obtained Chemical Etching and abrasive blasting is performed in order to remove the recast layer and again the surface roughness is measured by using stylus type roughness tester. Finally from the obtained results it was found that there was significant improvement in the Surface roughness of the nickel alloy material. In addition using regression analysis this work is stimulated by computational method and the results are obtained
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This thesis extends the electromagnetic field calculation capabilities of the open-source CFD software OpenFOAM. It develops new solvers within OpenFOAM to solve magnetostatic problems for materials like copper, steel, and permanent magnets. Two formulations (A-V and A-J) are derived from Maxwell's equations and implemented as OpenFOAM solvers through custom C++ code. Force calculation methods are also implemented to calculate Lorenz force and Maxwell stress. Simple test cases are modeled and solved to validate the new solvers. Results are compared to COMSOL Multiphysics and good agreement is found. The developed solvers could be applied to the design of electromagnetic devices like electric machines.
This document provides an introduction to engineering design. It discusses how design involves both analysis and synthesis skills. Design can be viewed as an optimization process, but is complicated by factors like conflicting objectives, nonlinear relationships, and component variations. Requirements are important to guide design, but not all requirements are equal constraints - some may be softened based on feasibility. Specifications provide measurable definitions to test if a design meets requirements. The document aims to expand the reader's view of all that is involved in engineering design.
Computational Intelligence Approach for Predicting the Hardness Performances ...Waqas Tariq
This paper presents a computational approach on predicting of hardness performances for Titanium Aluminium Nitride (TiA1N) coating process. A new application in predicting the hardness performances of TiA1N coatings using a method called Support Vector Machine (SVM) and Artificial Neural Network (ANN) is implemented. TiAlN coatings are usually used in high-speed machining due to its excellent properties in surface hardness and wear resistance. Physical Vapor Deposition (PVD) magnetron sputtering process has been used to produce the TiA1N coatings. Based on the experimental dataset of previous work, the SVM and ANN model is used in predicting the hardness of TiA1N coatings. The influential factors of three coating process parameter namely substrate sputtering power, substrate bias voltage and substrate temperature were selected as input while the output parameter is the hardness. The results of proposed SVM and ANN models are compared to the experimental result and the hybrid RSM-Fuzzy model from previous work. The comparisons of SVM and ANN models against hybrid RSM-Fuzzy were based on predictive performances in order to obtain the most accurate model for prediction of hardness in TiA1N coating. In terms of predictive performance evaluation, four performances matrix were applied that are percentage error, mean square error (MSE), co-efficient determination (R 2) and model accuracy. The result has proved that the proposed SVM model shows the better result compared to the ANN and hybrid RSM-fuzzy model. The good performances of the results obtained by the SVM method shows that this method can be applied for prediction of hardness performances in TiA1N coating process with better predictive performances compared to ANN and hybrid RSM-Fuzzy.
This document contains information about a laboratory manual for a Digital Image Processing course. It includes the vision, mission, and objectives of the Electronics and Telecommunication department. It describes the contents of the laboratory manual, which contains practical lab sessions to enhance understanding of various aspects related to digital image processing. The document recommends that students thoroughly review the manual to better understand theoretical concepts in books through practical aspects.
Coherent, Whitepaper: LAM - Laser Additive Manufacturing with new laser power...Dirk Grebert
Novel Beam Diagnostics Improve Laser Additive Manufacturing.
Laser additive manufacturing (LAM) is rapidly becoming an important method for the fabrication
of both prototype and production metal parts.
Now, a novel system from Haas Laser Technologies addresses both these issues. It can deliver
very rapid measurements of beam mode, and nearly instantaneous power for both CW and
pulsed, high power lasers using PowerMax™-Pro sensing technology from Coherent.
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In order to directly measure beam power, which is critical for the system to accurately calculate
laser power density at the precise location the powder layer is being processed, the system
incorporates a Coherent PowerMax-Pro detector. This utilizes a relatively new type of detector
technology called a transverse thermoelectric (Patent #9,059,346), first introduced to the market
in 2014, which combines the broad wavelength sensitivity, dynamic range and laser damage
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Effects of Various Material Infiltrants in Sls Processtheijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Theoretical work submitted to the Journal should be original in its motivation or modeling structure. Empirical analysis should be based on a theoretical framework and should be capable of replication. It is expected that all materials required for replication (including computer programs and data sets) should be available upon request to the authors.
The International Journal of Engineering & Science would take much care in making your article published without much delay with your kind cooperation
1. The document summarizes a study on the effects of infiltrating stainless steel parts produced by selective laser sintering (SLS) with different materials, including bronze, brass, and bell metal.
2. Hardness, dimensional accuracy, bending strength, and surface roughness of the infiltrated stainless steel parts were evaluated. Bronze infiltration produced parts with the highest hardness while brass infiltration led to the best dimensional stability.
3. The study aims to determine the optimal infiltrant material for SLS stainless steel parts to improve mechanical properties and quality of final products.
Abstract— This paper demonstrates overcoming of the Abbe diffraction limit (ADL) on image resolution. Here, terahertz multispectral reconstructive imaging has been described and used for analyzing nanometer size metal lines fabricated on a silicon wafer. It has also been demonstrated that while overcoming the ADL is a required condition, it is not sufficient to achieve sub-nanometer image resolution with longer wavelengths. A nanoscanning technology has been developed that exploits the modified Beer-Lambert’s law for creating a measured reflectance data matrix and utilizes the ‘inverse distance to power equation’ algorithm for achieving 3D, sub-nanometer image resolution. The nano-lines images reported herein, were compared to SEM images. The terahertz images of 70 nm lines agreed well with the TEM images. The 14 nm lines by SEM were determined to be ~15 nm. Thus, the wavelength dependent Abbe diffraction limit on image resolution has been overcome. Layer-by-layer analysis has been demonstrated where 3D images are analyzed on any of the three orthogonal planes. Images of grains on the metal lines have also been analyzed. Unlike electron microscopes, where the samples must be in the vacuum chamber and must be thin enough for electron beam transparency, terahertz imaging is non-destructive, non-contact technique without laborious sample preparation.
Similar to USE THE LASER ENGRAVING MACHINES TO ACHIEVE LASER CLEANING, LASER POST-MELTING AND ROUGHNESS CONTROL OF THE ANILOX ROLLS (20)
The Free Energy Secrets of Cold ElectricityNOMADPOWER
The phenomenon of consumer devices becoming cold as they consume power is a sign that "Cold Electricity" is powering a consuming device. In terms of its form, "Cold Electricity" also has a voltage supply that produces the same current as a conventional power source. Conventional power from the grid generates work on consuming devices and at the same time gives off heat. But with a Cold Electricity supply, the power-consuming loads tend to absorb the temperature in the environment, meaning they do not emit heat but, on the contrary, collect heat, i.e., get cold during operation.
An Experimental Study on the Migration of Pb in the Groundwater Table Fluctua...NOMADPOWER
As a result of fluctuations in the shallow groundwater table, hydrodynamic conditions change alongside environmental conditions and hydrogeochemical processes to affect pollutant migration. The study aimed to investigate the migration, adsorption, and desorption characteristics of Pb on fine, medium, and coarse sand in the water table fluctuation zone by using several laboratory methods, including the kinetic aspects of Pb2+ adsorption/desorption and water table fluctuation experiments.
An optimized snowmelt lysimeter system for monitoring melt rates and collecti...NOMADPOWER
The contribution of snow meltwater to catchment streamflow can be quantified through hydrograph separation analyses for which stable water isotopes (18 O, 2 H) are used as environmental tracers. For this, the spatial and temporal variability of the isotopic composition of meltwater needs to be captured by the sampling method. This study compares an optimized snowmelt lysimeter system and an unheated precipitation collector with focus on their ability to capture snowmelt rates and the isotopic composition of snowmelt.
Adsorptive/photo-catalytic process for naphthalene removal from aqueous media...NOMADPOWER
The problem being addressed in this study is the removal of naphthalene from aqueous media using an adsorptive/photo-catalytic process. The proposed solution involves the use of an in-situ nickel doped titanium nanocomposite as a catalyst to degrade the naphthalene molecules. The effectiveness of this process is being tested in order to provide a potential solution for the removal of naphthalene from industrial wastewater and other contaminated water sources.
This document summarizes an experimental study of earth batteries as an alternative energy source. Various metal combinations were tested as electrodes, with zinc-copper cells providing around 0.9 volts. Small electronic devices were successfully powered by individual cells. Increasing the number of cells in series increased the voltage output linearly, while connecting cells in parallel increased the current output. Further testing aimed to optimize electrode materials and configurations to increase power levels for potential applications in remote areas lacking electricity access.
FIRST AID FOR SOLDIERS FM 21-11, Special Operations Forces Medical HandbookNOMADPOWER
These manuals meets the first aid training needs of individual service
members. Because medical personnel will not always be readily available,
the nonmedical service members must rely heavily on their own skills and
knowledge of life-sustaining methods to survive on the integrated battlefield.
This publication outlines both self-aid and aid to other service members
(buddy aid). More importantly, it emphasizes prompt and effective action in
sustaining life and preventing or minimizing further suffering and disability.
First aid is the emergency care given to the sick, injured, or wounded before
being treated by medical personnel. The term first aid can be defined as
“urgent and immediate lifesaving and other measures, which can be
performed for casualties by nonmedical personnel when medical personnel
are not immediately available.” Nonmedical service members have received
basic first aid training and should remain skilled in the correct procedures for
giving first aid. This manual is directed to all service members. The
procedures discussed apply to all types of casualties and the measures
described are for use by both male and female service members.
I should only close epidermal wounds, and then only if I must because I cannot get proper medical help to do it for me. (I know I will be soundly criticized for that comment, but I am entitled to my opinion, even if you disagree with it.)
Suturing should be low on my list of options for closing a wound. I should keep the book available as a reference for a trained medical professional. Deep wounds require special care, which means expertise beyond the training most of us non- professionals can acquire and maintain.
If I absolutely must close a wound that really needs a doctor to do it, I need this book to have a chance of doing a decent job of it.
Survival Personal Wilderness Medical KitNOMADPOWER
Most of us would agree that at any moment we could find ourselves in a disaster or other emergency situation. Even if this fact is only lurking in the back of the mind just below consciousness, the statement is no less true. Anyone can suddenly be thrust into an emergency situation or have a disaster land squarely upon them quite unexpectedly. How well one survives or IF one survives may be a matter of luck. Far better to invest some time and effort in survival preparedness.
Most will not met the harsh invironment that is talked about in thhe book. Most will never find themselves in need of knowing half of what is in the book. But everyone should have the book close at hand. With the rise of crime and terrorisem there are many good point that one can learn from not only this manual, but the others tha come with it. One could say we are in our time at the same point that Rome was just before its fall. Does that help you understand why you should get this "Handbook"? I would have given it a higher rating but we are talking about a military manual, not writen for bedtime reading.
Sustainable Strategies for the Exploitation of End-of-Life Permanent MagnetsNOMADPOWER
Rare Earth Magnets (REM), especially the NdFeB type, are essential components in high-performance electric motors and wind turbines, playing an important role in the shift towards a low-carbon energy matrix. However, little work has been done to understand how the production of REM can be in line with the global sustainable transition. To overcome this lack and help with future research, as well as decision-making, this paper provides a literature overview of which aspects of sustainability are being investigated in the REM supply chain, and how each of them contributes to achieving Sustainable Development Goals (SDG). This research is developed through a consistent analysis of 44 peer-reviewed publications, followed by an analysis of strengths, weaknesses, opportunities, and threats. Four main subjects of studies were identified: environmental impact; social impact; economic aspects and circular economy. Most of the studies focus on computing the environmental impact through life cycle assessment and discussing techniques towards exploring the circular economy concept. In addition to contributing to a greener economy, the majors identified strengths of REM are the great potential of its supply chain in reducing primary resource extraction, since REM recovery and recycling seem to be viable, and the promising techniques to minimize environmental impacts along the rare earth elements production chain.
In the focus of attention at the present time are the new rare earth‐cobalt‐based magnet alloys. This paper is primarily a qualitative review of the physical phenomena controlling their behavior and of the materials problems these magnets have posed. It also provides an outlook at possibilities for the development of still better or cheaper permanent magnets which current research on rare earth‐ transition metal alloys appears to provide. The origins of the magnetic moments and the crystal anisotropy of rare earth‐transition metal phases are discussed. Alternative concepts of the causes of coercivity in powders and sintered bodies are analyzed. Some basic aspects of the sintering of R‐Co compacts and the magnetic hardening of R–Co–Cu alloys in the massive state are reviewed. Specific problems related to particular alloys and applications of the magnets are pointed out. The conclusion is drawn that the new family of permanent magnets now emerging rivals in complexity both the Alnicos and the ferrites together. There are many development opportunities for the future, and we can expect that, eventually, magnets based on high‐anisotropy alloys containing rare earths will be offered in a variety of grades, covering a wide range of properties and prices, and that they will be produced by several drastically different methods.
Characteristics of Nd-Fe-B Permanent Magnets Present in Electronic ComponentsNOMADPOWER
In the present study the amount of permanent magnets (PM) present in waste of electrical and electronic equipment (WEEE) has been quantified. The PM was subsequently characterised by – among other techniques – scanning electron microscopy (SEM) using the TESCAN FEG-SEM MIRA3. The SEM results show that the magnets containing rare earth elements (REE) present in WEEE consist of Nd- Fe-B alloy in a tetrahedral form with an inter-granular space rich in REEs (Nd, Dy and Pr). About 20 μm thick coating layer consisting of Ni, Zn or an alloy of Cu/Ni is detected at the surface of the magnets. Properties of the PM at high temperatures are further investigated.
GraphSummit Singapore | The Art of the Possible with Graph - Q2 2024Neo4j
Neha Bajwa, Vice President of Product Marketing, Neo4j
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Cosa hanno in comune un mattoncino Lego e la backdoor XZ?Speck&Tech
ABSTRACT: A prima vista, un mattoncino Lego e la backdoor XZ potrebbero avere in comune il fatto di essere entrambi blocchi di costruzione, o dipendenze di progetti creativi e software. La realtà è che un mattoncino Lego e il caso della backdoor XZ hanno molto di più di tutto ciò in comune.
Partecipate alla presentazione per immergervi in una storia di interoperabilità, standard e formati aperti, per poi discutere del ruolo importante che i contributori hanno in una comunità open source sostenibile.
BIO: Sostenitrice del software libero e dei formati standard e aperti. È stata un membro attivo dei progetti Fedora e openSUSE e ha co-fondato l'Associazione LibreItalia dove è stata coinvolta in diversi eventi, migrazioni e formazione relativi a LibreOffice. In precedenza ha lavorato a migrazioni e corsi di formazione su LibreOffice per diverse amministrazioni pubbliche e privati. Da gennaio 2020 lavora in SUSE come Software Release Engineer per Uyuni e SUSE Manager e quando non segue la sua passione per i computer e per Geeko coltiva la sua curiosità per l'astronomia (da cui deriva il suo nickname deneb_alpha).
Communications Mining Series - Zero to Hero - Session 1DianaGray10
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• Why is it important?
• How can it help today’s business and the benefits
• Phases in Communication Mining
• Demo on Platform overview
• Q/A
Infrastructure Challenges in Scaling RAG with Custom AI modelsZilliz
Building Retrieval-Augmented Generation (RAG) systems with open-source and custom AI models is a complex task. This talk explores the challenges in productionizing RAG systems, including retrieval performance, response synthesis, and evaluation. We’ll discuss how to leverage open-source models like text embeddings, language models, and custom fine-tuned models to enhance RAG performance. Additionally, we’ll cover how BentoML can help orchestrate and scale these AI components efficiently, ensuring seamless deployment and management of RAG systems in the cloud.
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...Neo4j
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Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
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Removing Uninteresting Bytes in Software FuzzingAftab Hussain
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USE THE LASER ENGRAVING MACHINES TO ACHIEVE LASER CLEANING, LASER POST-MELTING AND ROUGHNESS CONTROL OF THE ANILOX ROLLS
1. Internship report in Apex – Han Jin
0
INTERNSHIP REPORT
Use the laser engraving machines to achieve
laser cleaning, laser post-melting and
roughness control of the anilox rolls.
Report of a three month internship
at Apex Europe B.V. in Hapert, the
Netherlands (20 EC).
Time duration:
01/09/2015 to
30/11/2015
Han Jin s1530208
SET, CTW
Best Survival Programs Laser Engraving Machine Home woodworking plans
2. Internship report in Apex – Han Jin
1
Title: Internship report
Subtitle: Use the laser engraving machines to achieve laser cleaning, laser post-melting and
roughness control of the anilox rolls. Report of a three month internship at Apex Europe B.V.
in Hapert, the Netherlands, as part of the master program Sustainable Energy Technology
(20 EC).
Name: Han Jin
Student number: s1530208
Period: 01/09/2015 - 01/12/2015
Supervisor APEX: Toon van Steensel
Supervisor University of Twente: Gert-Willem Römer
Host Institution:
Apex Europe B.V.
Metaalweg 8
5527 AK Hapert
The Netherlands
Tel. + 31 (0) 497 36 11 11
Fax. + 31 (0) 497 36 11 22
E-mail: info@apex-europe.com
Home institution:
University of Twente
Faculty of Engineering Technology
Chair of Applied Laser Technology
PO Box 217
7500 AE Enschede, the Netherlands
Best Survival Programs Laser Engraving Machine Home woodworking plans
3. Internship report in Apex – Han Jin
2
Preface
I was very lucky to have this internship chance in Apex. First of all, all the colleagues,
especially Toon and the laser room group companions, they were all very kind to me and
gave me a lot of help during the whole three months. The company is very generous, making
me comfortable both in the working and also living circumstances.
These three months gave me the precious experience of working in a dutch company.
And in the meantime, I learned a lot of knowledge about flexo-printing, anilox roll engraving
and the operation of the laser treatment machines. Thank you Apex!
My internship timeline:
9-1 to 9-10: Keep learning a lot of new knowledge, feel a fulfilling life, learning practical
operations with nice people in the laser room.
9-10 to 9-20: Research preparation, find problems.
9-20 to 10-1: Experiments for laser cleaning, Hard time, not the same with the matlab
simulation tool and the theory. Slowly explore, try to find the solution by looking up articles
on the internet, asking my professor and the R&D staff in the company.
Best Survival Programs Laser Engraving Machine Home woodworking plans
4. Internship report in Apex – Han Jin
3
10-1 to 10-20: More experiments, more than 100 test burns, 5 rolls. Understand the effect of
each parameter and do trial and error. Finally found a proper set of parameters for laser
cleaning. Finishing the report of the laser cleaning part.
10-20 to 11-1: Theoretical learning of ceramic melting.
11-1 to 11-11: Experiments on post-melting of the ceramic, to clean the engraving dust and
make the surface smooth.
11-11 to 11-20: Write the post-melting part of the report.
11-20 to 11-30: Experiments on the roughness tests, finishing the last part of the report.
Best Survival Programs Laser Engraving Machine Home woodworking plans
5. Internship report in Apex – Han Jin
4
Summary
This report includes five parts:
The first chapter, introduction, introduces the general information about Apex and the process of
flexographic printing. In this part, different types of anilox rolls are described, including the representing
parameters. At last, there is a description of the three projects I did during the internship.
Second chapter is the preparation. Here I introduced the laser sources in Apex, and a simulation tool
called “Matlab Laser Toolbox” developed by professors in University of Twente, which could be used to
simulate the temperature profile of the material surface during laser treatment. For this tool, I also
introduced the thermal properties and light absorbance of the ceramic and inks. Unfortunately, this tool
was proved not suitable for the projects in Apex and was not used and shown in the final experiments and
report. I also developed an excel calculator to calculate the focus diameter of the laser beam. This excel
file would be attached in the final report package.
Chapter 3 is the design and results of the experiments for laser cleaning. The purpose of this project is
to use laser to clean the inks on the used anilox rolls, without damaging the ceramic surface and cell
structures. In this part, parameters of the laser treatment system – ES, BD, SA, SCL, DC, etc. – were tested
out and determined step by step, resulting in a final set of parameters that is suitable for laser cleaning.
At the end some improvements and prospects were proposed.
Chapter 4 is the design and results of the experiments for laser post-melting. The plan is to implement
laser post-melting just after the laser engraving, to replace finishing process. Same trial and error tests
were made to select out the most suitable laser treatment parameters. The results showed that with the
post-melting, the dust adhering to the ceramic surface would be blasted away by the laser beam,
achieving the same effect of the liquid cleaning. However, with the melting and re-solidification, even
though the top of the wall of the cells would be reshaped, the smoothness improvement was not obvious.
Therefore, using laser post-melting to replace the polishing process really would depend on the requests
of the customers.
Chapter 5 is about the project of the roughness change by laser treatment. The roughness
measurement device was introduced together with the measurement parameters. A series of comparison
tests were made to investigate the relation between the laser treatment and the roughness. Results
showed that most of the laser treatment could increase the surface roughness. With lower laser beam
power intensity, it is less possible that it would influence the roughness. And the different SCL (overlap of
the beam spots) has no obvious regulation to follow on influencing the change of the roughness. In
addition, the roughness of surface would increase obviously with the increase of melting level.
Experiments data, including the excel file “beam diameter calculator”, “Roughness test” data, all the
pictures and micro-images in the first two projects, would be arranged into a data package.
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Table of contents
Preface ............................................................................................................................................................2
Summary.........................................................................................................................................................4
Introduction ....................................................................................................................................................7
1.1 Flexographic printing.............................................................................................................................7
1.2 Anilox rolls.............................................................................................................................................9
Different shapes of the engraving:........................................................................................................10
1.3 Description of the projects .................................................................................................................11
Laser cleaning of the anilox roll ............................................................................................................11
Laser post-melting of the anilox roll after engraving............................................................................12
Surface tension and roughness changes after laser treatment ............................................................13
Chapter 2: Preparation..................................................................................................................................14
2.1 Simulation tool: Matlab Laser Toolbox ...............................................................................................14
2.2 Laser sources in Apex..........................................................................................................................14
2.3 Properties of the ceramic coating.......................................................................................................15
Thermal properties of the ceramic .......................................................................................................15
The absorbance and reflectance of the ceramic:..................................................................................16
2.4 Properties of the inks..........................................................................................................................17
2.5 Calculate the focus diameter of the laser beam.................................................................................18
Chapter 3 Design and results of the experiments for laser cleaning............................................................21
3.1 Determine the ES................................................................................................................................24
3.2 Determine the beam diameter (focus distance).................................................................................24
3.3 Determine the SA................................................................................................................................28
3.4 Determine the SCL ..............................................................................................................................28
3.5 The function of adjusting DC...............................................................................................................29
3.6 Testing trials for the selected set of parameters.................................................................................30
3.7 Conclusion and prospects...................................................................................................................33
Improvements and Prospects: ..............................................................................................................33
Chapter 4 Design and results of the experiments for laser post-melting.....................................................35
4.1 Determine the SA................................................................................................................................35
4.2 Determine the BD ...............................................................................................................................35
4.3 Determine the SCL ..............................................................................................................................37
4.4 Find the relation between ES and DC .................................................................................................38
4.5 Conclusion and prospects...................................................................................................................39
Chapter 5 Roughness changes after laser treatment....................................................................................40
5.1 Laser treatment effects on Ra.............................................................................................................44
5.2 Laser treatment effects on Rz.............................................................................................................44
5.3 Laser treatment effects on Rmax........................................................................................................45
5.4 Laser treatment effects on Rk.............................................................................................................46
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5.5 The effect of DC on the roughness change by laser treatment ..........................................................47
5.6 Conclusion for the roughness changes after laser treatment.............................................................48
References.....................................................................................................................................................50
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Introduction
APEX international is a manufacturer of precision coating- and ink-transfer technology products. Apex
supplies anilox/metering rolls and sleeves for label, flexible packaging, corrugated, offset and industrial
coating applications. Apex has production sites in the Netherlands, Italy, North America, South America,
and India. With manufacturing and sales operations on six continents in more than 80 countries, Apex
provides added value by supplying our customers with end-to-end anilox or GTT solutions (see later)
including measurement devices, cleaning and maintenance products, and educational/use-and-care
seminars. My internship place is at the home company Apex Europe B.V. in Hapert, the Netherlands.
Most of the products now in Apex are the anilox rolls and sleeves with ceramic coating on it. These
products are mostly used in flexographic printing.
1.1 Flexographic printing
Nowadays there are four commonly used printing technologies: Gravure printing, Flexographic
printing, Offset printing and Inkjet printing. Flexography (often abbreviated to flexo) is a form of printing
process which utilizes a flexible relief plate. It is essentially a modern version of letterpress which can be
used for printing on almost any type of substrate, including plastic, metallic films, cellophane, and paper.
It is widely used for printing on the non-porous substrates required for various types of food packaging (it
is also well suited for printing large areas of solid colour).
The greatest advances in flexographic printing have been in the area of photopolymer printing plates,
including improvements to the plate material and the method of plate creation. Digital direct to plate
systems have been a good improvement in the industry recently. Companies like Asahi Photoproducts, AV
Flexologic, Dupont, MacDermid, Kodak and Esko have pioneered the latest technologies, with advances in
fast washout and the latest screening technology.
Laser-etched ceramic anilox rolls play an important part in the improvement of print quality. By
adjusting the temperature of the anilox roll, the ink’s viscosity and therewith the amount of transferred
ink is controlled. Below is the working principle of the flexographic printing.
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Figure 1.1 Structure of the elements in flexographic printing.
Fountain roller
The fountain roller transfers the ink that is located in the ink pan to the second roller, which is the
anilox roller. In Modern Flexo printing this is called a Meter or "metering" roller.
Anilox roller
This is what makes flexography unique. The anilox roller meters the predetermined ink that is
transferred for uniform thickness. It has engraved cells that carry a certain capacity of inks that can only
be seen with a microscope. These rollers are responsible to transfer the inks to the flexible-plates that are
already mounted on the Plate Cylinders.
Doctor Blade (optional)
The doctor blade scrapes the anilox roll to ensure that the predetermined ink amount delivered is only
what is contained within the engraved cells. Doctor blades have predominantly been made of steel but
advanced doctor blades are now made of polymer materials, with several different types of beveled
edges.
Plate cylinder
The plate cylinder holds the printing plate, which is soft flexible rubber-like material. Tape, magnets,
tension straps and/or ratchets hold the printing plate against the cylinder.
Impression Cylinder
The impression cylinder applies pressure to the plate cylinder, where the image is transferred to the
substrate. This impression cylinder or "print Anvil" is required to apply pressure to the Plate Cylinder.
A flexographic print is made by creating a positive mirrored master of the required image as a 3D relief
in a rubber or polymer material. Flexographic plates can be created with analog and digital platemaking
processes. The image areas are raised above the non-image areas on the rubber or polymer plate. As
Figure 1 shows, the ink is transferred from the ink roll which is partially immersed in the ink tank. Then it
transfers to the anilox or ceramic roll (or meter roll) whose texture holds a specific amount of ink since it
is covered with thousands of small wells or cups that enable it to meter ink to the printing plate in a
uniform thickness evenly and quickly (the number of cells per linear inch can vary according to the type of
print job and the quality required) [1]. To avoid getting a final product with a smudgy or lumpy look, it
must be ensured that the amount of ink on the printing plate is not excessive. This is achieved by using a
scraper, called a doctor blade. The doctor blade removes excess ink from the anilox roller before inking
the printing plate. The substrate is finally sandwiched between the plate and the impression cylinder to
transfer the image [2]. The sheet is then fed through a dryer, which allows the inks to dry before the
surface is touched again. If a UV-curing ink is used, the sheet does not have to be dried, but the ink is
cured by UV rays instead.
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1.2 Anilox rolls
An anilox roll is a hard cylinder, usually constructed of a steel or aluminum core which is coated by an
industrial ceramic whose surface contains millions of very fine dimples, known as cells. Depending on the
design of the printing press, the anilox roll is either semi-submerged in the ink fountain, or comes into
contact with a so-called metering roller, which is semi-submerged in the ink fountain. In either instance, a
thick layer of typically viscous ink is deposited on the roll. A doctor blade is used to scrape excess ink from
the surface leaving just the measured amount of ink in the cells. The roll then rotates to contact with the
flexographic printing plate which receives the ink from the cells for transfer to the printed material.
Figure 1.2 An example of the anilox rolls
The characteristics of an anilox roll determine the amount of ink that will be transferred to the plate:
angle of the cells, cell volume, and line screen. Lower volume makes for less ink. Low line numbers will
allow for a heavy layer of ink to be printed, whereas high line numbers will permit finer detail in printing.
Both cell volume and line screen are closely correlated. It is essential for all flexo printers that the anilox
gives the correct ink density from the first print and stays consistent throughout the whole run regardless
of which cell structure or shape is used.
Line screen indicates the number of cells per linear inch on an anilox roll, and is a major component
when specifying an anilox roll.
Figure 1.3 Explanation of the line screen on an anilox roll [2]
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Line screen is chosen in direct correlation to anilox volume. For example, an anilox volume of 3.2
BCMs (billions of cubic microns), requires a line screen of approximately 500. If an anilox volume of 3.2
BCM was engraved at 1000 line screen, cells would be much too deep. In correlation, a 3.2 BCM anilox at
120 line screen anilox would result in cells being much too shallow. With increased ink strength and lower
anilox volumes, higher line screen anilox rolls can now be used. These higher line screen rolls give printers
the opportunity to reach for higher graphics with finer vignettes, line and type, and process work.
Following, is a rough outline of printing applications matched with appropriate line screens and cell
volumes:
Table 1.1 Outline of printing applications matched with appropriate line screens and cell volumes
Depending on the detail of the images to be printed, the press operator will select an anilox roll with a
higher or lower line screen. Low line screen rolls are used where a heavy layer of ink is desired, such as in
heavy block lettering. Higher line screens produce finer details and are used in four-color process work
such as reproducing photographs.
Different shapes of the engraving:
Laser engraving is the major method to engrave the microstructures on the anilox rolls. Different
types of the shapes are developed to meet the variant requirements and industrial standards already built
up. For example, by setting different parameters during the laser engraving, e.g. laser pulse frequency,
duty cycle, engraving speed, etc. the microstructures can be shaped into different types and angles like
Figure 1.4 and 1.5 shows.
Figure 1.4 Different shapes of the microstructure on the anilox roll from APEX[3]
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Figure 1.5 Different angles of the microstructure on the anilox roll [4]
Besides, one of the inventions from Apex is the GTT structure as Figure 1.6 shows. The GTT metering
rollers feature laser-cut slalom structured channels as opposed to the tradition hexagonal cells. According
to the Apex Group of Companies, this type of engraving is smoother as the laser is working as a constant
beam rather than through quick short bursts used to create the hexagonal cells. It can also make
shallower cells, which again helps the ink transfer to the plate.
Figure 1.6 GTT structure on the anilox roll from APEX
1.3 Description of the projects
There are a lot of possibilities on improving the production process related with laser. Different
improvements would be achieved by changing the laser power, processing velocity, pulse frequency,
shape of the laser beam, etc.
Laser cleaning of the anilox roll
Cleaning the anilox roll is an important part of the maintenance service from some production
companies. If the cells of the laser engraved ceramic anilox rolls become clogged with dirt, dried ink, or
coatings, print quality is affected. In normal use, the rolls must be cleaned as soon as possible after the
completion of a press run to remove residual ink/coatings.
Various cleaning methods can be applied, including chemical wash, Ultrasonic cleaning, media blast,
and laser cleaning, etc. [5] Through all these methods, laser cleaning as a relative new technology, can
evaporate foreign material on the ceramic surface but with no damage to the engraving. Meanwhile, it is
environment friendly.
The principle of technology is in the formation of a blast wave and it breaks the adhesion of any ink to
the surface of anilox rolls, as Figure 1.7 shows. High efficiency is due to the fact that the laser beam,
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focused to a spot, warms the layer of pollutant completely and the dried ink is completely removed from
the cells. None of the modern ways of deep cleaning can get the ink out of the bottoms of the cells of
rolls.
Figure 1.7 The principle of laser cleaning on the anilox cell
The purpose of this assignment is to use the laser source and operating system at Apex now, to
achieve a best and efficient result of laser cleaning. Our goal is to drive as much ink out as possible from
the roll and do not damage the roll in the meantime. This means, the temperature of the ceramic surface
should better < 500 °C but higher than 350 °C [6]. To control the temperature, we can do temperature
profile simulation by laser toolbox in Matlab (see chapter 2). The difficulties of this assignment are:
The Matlab simulation is based on a CW laser, while in Apex the laser for experiment is a CO2
pulsed laser. Although we can put average laser power into the program, but the practical results
could be very different with the simulation results.
There is no tool to know the diameter of the focused laser beam. To know it I need to measure
the machine and calculate.
The operating system of the laser and the roll is specifically designed for engraving cells, e.g.
hexagonal cells, so it is difficult to control the parameters as I want. Because for example if I
change the engraving speed, spontaneously the duty cycle and the pulse frequency will change.
Besides the temperature control, what we want is to have the good cleaning function with the
shortest time. Also the convenience for the operators needs to be considered. So in the first trial, we shall
operate on existed system and not change the optic devices also.
Laser post-melting of the anilox roll after engraving
The usual process after laser engraving is to move the roll to another machine and implement the
finishing process, which includes liquid cleaning and polishing. In the liquid washing and polishing process,
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the dust produced by the engraving process, which is adhere to the surface of the anilox cells, will be
washed away by the liquid cleaner. In the meantime, with the friction between the roll surface and the
polishing brush, the surface would become smoother, e.g. optical reflective on the surface, and also the
volume would become smaller to meet the requirement of the customers.
The problem of Apex now is the shortage of the finishing machines. This means the production chain
would be stuck at the finishing process. Rolls are always waiting at this step and would drag down the
whole production. Therefore, an idea about skipping the process of finishing could be tested.
The plan is to implement laser post-melting just after the laser engraving, without finishing process.
This could be fulfilled by installing another laser source on the laser engraving system. During the
engraving, the other laser source also starts the laser post-melting at a same beam speed. With the
treatment of the post-melting, the dust adhering to the ceramic surface would be blasted away by the
laser beam, achieving the same effect of the liquid cleaning. In addition, with the melting and re-
solidification, the top of the wall of the cells would be reshaped. The height of top would be lowered and
the thickness of it would be enlarged. This kind of change maybe will make the surface smoother and
then replace the process of polishing.
Another concern is the volume change before and after the post-melting. In normal cases, the volume
of the cells would be engraved to be about 1-3 BCMs larger than the requirement of the customer, and
then finished to be the required volume by the liquid cleaning and polishing system. If the finishing step
would be skipped, the relationship of the volumes before and after the post-melting needs to be found.
Surface tension and roughness changes after laser treatment
Laser heat treatment is always a good way to change the properties of the surface materials.
Properties that really matters in the anilox rolls are the surface tension and roughness, which are also
related with each other.
The plan is to use several kinds of laser beam to process the anilox roll, and compare the roughness
and surface tension changes, to see the effects of the beam properties. Because of the limit of the
internship time and equipment, the roughness would first be measured and compared.
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Chapter 2: Preparation
2.1 Simulation tool: Matlab Laser Toolbox
Matlab® is high-level interpreted language and interactive environment for algorithm development,
data visualization, data analysis, and numeric computation, developed by MathWorks Inc. Add-on
toolboxes, which are collections of special-purpose Matlab functions and scripts, extend the Matlab
environment to solve particular classes of problems.
The Matlab Laser Toolbox [7] provides several functions and scripts for analysis and visualization of
laser beam properties, as well as, functions to calculate the interaction (e.g. induced temperature by
absorbed laser energy in a solid) in a material.
The function tsurfsrc (Temperature of a SURFace heat SouRCe), of the Matlab Laser Toolbox allows the
calculation/simulation of the temperature field T(x,y,z,t) in a solid, due to absorbed laser energy at the
surface of a material (with semi-infinite dimensions), of a laser beam with a power density profile I(x,y),
moving at v [m/s]. As such it can be used as a simulation tool for the surface temperature of the laser
processing ceramic (neglecting an impact of ink and a roll microrelief due to their shallow thickness and
to a low contribution to energy consumption at multipulse processing accordingly).
2.2 Laser sources in Apex
There are two types of laser sources in Apex.
The first type is IPG's YLR-LP Series. These 10W to 500W CW single mode linearly polarized Yb fiber
laser systems are coordinated with highly precise machines used for engraving the anilox rolls. It has 1060
to 1080nm wavelength range and TEM00 (M2
<1.1) beam quality.
The second type is a liquid-cooled, RF-excited OEM Industrial CO2 Laser, Diamond E-150 from
Coherent. The properties of this laser source are listed below at Table 2.2.
Specifications Values
Wavelength (μm) 10.2 to 10.8
Pulse Frequency (kHz) Single-shot to 100
Maximum Duty Cycle (%) 70
Output power range (W) 20 to 150
Peak Effective Power (W) 375
Pulse Energy Range (mJ) 5 to 315
Pulse Rise/Fall Time (μsec) (at 1 KHz and 35% duty cycle) 50 typical
Mode Quality (M2
) ≤ 1.2
Polarization (Parellel to baseplate) Linear >100:1
Beam Waist Diameter (1/e2
) (mm) 2.2 typical
Beam Divergence (Full-angle) (mrad) 6.6 typical
Beam Divergence Ellipticity 1:1.2
Table 2.1 System specifications of the CO2 laser source, DIAMOND™ E-150, Coherent
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This laser is connected with a much older engraving machine, which is less precise in engraving, and
also used for post melting or roll cleaning experiments. During the internship, I will mostly use this laser
source and engraving machine to do the experiments.
2.3 Properties of the ceramic coating
Chromium oxide Cr2O3 thin films have wide variety of technological applications. This oxide exhibit
high hardness and high wear with corrosion resistance which is important properties for protective
coating applications [8]. Cr2O3 adopts the corundum structure, consisting of a hexagonal close packed
array of oxide anions with 2/3 of the octahedral holes occupied by chromium. Similar to corundum, Cr2O3
is a hard, brittle material (Mohs hardness 8-8.5). It is not readily attacked by acids or bases, although
molten alkali gives chromates. It turns brown when heated, but reverts to its dark green color when
cooled. It is also hygroscopic [9].
The coating layer of the anilox roll from Apex is all consisted of 99.7% pure Cr2O3. The coating
method is thermal sprayed plasma coating. The width of the ceramic layer depends on the screen of the
structure, most of which are between 0.1-0.4mm, with 90% 0.1-0.15 mm.
Thermal properties of the ceramic
In the laser toolbox program, the thermal properties of the operating surface needs to be filled in.
Cr2O3 physical and mechanical properties represented in Table 2.2 were taken from the technical
reference handbook of manufacturing company of plasma coatings.
Table 2.2 Cr2O3 physical and mechanical properties [10].
From Table 1, we can know when the operating temperature of Cr2O3 is under 500 °C: Density: ρ =
5210 kg/m3
; Thermal heat capacity: Cp =860 [J/(kg*K)]; Thermal diffusivity: κ = 2.23 * 10-6
[m2
/s]; Thermal
conductivity: k = 10 [W/(m*K)]. Besides: Melting temperature: 2,708 K / 2435 °C; Refractive index: n =
2.551.
However, the properties of the ceramic will change when the temperature grows. When the project is
going to melt the ceramic, the properties would be different.
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The absorbance and reflectance of the ceramic:
Undoped and Iodine (I)–doped chrome oxide (Cr2O3) thin films have been prepared by chemical spray
pyrolysis technique at substrate temperatures (773K) on glass substrate [11]. The reflectance of the pure
Cr2O3 at different wavelengths is shown in the figure below.
Figure 2.1 Reflectance spectra against wavelength of the undoped and I–doped (Cr2O3) thin films.
Usually, by detecting a thin film of a material, there are Absorbance (A), Reflectance (R) and
Transmittance (T). In our case, because the substrate is not transparent, plus the power may be not strong
enough to penetrate the whole ceramic layer, therefore (A+T) = (1-R), which means (1-R) is the
absorbance of the ceramic layer.
According to another reference [11], the light reflectance of the Cr2O3 thin film based on stainless steel is
shown below.
Figure 2.2 Reflectance curves for iron and chromium oxides on stainless steel. The oxide thicknesses chosen were: Fe2O3: 58
nm, Fe3O4: 70nm and Cr2O3: 80 nm.
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As shown, the reflectance curve is analogical as the curve according to Figure 2.1. The data is based on
the experiment that for the thin film of Cr2O3 (less than or around 1 μm), which is not the same with our
case (usually the ceramic layer on the roll is mostly 0.1-0.15 mm deep, and it is sprayed on a Nickel layer
by thermal sprayed plasma coating). But because of the same material, we can assume the same
reflectance could be applied on the Cr2O3 of the anilox roll. Another reason could be the color of Cr2O3 is
dark green, if comparing with Fig (), in the spectrum of visible light (about 390 to 700 nm), the maximum
reflected wavelength is 400 to 500 nm, in which the spectrum of dark green is from.
2.4 Properties of the inks
Usually there are three kinds of common used inks: UV ink, Water-based ink and Solvent ink.
Over 90 percent of inks are printing inks, in which colour is imparted by pigments rather than the dyes
used in writing inks. Pigments are insoluble, whereas dyes are soluble, though sometimes these terms are
used interchangeably in commercial literature. Ink pigments are both inorganic and organic. For example
the well-known blue pigment copper phthalocyanine blue is PB 15. Others could be yellow (azo pigment),
magenta (lithol pigment), cyan (copper phthalocyanine), etc. Most white inks contain titanium dioxide as
the pigment, as rutile and anatase in tetragonal crystalline form.
The boiling point is the most crucial property when choosing suitable solvents. For printing inks, the
following boiling point ranges are common:
Figure 2.3 Boiling points of the printing inks
Figure 2.4 Absorbance curves for different pigments against wavelength
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Figure 2.4 shows the absorbance curves for some pigments at different wavelengths. In general, Nd
YAG lasers at the fundamental 1.064 μm wavelength (So as the Yb fiber lasers in Apex, IPG's YLR-LP Series)
are best suited for marking metals while the CO2 laser is more suited for plastics, painted or organic
marking. According to reference [12], YAG laser does not work well on organic materials, including some
organic pigments, while even a low powered CO2 laser is very effective at removing paint from most metal
surfaces, which means in some level, the pigments of the ink could absorb more energy from CO2 laser
than YAG laser because of the wavelength differences. Also according to Figure 2.2, the reflectance of the
ceramic at 10.6 μm is much larger than at 1.06 μm. Therefore, to remove the ink without damaging the
ceramic, CO2 laser at wavelength 10.6 μm is a better choice than the Yb fiber laser at wavelength 1.06 μm.
In my experiments, five kinds of inks were used for experiments: water-based white ink, water-based
red ink, solvent white ink, solvent red ink, and water-based blue ink. As shown in figure 2.5, the inks were
averagely covered on a roll for test.
Figure 2.5 Inks on the roll for preparation of the laser cleaning tests
2.5 Calculate the focus diameter of the laser beam
Lens specification: SLZS2-19-50.8PCO2
Diameter: 19.05 mm
Focal length: 50.8 mm / 2 inches
Back focal length: 49.0 mm (The distance from the final optic within a system to the rear image point
of the system)
According to the lecture notes by G.R.B.E. Romer, after the focus of the beam,
d1 =
4
𝜋
𝜆𝑓
𝐷
Where d1 is the diameter of the focus, λ is the wavelength of the laser, D is the diameter of the beam
before focus, f is the focal length of the lens.
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The diameter of the focused laser beam along the optical axis can be described as
d(z)2
= 𝑑𝑓
2
+ 𝜃𝑓
2
(𝑧 − 𝑧0𝑓)2
where df [m] is the diameter of the focus, θf [rad] is the full far field divergence angle of the focused
beam, and z0f [m] the location of the focus relative to a reference location. And
𝜃𝑓 = 𝑡𝑎𝑛−1
(
𝐷
𝑓
) ≈
𝐷
𝑓
if 𝐷 ≪ 𝑓
The way to measure the D is to put a plastic plate, which is specific for this measuring purpose, in
front of the laser beam for a while, and measure the melted area. As Figure 2.6 shows, D is measured to
be 9 mm. After knowing this, an excel form for calculation was made as shown below.
Figure 2.6 Melted plastic plate for measuring the beam diameter before focus
parameter value unit remark
D 9 mm Beam diameter before focal lens
f 50.8 mm Focal length of the lens
θf 0.175345902 rad
Full far field divergence angle of the focused
beam
d(f) 86 um Diameter at the focus
d(z) 600 um Diameter of the beam on the ceramic surface
∆z 3.386475959 mm Radial distance between the beam at d(f) and d(z)
y1 5.296475959 mm
Number of distance that should be set on the
clock if use an adjusting shim that has a thickness of
15mm (1.91mm + ∆z )
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y2 0.296475959 mm
Number of distance that should be set on the
clock if use an adjusting shim that has a thickness of
10mm (1.91mm + ∆z - 5mm)
Table 2.3 Laser beam properties calculation
For the special setup in Apex, when installing the lens, if you use an adjusting shim that has a
thickness of 15mm, the beam focus would be achieved at a radial distance of 1.91mm on the clock in the
specific CO2 laser system "Zedco". That means, for example, if you want to get a beam diameter of d(z) =
600 μm, and the thickness of the adjusting shim is 15mm, then the number of the radical distance on the
clock should be set to be y1 = 1.91 + ∆z = 5.296 mm, as shown in table 2.3. In addition, if the the thickness
of the adjusting shim is 10mm, then the number of the radical distance on the clock should be set to be
y2 = 1.91 + ∆z – 5mm = 0.296 mm. The rest can be done in the same manner.
Table 2.4 shows some typical values that the operators could use.
BD (μm) Thickness of the adjusting shim (mm) Distance values on the clock (mm)
86 (minimum) 15 1.910
100 15 2.201
200 15 2.940
400 15 4.138
600 15 5.296
800 15 6.450
1000 15 7.592
1000 10 7.592-5 = 2.592
1200 10 3.736
1400 10 4.879
1600 10 6.022
1800 10 7.164
1800 5 7.164-5 = 2.164
2000 5 3.305
Table 2.4 Distance values on the clock according to different BD required (calculated by the excel file)
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Chapter 3 Design and results of the experiments for laser cleaning
To design the experiments, first the working principle of the engraving system needs to be understood.
As Figure 3.1 shows, during the engraving, the anilox roll will be fixed and turn around the center shaft
at a certain velocity. In the meantime, the laser beam is located as vertical with the center shaft and move
along the parallel direction with the center shaft of the anilox roll. With this mechanical system, the cells
produced by the laser pulse can be distributed uniformly on the surface of the whole roll.
Figure 3.1 CO2 laser engraving system in Apex
In the ALE engraving processing system, when inputting some parameters, other parameters will
change to fulfill the need of engraving a serious of decent cells. First there are explanations about these
important parameters:
ES (Engraving Speed)
The ES (Engraving Speed) is the circumferential speed at which the surface of the roller passes the
engraving nozzle. This speed is normally specified in cm/second.
RD (Roller Diameter)
The RD (Roller Diameter), is the diameter of the roller, usually specified in millimetres.
DC (Duty Cycle)
The DC (Duty Cycle), is the ratio of ‘On’ to ‘Off’ time of the laser pulse expressed as a percentage.
PF (Pulse Frequency)
The pulse frequency of the laser source. Details can be found in Figure 3.2.
PL (Pulse Length)
The PL (Pulse Length), is the length of the laser pulse.
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Figure 3.2 Anilox pulse details
SA (Screen Angle)
The SA is the ‘Screen Angle’ of the anilox cells, measured in degrees. Examples are shown below:
Figure 3.3 Anilox screen angle examples
SCL / SCLI (Screen Count Linear)
The SCL (Screen Count Linear), is the number of cells per centimetre, whilst SCLI is the number of cells
per inch.
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Figure 3.3 Anilox SCL example
For the convenience of the operation and also the safety of the machine and system, using the existed
engraving system (while changing some parameters to make it suitable for cleaning) is then the first
option. For understanding, below is some data transformation (assume the diameter of the roll is 150mm,
the length of the roll is 1000mm.)
Table 3.1 Parameters change in the ALE engraving system
1. At the same SA (Screen Angle, °) and ES (Engraving Speed, m/s), with the increase of SCL, the pulse
length PL is the same, which means the energy used to engrave a cell is the same.
2. The SA and SCL determine the cell distance, which will determine the relation between ES and PF.
Vertical cell distance = ES * 1/PF.
3. From the finish time, we know the time increases with the increase of the SCL, and also the increase
of the SA, and the decrease of speed. To understand this, with the increase of the SCL and SA, the
intensity of the cells in the axis direction of the roll increases, i.e. the decrease of the EPR (Engraving
Pitch Rate), which means the axis speed of the roll will decrease, resulting the increase of processing
time.
ES [m/s]
SCL
[l/cm]
SA 60° SA 10°
DC [%] PF [kHz] Finish t DC [%] PF [kHz] Finish t
0.05
50 0.5 0.144 12.5 0.720
20 0.2 0.058 5 0.288
10 0.1 0.029 2.5 0.144
0.1
50 1.0 0.289 13’6’’ 24.9 1.440 6’39’’
20 0.4 0.116 10 0.576
10 0.2 0.058 2’38’’ 5 0.288 1’20’’
0.5
50 25 1.444 2’38’’ 124.7 7.199 1’20’’
20 10 0.578 49.9 2.879
10 5 0.289 0’32’’ 24.9 1.439 0’16’’
1.0
50 50 2.887 249.4 14.397
20 20 1.155 99.7 5.758
10 10 0.578 49.9 2.879
2.0
50 100 5.774 498.7 28.794
20 40 2.311 199.5 11.516
10 20 1.157 99.7 5.757
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4. At certain ES, with the increase of SA, PF decreases, which means the intensity of the cells in one
circle of the roll decreases, whist in the meantime the intensity of the cells along the shaft increases.
At 45°SA, the cells are most averaged distributed.
For us, to clean the roll, we want the processing cells to be as many as possible to cover and even
overlap the area of the ink, which means higher SCL and a proper SA. But in the meantime, the processing
time will increase obviously. Therefore, there is always a compromise between the cleaning effects and
the processing time.
The plan of the experiment is to do a series of comparison experiments, step by step, to test out the
best set of parameters for the practical laser cleaning of the anilox rolls. ES, SA and SCL will determine PF.
With DC, PF and DC will then determine the PL. Together with ES and PL, they will determine the energy
that is put into cell on the ceramic surface, which is the most important judgment on whether the ceramic
would be damaged or not.
3.1 Determine the ES
In ideal case, to get the best production efficiency, the higher the speed, the shorter the cleaning
time would be. However, due to the mechanical limitations of the engraving system, the top ES you
can type in the engraving system is 250 cm/s. In addition, in case of safety, it is not allowed to have a
very high angular speed of the roll. For rolls that has diameter below 100mm, the engraving speed
below 200 cm/s is required.
Because for convenience, an uniform set of parameters is needed. So for safety concern (for rolls
that have larger diameters, higher speed is possible), the engraving speed is chosen to be 150 cm/s.
3.2 Determine the beam diameter (focus distance)
According to section 2.5, the relation between the beam diameter and the focus distance would be
known. So the operators here can adjust the beam diameter to a certain value freely.
According to the principle of laser cleaning stated in section 1.3, the blast wave will break the
adhesion of any ink to the surface of anilox rolls, which requires a certain amount of power intensity to
provide the enough thermal and mechanical effect. In practical experiments, if the power intensity is not
enough, i.e., the beam diameter is not small enough, then the adhesion between the ink and the ceramic
would not be broken and the inks would not be totally evaporated and pushed out.
Comparisons between some tests can explain the importance of the laser power intensity. Tests 62, 63
and 64 in Figure 3.1 were using the typical post-melting parameters which were developed by operators
in Apex:
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62: ES = 170 cm/s, DC = 41.4, PF = 9.617 kHz, SA = 7°, SCL = 57, BD (beam diameter) = 550 μm.
63: ES = 170 cm/s, DC = 41.4, PF = 9.617 kHz, SA = 7°, SCL = 57, BD = 460 μm.
64: ES = 170 cm/s, DC = 41.4, PF = 9.617 kHz, SA = 7°, SCL = 57, BD = 380 μm.
And also, most of the tests in Figure 3.2, BD = 1800 μm. It can be seen that with a big beam diameter
(low power intensity), even though the speed was low and all the ink and ceramic were melted, there was
still the trace of the ink on the ceramic (black and yellow). This is because the laser intensity was not high
enough to create the blast wave to shock the ink away. In addition, once the black and yellow melted
substances were produced, even if you use the highest power intensity, you will not remove them, which
means these substances are much more difficult to clean than the normal inks.
Figure 3.1 Tests on a roll covered by solvent red and blue ink (numbers are experiments marks by which microstructures can
be found in the pdf files)
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Figure 3.2 Tests on a roll covered by water-based white and red ink (numbers are experiments marks by which
microstructures can be found in the pdf files)
65: ES = 100 cm/s, DC = 15, SA = 45°, SCL = 150, BD = 200 μm.
66: ES = 150 cm/s, DC = 12, SA = 45°, SCL = 150, BD = 200 μm. (Ceramic not melted, left red, blue and
white ink.)
67: ES = 150 cm/s, DC = 12, SA = 45°, SCL = 150, BD = 200 μm. 3 times repeat. (Ceramic not melted, red
and blue ink well cleaned, left white ink.)
68: ES = 150 cm/s, DC = 8, SA = 45°, SCL = 200, BD = 100 μm. (Ceramic not melted, left red, blue and
white ink.)
69: ES = 150 cm/s, DC = 8, SA = 45°, SCL = 200, BD = 100 μm. 3 times repeat. (Ceramic not melted, red
and blue ink well cleaned, left little white ink.)
70: ES = 150 cm/s, DC = 9, SA = 45°, SCL = 200, BD = 100 μm. 4 times repeat. (Ceramic little melted, red,
blue and white ink well cleaned)
As the results shows, there is a range of the BD, in which the laser beam is powerful enough to blast
away the dry ink, and while BD is not too small to ablate the ceramic:
If the BD is too big. The advantage would be with a proper SCL, a bigger BD allows the beam to
clean the same place of the roll for more than one time, which means less left ink (you can see
the left ink on the test 68 in Figure 3.1). The disadvantage would be that the area of the low
power intensity laser beam would be relatively large and the resulting melted ink (yellow and
black substances sticking to the ceramic as shown in 27, 28 in Figure 3.2) would be very difficult
to clean.
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If the BD is too small. The advantage would be a very small low power intensity area, dry ink
would be easily blasted away and the melted ink would barely stick on the ceramic surface. The
disadvantage would be that after cleaning one circle of the roll, a part of the melted ink would be
pushed aside and accumulated on the next circle, then one time cleaning is not enough, resulting
the left ink (see 66, 68). Also a small BD needs a larger SCL for a fully cover of the cleaning,
meaning longer cleaning time.
The smallest BD of the system is 86 μm. According to experiments 53-61 (see pdf), with the control of
DC, the minimum BD would not damage the ceramic. In the meantime, after a series of tests in Figure 3.1,
the upper BD was found to be 200 μm. The testing way is to see after cleaning, whether the ink would be
left with melted yellow and black substances.
Among the three inks of different colors, the white ink is the most difficult one to be cleaned, mostly
because of its low light absorbance and heavy TiO2 particles. According to tests 67, when BD=200 μm,
even after 3 times cleaning, the cleaning results of the white ink was still not good. See the
microstructure of the test 67 after cleaning.
Figure 3.3 Microstructures of test 67 after cleaning. (a) Original area (a little dirty); (b) Blue solvent ink; (c) Red water-based
ink; (d) White water-based ink.
At the minimum BD, the white ink could be well cleaned, see test 60 and 61. Considering the production
time, the BD was finally set to be 100 μm. According to test 69 and 70, with a proper DC, the results were
acceptable, see Figure 3.4 and 3.5.
Figure 3.4 Microstructures of test 69 after cleaning. (a) Original area (a little dirty); (b) Blue solvent ink; (c) Red water-based
ink; (d) White water-based ink.
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Figure 3.5 Microstructures of test 70 after cleaning. (a) Original area (a little dirty); (b) Blue solvent ink; (c) Red water-based
ink; (d) White water-based ink.
For BD = 100μm, the number of the radical distance shown on the clock should be set to be 2.201mm if
an adjusting shim of 15mm thickness were used, as table 3.2 shows.
parameter value unit remark
D 9 mm Beam diameter before focal lens
f 50.8 mm Focal length of the lens
θf 0.175345902 rad Full far field divergence angle of the focused beam
d(f) 86 um Diameter at the focus
d(z) 100 um Diameter of the beam on the ceramic surface
∆z 0.291021362 mm Radial distance between the beam at d(f) and d(z)
y1 2.201021362 mm
Number of distance that should be set on the clock if use an
adjusting shim that has a thickness of 15mm (1.91mm + ∆z )
Table 3.2 Laser beam properties calculation when BD = 100μm
3.3 Determine the SA
As stated before, at certain ES, with the increase of SA, the intensity of the cells in one circle of
the roll decreases, whilst the intensity of the cells along the shaft increases. At 45°SA, the cells are
most averaged distributed. For cleaning, we want the laser beam to averagely cover the ink, so 45°is
the best choice. However, smaller SA means shorter production time. Compromises could be made
in the future to meet the cleaning request while improving the production speed by decrease the SA.
3.4 Determine the SCL
BD, SA, and SCL together will determine the type of the beam cover on the ink. At least, the beam
spots should be overlapped in order to cover the whole ceramic surface. First, SCL=200 l/cm was chosen,
which means the distance between two cells along the circle is
10000
200
∗ √2 = 70.7μm. For BD=100 μm, the
ceramic surface can be well covered, see Figure 3.6.
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Figure 3.6 Overlap of the laser beam during test if SCL=200 l/cm, BD=100 μm.
Next, a series of comparison tests had been done:
(1) ES = 150 cm/s, DC = 8.5, SA = 45°, SCL = 200, BD = 100 μm. (Ceramic not melted, left red, blue and
white ink. After the second cleaning, all the ink could be well cleaned.)
(2) ES = 150 cm/s, DC = 9, SA = 45°, SCL = 250, BD = 100 μm. (Ceramic a little melted, cleaning results
worse than (1).)
(3) ES = 150 cm/s, DC = 11, SA = 45°, SCL = 400, BD = 100 μm. (Ceramic a little melted, cleaning results
worse than (2).)
(4) ES = 150 cm/s, DC = 11, SA = 45°, SCL = 600, BD = 100 μm. (Ceramic a little melted, cleaning results
worse than (3).)
From the tests, we can see the overlap is not the more, the better. The reason may be that with the
higher SCL there would be higher PF, making it more like a CW laser. Too overlapped and a shorter pulse
duration would make the ink difficult to be blasted away. This is why in test (2) (3) (4), even though the
ceramic were melted, the cleaning results were still worse than (1). Therefore, SCL=200 l/cm is a good
choice.
3.5 The function of adjusting DC
ES, SA and SCL determine the PF, then PF and DC determine the PL, which determines the energy
that is put into the ceramic per laser pulse. Every different set of parameters has a critical value of
DC that would just melt the ceramic. That DC would provide the most potential of cleaning the ink
while not melting the ceramic. Most of the DC values used in my experiments are this critical value.
This DC could be found by doing series of tests or by computer simulation in the future.
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For our particular set of parameters: ES = 150 cm/s, SA = 45°, SCL = 200, BD = 100 μm, PF = 21.214
kHz, PL = 4 μs. The best DC would be between around 8.5. Due to different practical cases, the DC could
be between 8.0 – 9.0.
3.6 Testing trials for the selected set of parameters
The selected set of parameters: ES = 150 cm/s, SA = 45°, SCL = 200, BD = 100 μm, PF = 21.214
kHz, PL = 4 μs, DC = 8.5.
In addition, one important step before laser cleaning is to use liquid cleaner, try to mix the inks and
make the ink layer smooth and have average thickness.
(1) Put some liquid cleaner on the tissue;
(2) Press the tissue on the running roll and go through the roll, hold longer time when you feel unsmooth
lumps and try to clean it off.
(3) Repeat the process for one or more times.
Figure 3.7 A testing roll before and after liquid cleaning.
The process can be seen in Figure 3.7. There are two reasons for doing this. First one is to decrease
the possibility of remaining ink lumps. Because if the ink layer is too thick in some places, the laser power
would not be enough to clean it just by one or two times. The second reason is that some rolls are
covered with different inks, mixing the inks would average the light absorbance of the inks and make the
cleaning more efficient.
After the pre-cleaning process, laser cleaning treatment can be used afterwards. Figure 3.8 shows the
test result using the selected set of laser cleaning parameters on the roll from Figure 3.7. The inks covered
include five kinds of inks: water-based white ink, water-based red ink, solvent white ink, solvent red ink,
and water-based blue ink.
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Figure 3.8 Test results using the selected parameters for 1, 2 and 3 times.
As can be seen in Figure 3.8, one time cleaning is not enough for this situation, there are left ink on
the roll by three kinds of inks. This is because the ink layer was thick and also as stated before, part of the
ink that was blasted away would accumulate on the neighbour and left an ink lump.
Therefore, a second even more times are needed for well cleaning. In theory, the more times it goes
through, the cleaner it would be. For production efficiency, a third time is not allowed. Figure 3.9 shows
the microstructure of the test 71.
71: ES = 150 cm/s, SA = 45°, SCL = 200, BD = 100 μm, PF = 21.214 kHz, PL = 4 μs, DC = 8.5. Twice.
Figure 3.9 Microstructures of test 71 after cleaning. (a) Original area (a little dirty); (b) Blue solvent ink; (c) Red water-based
ink; (d) White water-based ink.
As can be seen, by twice cleaning, most of the inks can be well cleaned, except the white ink, still a bit
worse than the result in Figure 3.5. To ensure the effectiveness of the two time laser cleaning, volumes of
the roll were measured:
Volume before cleaning: 5.46 BCMs;
Volume after cleaning (red ink 1 time): 6.20 BCMs;
Volume after cleaning (red ink 3 time): 6.09 BCMs;
Volume after cleaning (white ink 2 time): 6.03 BCMs;
Volume after cleaning (white ink 3 time): 6.23 BCMs;
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After 2 times cleaning, the volume of the cells covered by white ink is already similar with the other
clean places on the roll. If the customer were not satisfied, then it needs more times cleaning.
When cleaning the white inks, it is inevitable that there would be left inks and the test in my
experiments is an extreme example because the roll was totally covered by big area of pure white ink.
Common dirty rolls are covered with different kinds of mixed inks and the layer is relatively thin because
the customer would had already used some chemical cleaning methods for reuse, which could be easier
to clean and sometimes one time laser cleaning is enough.
Different kinds of dirty rolls in Apex were collected and cleaned by using the selected set of
parameters. The microstructures of the rolls include GTT, 60°, 30°, and Helical, etc.; The type of SCL varies;
The type of inks also varies . The results show that all the rolls would be relatively clean without damaging
the ceramic after 2 times laser cleaning, some of them only need 1 time. Below are some pictures
showing the cleaning results.
Figure 3.10 shows a roll with a helical structure that is originally covered with black ink. Different inks
were then covered on purpose. After pre-cleaning process and one time laser cleaning, the roll is already
pretty clean.
Figure 3.10 Comparison before and after laser cleaning. Helical structure covered with black ink. 1 time.
Figure 3.11 shows a roll with a 60° structure that is originally covered with thick blue ink. Different
inks were then covered on purpose. After pre-cleaning process and two times laser cleaning, the roll is
already pretty clean. At the first time laser cleaning, because of the thickness of the ink, there were left
ink on the roll. The second cleaned all of the inks including the white inks because with the blue inks
under, the laser energy would be better absorbed by the ink and it was easier to be cleaned.
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Figure 3.11 Comparison before and after laser cleaning. 60°structure covered with blue ink. 2 times.
3.7 Conclusion and prospects
According to the selection process and trial experiments, a set of parameters was screened out to be
used as laser cleaning parameters:
ES = 150 cm/s, SA = 45°, SCL = 200, BD = 100 μm, PF = 21.214 kHz, PL = 4 μs, DC = 8.5. No limit times.
If an adjusting shim of 15mm thickness were used, the number of the radical distance shown on the
clock should be set to be 2.201mm.
In practical, operators can slightly adjust the value of DC to adapt to the real situations, in case the DC
would be too large to melt the ceramic.
By simple chemical pre-cleaning, this set of parameters is suitable for cleaning all kinds of rolls which
are covered with different inks without damaging the ceramic. Theoretically, the more times the laser
cleaning is through, the cleaner the roll would be. Practically, 2 times is enough for usual rolls (depending
on the request of the customers).
Improvements and Prospects:
1. The beam profile is Gaussian. If the profile could be changed into top-hat, the laser power intensity
would be averagely distributed and there would be less possibility to cause the melted left inks
(yellow and black substances, difficult to clean). Then the BD could be enlarged, which means smaller
SCL is possible and shorter production time could be achieved.
2. For other colour inks except white ink, smaller laser power intensity is enough and the BD could be
larger than 200 μm, which means smaller SCL is possible and shorter production time could be
achieved. So one possibility is to set two groups of parameters, one is for white ink, one is for other
inks, which can save a lot of cleaning time.
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3. Running the laser cleaning with 2 or more laser beams at the same time would largely improve the
cleaning efficiency and quality. In some professional cleaning companies, the cleaning laser is a line
consisted of several laser beams, which means 1 time equals several times cleaning. By installing
more laser beam and running at the same time, the cleaning procedure would only be needed to run
for one time, and the roll would be totally clean.
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Chapter 4 Design and results of the experiments for laser post-
melting
4.1 Determine the SA
The principle of the laser post-melting is similar with the laser cleaning. When melting the cells, we
want the beam spots to be averaged distributed on the surface and have minimum visible influences. Still,
as the reasons stated before, SA = 45° seems to be the best choice.
4.2 Determine the BD
The principle of determining the BD is the same with the laser cleaning case – BD should be small
enough to provide high laser power intensity to blast away the ceramic dust. In the meantime, the
intensity should not be too strong to damage the top wall of the cells. And considering the production
efficiency, the BD should be as large as possible to get lower SCL and higher EPR (Engraving Pitch Rate),
which means lower processing time.
Here is an example (see pdf “Han – 92”) showing the micro images before and after the post-melting.
As can be seen, before the melting, the dust from the engraving is fully covered on the surface. With the
post-melting, most of the dust could be cleaned away. In addition, with a bit melt and re-solidification,
the top of the cell wall became shinier.
Figure 4.1 Comparison between the micro images before and after the post-melting
A roll with GTT structure was chosen. A series of experiments were done on this roll for testing the
proper BD. Figure 4.2 shows a comparison between a) the original surface after air blowing and b) the
surface after normal finishing process. As shown, after liquid washing and polishing, both the top and
bottom of the surface would be quite flat and smooth compared to the original one just after engraving.
To reach the result as Figure 4.2 b) shows by the post-melting is our goal.
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Figure 4.2 Comparison between a) the original surface after air blowing and b) the surface after normal finishing process.
Different BD was implied on the same ceramic surface for comparison. The original sample, Volume:
4.16 BCMs; Depth: 10.10 μm.
80: Laser cleaning parameters. ES = 150 cm/s, SA = 45°, SCL = 200, BD = 100 μm, DC = 8.5. After treatment,
Volume: 4.44 BCMs; Depth: 10.79 μm.
83: ES = 150 cm/s, SA = 45°, SCL = 50, BD = 400 μm, DC = 15. After treatment, Volume: 4.05 BCMs; Depth:
9.59 μm.
84: ES = 150 cm/s, SA = 45°, SCL = 50, BD = 600 μm, DC = 25. After treatment, Volume: 4.24 BCMs; Depth:
9.78 μm.
88: ES = 150 cm/s, SA = 45°, SCL = 50, BD = 1000 μm, DC = 45. After treatment, Volume: 4.17 BCMs; Depth:
9.61 μm.
Figure 4.3 shows four micro images using different BD and a critical DC which makes the ceramic a bit
melted. From the images, we can see that all the four images are not as flat and smooth as the one after
normal finishing process. In fact, in macroscopic view, if you use a blade to slightly scrape the surface, you
can judge the roughness by the feeling from the blade. The finished surface is smooth, and has optical
reflection. While the original surface is relatively rough and have no optical reflection, and the ones after
post-melting have similar roughness, just a little smoother than the original one. This means, using the
post-melting method could not achieve the smoothness as normal finishing process could achieve.
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Figure 4.3 Micro images using different BD and a critical DC which makes the ceramic a bit melted. a) Test 80. b) Test 83. c)
Test 84. d) Test 88.
Among the four images, it can be seen that the surface from “(c) Test 84” has the best shape,
considering the remove of the dust and the damage of the cells wall. When the BD = 1000μm, as “d) Test
88” shows, the laser intensity is not strong enough to blast away all the dust covered, leaving a coarse top
surface. In the meantime, when BD = 100 or 400μm, there is a large possibility that the wall would be
damaged by the high intensity of the laser. Overall, it turns out that BD = 600μm is a good choice for the
post-melting process.
4.3 Determine the SCL
If the relation between the BD and SCL would be the same with the one in the laser cleaning process,
as Figure 3.6 shows, if the BD = 600μm, the SCL would be 33.33 l/cm. Through the test 94 and 97 (see pdf),
the result from the microscopic image is acceptable. However, from the macroscopic view, because of the
SCL is low and also the relatively high DC for melting, visible 45°engraving cells would be observed,
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which is not allowed. Therefore, larger SCL is needed to increase the coverage rate of the laser beam on
the surface, to prevent the uneven distribution of the melt area. After tests, SCL = 50 l/cm seems to be a
good choice.
If in the future, there are still optical side effects on the surface, then the measure would be increase
the BD, i.e., increase the value on the “focus clock”, and in the meantime increase the SCL.
4.4 Find the relation between ES and DC
In different engraving cases, the ES would be different. Therefore, to adapt the post-melting
system into the engraving system, the ES of the post-melting is required to be the same with the ES
of the engraving. In order to have the same melting effect at different ES, a form was made for the
convenience of the operators. See Table 4.1, corresponding to one ES, there is a range of DC provided
for the operators to adjust in case of practical situations (the DC value in the bracket is the
recommended value for making the ceramic a bit melted). About this testing roll, the micro structure
is hexagon, with the original Volume: 7.88 BCMs; Depth: 21.15 μm.
BD = 600μm,
SCL = 50
l/cm,
SA = 45°,
A bit melted
of the top
wall
Test No. ES (cm/s) DC (%) PL (μs)
Volume
(BCMs)
Depth (μm)
100 45 9 - 14 (12) 75.4 7.85 21.20
101 80 15 - 20 (18) 63.6 7.75 20.81
102 115 21 - 26 (24) 59 7.90 20.87
103 150 29 - 34 (32) 60.3 7.77 20.84
104 185 35 - 40 (38) 58.1 7.82 20.87
Table 4.1 The range of DC in order to melt the surface a bit corresponding to each ES
An example, test 99 (see pdf), was made to illustrate how “a bit meted” would be like. See Figure 4.4.
99: ES = 150 cm/s, SA = 45°, SCL = 50, BD = 600 μm, DC = 32.
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Figure 4.4 Micro images of test 99 before and after post-melting
As can be seen in Figure 4.4, before post-melting, the call wall is thin and sharp. After the melting, the
wall is a bit melted and the thickness increases, which may improve the properties of the cell structure.
Meanwhile, from Table 4.1 it can be seen that the volume and depth nearly not change, which means if
the post-melting is processed right after the engraving, the operators could make the volume just the
same as the customers ask, instead of making it 1-3 BCMs larger.
In addition, as table 4.1 shows, with fixed other parameters, the ES and DC have corresponding linear
relationship to melt the surface a bit, which can be also illustrated by the almost fixed pulse length (PL) –
around 60 μm. By knowing this, operators could test out the proper DC under different ES with higher
speed and accuracy, like Figure 4.5 shows.
Figure 4.5 Relationship between ES and DC when slightly melting the ceramic surface
4.5 Conclusion and prospects
A new production process concept was proposed. After engraving, instead of moving the roll to
finishing process, including liquid washing and polishing, the roll would be kept at the same lathe and
accept a post-melting process. The purpose of the post-melting is to blast the dust away and also try to
make a smoother surface and thicker wall with better structure properties.
See Table 4.2, corresponding to one ES, there is a range of DC provided for the operators to adjust in
case of practical situations (the DC value in the bracket is the recommended value for making the ceramic
a bit melted). With other ES, different DC would be predicted and tested out by using table 4.2 and Figure
4.5.
0
5
10
15
20
25
30
35
40
45
50
0 50 100 150 200 250
DC
(%)
ES (cm/s)
Experiments data
Trend line
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BD = 600μm (Table
2.4),
SCL = 50 l/cm,
SA = 45°,
A bit melted of the
top wall
ES (cm/s) DC (%)
45 9 - 14 (12)
80 15 - 20 (18)
115 21 - 26 (24)
150 29 - 34 (32)
185 35 - 40 (38)
Table 4.2 The range of DC in order to melt the surface a bit corresponding to each ES
All of the sets of the parameters shown in Table 4.2 could blast the dust away and make the cells a bit
melted, which can make a smoother surface and thicker wall with better structure properties. When
operators engrave the rolls, they can make the volume just the same as the customers ask. Because after
the post-melting, the volume and depth would nearly not change.
In addition, one of the functions of the post-melting is to eliminate the optical defects produced
during the engraving. One set of parameters, as stated in Chapter 3.2 (Test 62, 63, 64), is now usually used
for post-melting if optical defects were found after engraving. With the new parameters, for example
Test 103 and 104, the melting effects would be expected to be similar while the processing time could
be half and even more less.
Chapter 5 Roughness changes after laser treatment
The device used to measure the roughness of the anilox rolls is the “Perthometer M2” produced by
Mahr. The device is shown below in Figure 5.1.
Figure 5.1 The sketch of the measurement device - Perthometer M2
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The plan is to use different kinds of laser beams to process the unengraved ceramic surface, and
compare the different roughness changes. Figure 5.2 shows the practical measurement on the anilox
roll.
Figure 5.2 The practical measurement on the anilox roll
The measurement process is to put the detector stable and horizontal on the roll, set the “auto”
mode, press “start” button. The measuring distance is 5.6 mm, therefore the laser processed area
should be longer than 5.6mm. Because of the random error of the measurement device and the
random roughness on the roll, the measurement way is to measure three different places on each
laser treated area, and then calculate the average value.
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First of all, the original smooth surface was tested, data was shown in Table 5.1 below.
a b c average
Original
smooth
surface
Ra (um) 0.263 0.282 0.272 0.272
Rz (um) 2.970 3.060 3.020 3.017
Rmax (um) 3.870 3.960 4.780 4.203
Rk (um) 0.460 0.440 0.470 0.457
Table 5.1 Roughness data of the original unengraved surface of a anilox roll
In the table, a, b, c means the number of times that the detector measures. Roughness average
Ra is the arithmetic average of the absolute values of the roughness profile ordinates.
Figure 5.3 Explanation for Ra
Single roughness depth Rzi is the vertical distance between the highest peak and the deepest
valley within a sampling length. Mean roughness depth Rz is the arithmetic mean value of the single
roughness depths Rzi of consecutive sampling lengths:
Maximum roughness depth Rmax is the largest single roughness depth within the evaluation length.
Figure 5.3 Explanation for Rz and Rmax
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Core roughness depth Rk is the depth of the roughness core profile.
Figure 5.3 Explanation for Rk
All of these four parameters have different evaluating functions for the roughness measurement.
For the laser treatment, different beam diameter and SCL were settled, in order to analyze the
roughness change effects of the different beam properties. An final data sheet is shown in Table 5.2
(For all the three times roughness data, see excel file ”Roughness test”.).
Test
No.
BD
(um)
SCL Ratio DC PF
(kHz)
PL
(us)
Ra
(um)
Rz
(um)
Rmax
(um)
Rk
(um)
1 100 100 2 4.2 10.606 4 0.317 3.360 4.317 0.607
2 100 200 1 8.5 21.214 4 0.337 3.730 4.473 0.687
3 100 300 0.667 8 31.819 2.5 0.352 4.237 6.240 0.653
4 100 400 0.5 8 42.426 1.9 0.337 3.883 4.910 0.593
5 300 33.33 2 9 3.536 25.5 0.297 3.553 4.907 0.530
6 300 66.67 1 15 7.07 21.2 0.316 4.06 5.787 0.543
7 300 100 0.667 18 10.606 17 0.313 4.037 5.053 0.637
8 300 133.33 0.5 19 14.142 13.4 0.31 3.89 5.080 0.660
9 500 20 2 Showing optical spots, not suitable
10 500 40 1 20 4.243 47.1 0.298 3.413 4.263 0.560
11 500 60 0.667 23 6.364 36.2 0.312 3.763 5.823 0.617
12 500 80 0.5 26 8.485 30.7 0.273 3.58 4.680 0.537
13 500 100 0.4 28 10.606 26.4 0.293 3.513 4.583 0.573
14 500 80 0.5 34 8.485 40.1 0.33 3.933 5.410 0.737
15 500 80 0.5 42 8.485 49.5 0.381 4.517 6.847 0.913
Table 5.2 Roughness data of laser treated surface of an anilox roll
In the Table 5.2, the “Ratio” means the ratio between screen line distance and the laser beam
radius on the anilox roll surface. Beam speed is 150 cm/s, SA was chosen to be 45°. The DC was
chosen by the similar principle as in the laser cleaning project, is to choose the critical value of DC
that would just not damage the ceramic. For each roughness parameter, a graph was made to show
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the comparison among different sets of BD and SCL.
5.1 Laser treatment effects on Ra
Figure 5.4 Value of Ra in tests from Table 5.2
As we can see from Table 5.2, test 1-4 BD = 100μm, test 5-8 BD = 300μm, test 10-13 BD = 500μm.
And in each group, SCL increases by each test.
From Table 5.1, Ra of the original surface is 0.272μm. By analyzing Figure 5.4, it could be seen
that after laser treatment, most of the Ra is above 0.3μm, which means laser treatment could
increase the Ra.
With the increase of BD, we can see a small decrease trend of Ra. This means the lower the laser
beam power intensity, the smaller possibility that it would influence the roughness.
And with the increase of SCL (overlap of the beam spots), i.e. the decrease of the ratio between
screen line distance and the laser beam radius, there is no obvious changes on Ra.
5.2 Laser treatment effects on Rz
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
1 2 3 4 5 6 7 8 10 11 12 13
Ra
(um)
Test No.
Value of Ra
1
2
3
4
5
6
7
8
10
11
12
13
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Figure 5.5 Value of Rz in tests from Table 5.2
From Table 5.1, Ra of the original surface is 3.017μm. By analyzing Figure 5.5, it could be seen
that after laser treatment, most of the Rz is above 3.5μm, which means laser treatment could
increase the Rz.
With the increase of BD, we can see a small decrease trend of Ra. This means the lower the laser
beam power intensity, the smaller possibility that it would influence the roughness.
And with the increase of SCL (overlap of the beam spots), i.e. the decrease of the ratio between
screen line distance and the laser beam radius, there is no obvious changes on Ra.
5.3 Laser treatment effects on Rmax
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
1 2 3 4 5 6 7 8 10 11 12 13
Rz
(um)
Test No.
Value of Rz
1
2
3
4
5
6
7
8
10
11
12
13
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Figure 5.6 Value of Rmax in tests from Table 5.2
From Table 5.1, Ra of the original surface is 4.203μm. By analyzing Figure 5.6, it could be seen
that after laser treatment, most of the Rmax is above 4.2μm, which means laser treatment could
increase the Rz.
With the increase of BD, we can see a small decrease trend of Ra. This means the lower the laser
beam power intensity, the smaller possibility that it would influence the roughness.
And with the increase of SCL (overlap of the beam spots), i.e. the decrease of the ratio between
screen line distance and the laser beam radius, there is no obvious regulation to follow on the
change of Rmax. Although relatively test 3, 6 and 11 shows apparent larger Rmax, but because of the
limited data and the random error, this result could be regarded as the measurement errors.
5.4 Laser treatment effects on Rk
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
1 2 3 4 5 6 7 8 10 11 12 13
Rmax
(um)
Test No.
value of Rmax
1
2
3
4
5
6
7
8
10
11
12
13
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Figure 5.7 Value of Rk in tests from Table 5.2
From Table 5.1, Ra of the original surface is 0.457μm. By analyzing Figure 5.7, it could be seen
that after laser treatment, most of the Rmax is above 4.2μm, which means laser treatment could
increase the Rz.
With the increase of BD, we can see a small decrease trend of Ra. This means the lower the laser
beam power intensity, the smaller possibility that it would influence the roughness.
And with the increase of SCL (overlap of the beam spots), i.e. the decrease of the ratio between
screen line distance and the laser beam radius, there is no obvious regulation to follow on the
change of Rmax.
5.5 The effect of DC on the roughness change by laser treatment
In this case, it is known that the melting of the surface could be a big factor for the roughness
changing. So a set of comparison tests were made, with the same BD, SCL, SA, ES, different increasing
DC, i.e. different melting level, to investigate the roughness change. A data sheet was made as Table
5.3.
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
1 2 3 4 5 6 7 8 10 11 12 13
Rk
(um)
Test No.
Value of Rk
1
2
3
4
5
6
7
8
10
11
12
13
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Test
No.
BD
(um)
SCL Ratio DC PF
(kHz)
PL
(us)
Ra
(um)
Rz
(um)
Rmax
(um)
Rk
(um)
Original surface 0.272 3.017 4.203 0.457
12 500 80 0.5 26 8.485 30.7 0.273 3.58 4.680 0.537
14 500 80 0.5 34 8.485 40.1 0.33 3.933 5.410 0.737
15 500 80 0.5 42 8.485 49.5 0.381 4.517 6.847 0.913
Table 5.3 Roughness change with the change of DC (surface melting level)
In Table 5.3, the surface in test 12 nearly not melted, the surface in test 14 melted a bit, and the
surface in test 15 had an obvious melting appearance. As shown, with the increase of DC, all the
parameters representing the roughness: Ra, Rz, Rmax and Rk, their values increase also. This means
that the roughness of surface would increase with the melting level.
5.6 Conclusion for the roughness changes after laser treatment
From Table 5.2 and all the comparison figures in chapter 5, it could be seen that after laser
treatment, most of the Ra, Rz, Rmax and Rk are obviously above their original values, which means
laser treatment could increase the roughness.
With the increase of BD, we can see a small decrease trend of roughness values. This means the
lower the laser beam power intensity, the smaller possibility that it would influence the roughness.
And with the increase of SCL (overlap of the beam spots), i.e. the decrease of the ratio between
screen line distance and the laser beam radius, there is no obvious regulation to follow on the
change of the roughness. Although relatively some tests showed apparent larger roughness values,
because of the limited data and the random error, this result could be regarded as the measurement
errors.
At last, with the increase of DC, all the parameters representing the roughness: Ra, Rz, Rmax and
Rk, their values increase also. This means that the roughness of surface would increase with the
melting level.
To get the relation between the surface tension (wettability) of the surface after laser treatment,
from literature review, it could be known that for not too rough surfaces (roughness significantly
below the wavelength of laser light) we can describe the effect of surface roughness by the so-called
Wenzel equation. The equation predicts that if a molecularly hydrophobic surface is rough, the
appearance is that of an even more hydrophobic surface. If a hydrophilic surface is roughened it
becomes more hydrophilic. [13]
For further investigation, a series of tests could be done on the laser treated area shown in Table
5.2, from which we could know the relation between the roughness and the surface tension
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(wettability), together with the laser treatment parameters.
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References
[1] International Paper - Knowledge center - Flexography:
http://wayback.archive.org/web/20100816235813/http://glossary.ippaper.com/default.asp?req=
knowledge/article/151.
[2] Johansson, Lundberg & Ryberg (2003) "A guide to graphic print production", John Wiley &
Sons Inc., Hoboken, New Jersey.
[3] http://www.apex-groupofcompanies.com/conventional-ceramic-coated-laser-engraved-
anilox-rolls/
[4] http://www.harperimage.com/AniloxRolls/Anilox-Guides/Anilox-Line-Screen
[5] www.praxair.com/printing
[6] V. Veiko, A. Samohvalov, E. Ageev. Laser cleaning of engraved rolls coupled with spectroscopic
control. Optics & Laser Technology 54 (2013) 170–175.
[7] http://www.utwente.nl/ctw/wa/research/laser/
[8] M. Julkarnain, J. Hossain, K. Sharif,.A. Khan, Journal of Optoelectronics and Advanced
Materials, 13,42 (2011) 485–490.
[9] https://en.wikipedia.org/wiki/Chromium%28III%29_oxide
[10] http://www.terolabservices.com/thermal_spraying/technical_papers.asp.
[11] Ziad Tariq Khodair, Gailan Asad Kazem, Ammar Ayesh Habeeb. Studying the optical
properties of ( Cr2O3:I ) thin films prepared by spray pyrolysis technique. Iraqi Journal of Physics,
2012, Vol. 10, No.17, PP. 83-89.
[12] http://support.epiloglaser.com/article_p.aspx?cid=8205&aid=42827
[13] David Quere. Rough ideas on wetting. Physica A 313 (2002) 32–46.
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