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  • 1. Additive Manufacturing Reshaping Manufacturing: Understanding 3D Printing Processes Prof. Brent Stucker Founder & CEO, 3DSIM, LLC Edward R. Clark Chair of Computer Aided Engineering Department of Industrial Engineering, University of Louisville Inaugural Chairman, ASTM F42 Committee on Additive Manufacturing
  • 2. Additive Manufacturing AM has the potential to enable anyone to make many things they require, anywhere!
  • 3. Additive Manufacturing AM enables… …an advanced manufacturing facility to be set up using only electricity, some raw materials, and a computer.
  • 4. Additive Manufacturing AM enables… …an entrepreneur to start selling a new product without ever needing to buy a machine, purchase a tool or prove out a mold; and start shipping products the day after the design is finalized.
  • 5. Additive Manufacturing AM is used for the… …automated manufacture of hearing aids so that you simply scan the ear, print out a custom-fitted hearing aid, insert electronics, and ship them by the millions.
  • 6. Additive Manufacturing What is Additive Manufacturing? (3D Printing) • The process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies
  • 7. Additive Manufacturing University of Louisville’s Involvement in AM • One of the best equipped additive manufacturing (AM) facilities in the world • Performing Basic and Applied Research, since starting with SLS in 1993 • Over 20 people focused on AM • Close partner of leading AM users – Boeing, GE, DoD, service bureaus, etc. • Over 70 member organizations in our RP Center – Includes Haas Technical Education Center
  • 8. Additive Manufacturing Typical AM Process Chain 1. Create CAD Solid Model 2. Generate STL File 3. Verify File & Repair 4. Create Build File 1. Orientation, Location 2. Slicing 3. Support Material Generation 5. Build part layer-by- layer 6. Post-processing Click for Movie
  • 9. Additive Manufacturing What is an STL Model File? • Represents 3D solid models using groups of planar triangles – Describe each triangle by • 3 vertices & unit normal vector – No topological information • Enumerate all triangles • No special order – Better accuracy = smaller triangles = larger files • Set triangle accuracy relative to accuracy of machine used • Holes between triangles, overlapping triangles, and inverted vectors can be problems • No knowledge of dimensions (mm or inches) Facet 1 Facet 2 Facet 3
  • 10. Additive Manufacturing New Additive Manufacturing File Format • AMF – Additive Manufacturing Format – Additive Manufacturing File
  • 11. Additive Manufacturing General Concept (XML) • Parts (objects) defined by volumes and materials – Volumes defined by triangular mesh – Materials defined by properties/names • Color properties can be specified – Color – Texture mapping • Materials can be combined – Graded materials – Lattice/Mesostructure • Objects can be combined into constellations – Repeated instances, packing, orientation
  • 12. <?xml version="1.0" encoding="UTF-8"?> <amf units="mm"> <object id="0"> <mesh> <vertices> <vertex> <coordinates> <x>0</x> <y>1.32</y> <z>3.715</z> </coordinates> </vertex> <vertex> <coordinates> <x>0</x> <y>1.269</y> <z>2.45354</z> </coordinates> </vertex> ... </vertices> <region> <triangle> <v1>0</v1> <v2>1</v2> <v3>3</v3> </triangle> <triangle> <v1>1</v1> <v2>0</v2> <v3>4</v3> </triangle> ... </region> </mesh> </object> </amf> Basic AMF Structure Addresses vertex duplication, leaks of STL & UNITS
  • 13. Additive Manufacturing Compressibility Comparison for 32‐bit Floats; need to look at double precision
  • 14. CURVED PATCH (Curved using vertex normals) PLANNAR PATCH Optionally add normal/tangent vectors  to some triangle mesh vertices  to allow for more accurate geometry.  CURVED PATCH (or curved using edge tangents) Curved patches
  • 15. Additive Manufacturing Multiple Materials Micro- structureGradient Materials
  • 16. Additive Manufacturing Print Constellation • Print orientation • Duplicated objects • Sets of different objects • Efficient packing • Hierarchical
  • 17. Additive Manufacturing Metadata <metadata type=“Author”>John Doe”></metadata> <metadata type=“Software”>SolidX 2.3”></metadata> <metadata type=“Name”>Product 1></metadata> <metadata type=“Revision”>12A”></metadata> <object id=“1”> <metadata type=“Name”>Part A ></metadata> </object id=“1”>
  • 18. Additive Manufacturing How do we build parts using AM? • 7 Process Categories – ASTM/ISO Standard terminology, categories & definitions will be used • What are the secret limitations you might not be aware of? • What types of materials can you use? • What is each process good for?
  • 19. Additive Manufacturing Vat Photopolymerization • An additive manufacturing process in which liquid photopolymer in a vat is selectively cured by light- activated polymerization. – Stereolithography – Envisiontec DLP – Micro-SLA – 2-photon lithography – …
  • 20. Additive Manufacturing Projection Systems • Use a projector (LED or DLP) to illuminate the cross-section – Resolution limited by pixels of projector – Typically faster per layer – Common for micro- stereolithography
  • 21. Additive Manufacturing Envisiontec Perfactory
  • 22. Additive Manufacturing Developments in Vat Photopolymerization • Increased proliferation of DLP/LCD/LED technology to cure entire layers at once. • New photopolymer materials which mimic engineering photopolymers • Expiration of initial stereolithography patents are opening up the marketplace • Renewed interest in 2-photon polymerization for nano-scale components
  • 23. Additive Manufacturing Secrets of Vat Photopolymerization • Always need supports – Thus, we must remove them – Downward facing surfaces are inferior • Photopolymers do not have long-term stability in the presence of light – They continue to react and degrade over time.
  • 24. Additive Manufacturing Materials in VP • Over 20 years of photopolymer research, including by major chemical companies, has led to many resins which you can buy • No materials are “standard engineering-grade” polymers – Specially-formulated to mimic engineering polymers
  • 25. Additive Manufacturing What is VP best for? • High accuracy parts that don’t have stringent structural requirements • Patterns – Investment casting – RTV molding – …
  • 26. Additive Manufacturing Material Jetting • An additive manufacturing process in which droplets of build material are selectively deposited – Wax or Photopolymers – Multiple nozzles – Single nozzles – Includes • Objet • 3D Systems Projet • Stratasys Solidscape machines • Several Direct Write machines • Etc…
  • 27. Additive Manufacturing Single-Droplet • Solidscape Modelmakers – 0.0005” layers – small, accurate parts made slowly
  • 28. Additive Manufacturing Multi-Droplet • Thermojet and Actua from 3D Systems – Prints waxy-like materials • No longer in production, but still serviced
  • 29. Additive Manufacturing Developments in Material Jetting • New Stratasys/Objet Connex 500 – Multi-material & Multi-color • Many traditional “2D printing” companies are investigating 3D printing – Thermoplastics are difficult • Viscosity issues – Metals are starting to be publically discussed • Significant interest in printed electronics – Major industry interest at the intersection between 2½D & 3D geometries
  • 30. Additive Manufacturing Secrets of Material Jetting • Always need supports – Thus, we must remove them – Downward facing surfaces are inferior (particularly true if secondary support materials are not used) • Secondary support materials make support removal easier – Water Soluble – Different Strength – Different Melting Temp
  • 31. Additive Manufacturing Material Jetting Materials • Only commercial materials are wax-like materials or photopolymers – Need low viscosity – Waxes melt at low temperature, but solidify quickly – Photopolymers are cured using light just after deposition • No materials are “standard engineering-grade” polymers – Specially-formulated to mimic engineering polymers
  • 32. Additive Manufacturing What is Material Jetting best for? • Smooth, accurate parts that don’t have stringent structural requirements • Mixing of stiff and flexible materials/colors gives tremendous variability in design – Artwork – Full-color mock-ups – Gradient material assemblies – …
  • 33. Additive Manufacturing Binder Jetting • An additive manufacturing process in which a liquid bonding agent is selectively deposited to join powder materials. – Zcorp – Voxeljet – ProMetal/ExOne – …
  • 34. Additive Manufacturing Developments in Binder Jetting • 3D Systems purchased Zcorp and has changed marketing to “Colorjet” – Printing sugary food and ceramics (pottery & art) – Announced a color personal 3D printer • ExOne is pushing “sand printing” and builds metal parts for Shapeways • Voxeljet, fcubic, etc. make marketplace dynamic – Continuous build platform design has major ramifications
  • 35. Additive Manufacturing Secrets of Binder Jetting • Parts from starch/plaster look pretty but are quite brittle – Post-process infiltration of these materials by cyanoacrylate or another material is needed for strength • Infiltration makes these parts very heavy • Metal parts are not engineering-grade – Mostly applicable to art – Need infiltrated (highest accuracy) or sintered (shrinks)
  • 36. Additive Manufacturing Binder Jetting Materials • Majority of the build material is the powder – Makes the process very, very fast • Materials are by nature “composite” • Gradients in color/properties possible by printing different binders • Any powder which can be spread and then glued, reacted, catalyzed, or otherwise fused using a binder is a candidate • Living tissue and dental ceramics are promising
  • 37. Additive Manufacturing What is Binder Jetting best for? • Color parts used for marketing or proof-of- concept. • Metal parts for artistic purposes or with limited engineering functionality. • Powder metal green parts • Sand casting molds
  • 38. Additive Manufacturing Material Extrusion • An additive manufacturing process in which material is selectively dispensed through a nozzle or orifice – Based on Stratasys FDM machines – Office friendly – DIY community – Best selling platform – …
  • 39. Additive Manufacturing Developments in Material Extrusion • Expiration of initial FDM patents has led to a vast proliferation of personal 3D printers – More “personal” machines sold @$1k-$2k than “industrial” machines for $10k-$200k – Lots of new materials, competitors, etc. – Many ways for consumers to access & buy these machines • 3D Systems & Stratasys offer personal 3D printers in addition to their industrial offerings • Renewed interest in “manufacturing” parts via extrusion – High-temp materials, concrete, fiber-reinforced composites, etc. – People seem to be taking it more seriously than a few years ago
  • 40. Additive Manufacturing Secrets of Material Extrusion • Always need supports – Thus, we must remove them – Downward facing surfaces are inferior • Secondary support materials make support removal easier – Water soluble, easier to remove, etc. • Fundamental tradeoffs in build style mean you can NEVER be fully dense & simultaneously achieve maximum accuracy without post-processing
  • 41. Additive Manufacturing Material Extrusion Materials • Commercial materials include easy to extrude engineering polymers – ABS, PC, PC/ABS, PPSF, etc. – Chocolate and meltable food products – Many DIY materials being explored • Syringe & pumped nozzles also available – Pastes, glue, cement – Frosting & other food products • Need materials which soften under shear load and maintain their shape after deposition
  • 42. Additive Manufacturing What is Material Extrusion best for? • Inexpensive prototypes • Functional parts without stringent engineering constraints – Limited fatigue strength • Great platform on which to try lots of things – Living tissue – Food – Toys
  • 43. Additive Manufacturing Powder Bed Fusion • An additive manufacturing process in which thermal energy selectively fuses regions of a powder bed – SLS, SLM, DMLS, EBM, BluePrinter, etc. – Polymers, metals & ceramics
  • 44. CO2 Laser X-Y Scanning Mirrors Feed Cartridges Part Cylinder Counter-Rotating Powder Leveling Roller Laser Beam Selectively Melts Powder SELECTIVE LASER SINTERING
  • 45. 45 Loose Powder
  • 46. 46 Energy is Applied – Laser or Electron Beam Energy Radiation/ Heat from Energy Source
  • 47. 47 The Powder Begins to Heat Due to Incident Radiation
  • 48. 48 The Outside of the Particles Heat More Quickly than the Inside
  • 49. 49 Smaller Particles Begin to Melt
  • 50. 50 Larger Particles May or May Not Melt Depending Upon Dwell Time of Radiation
  • 51. 51 Melted Portions of the Material Begin to Coalesce (Sinter) Resulting in a Physical Bond and Shrinkage
  • 52. 52 When the Heat is Removed, the Part Cools as a Porous Solid
  • 53. 53 Melting within a Powder Bed Can Lead to Curl
  • 54. 54 Melting within a Powder Bed Can Lead to Curl
  • 55. 55 Melting within a Powder Bed Can Lead to Curl
  • 56. 56 Melting within a Powder Bed Can Lead to Curl
  • 57. 57 Undesirable Shrinkage Controllable Shrinkage Heater Scanning System Comparison of Shrinkage With and Without Heaters
  • 58. 58 Undesirable Shrinkage Controllable Shrinkage Scanning SystemHeaterHeater Comparison of Shrinkage With and Without Heaters
  • 59. 59 Undesirable Shrinkage Controllable Shrinkage Scanning SystemHeater Index Comparison of Shrinkage With and Without Heaters
  • 60. 60 Undesirable Shrinkage Controllable Shrinkage Scanning SystemHeater Comparison of Shrinkage With and Without Heaters
  • 61. Additive Manufacturing Metal Laser Sintering Methods for Controlling Shrinkage Complex Scan Patterns Supports
  • 62. Additive Manufacturing Electron Beam Melting (EBM) Arcam • Electrons are emitted from a heated filament >2500° C • Electrons accelerated through the anode to half the speed of light • A magnetic lens focuses the beam • Another magnetic field controls deflection • When the electrons hit the powder, kinetic energy is transformed to heat. • The heat melts the metal powder No moving parts!
  • 63. Additive Manufacturing EBM versus Laser Processes • EBM Benefits – Energy efficiency – High power (4 kW) in a narrow beam – Incredibly fast beam speeds • No galvanometers – Fewer supports • EBM Drawbacks – Only works in a vacuum • Gases (even inert) deflect the beam – Does not work well with polymers or ceramics • Needs electrical conductivity – Needs larger powder particles
  • 64. Additive Manufacturing Developments in Powder Bed Fusion • The most-used platform for “functional parts” • Significant R&D investments • Many metal laser sintering machine manufacturers – SLM Solutions, ConceptLaser, EOS, Phenix, Renishaw, Realizer • Starting to see new polymer machine manufacturers – Several companies entering the marketplace to compete with 3D Systems & EOS • Open versus Closed machine architecture battles • GE’s purchase of Morris Technologies (2012) is still having major ramifications on the metal laser sintering marketplace
  • 65. Additive Manufacturing Secrets of Powder Bed Fusion • An Expert User is the most critical aspect of getting a good part – User-selected trade-offs between speed, accuracy and strength in polymer laser sintering – Takes about a year to learn enough to consistently make good parts in metal processes • Polymers are not 100% recyclable • Metal supports are a huge pain – $50k-$100k/year per machine waste is common • Blade crashes and/or over-supporting
  • 66. Additive Manufacturing Polymer Materials in Powder Bed Fusion • You can use any material you want, as long as it’s nylon – Or if it meets the cooling curve • Opposite of injection molding – Fast heating, slow cooling
  • 67. Additive Manufacturing Metal Materials in Powder Bed Fusion • Most casting and welding alloys can be processed using metal laser sintering – Very fast melting & solidification times gives unique properties & challenges – High reflectivity, high thermal conductivity materials are difficult to process (copper, gold, aluminum, etc.) • Titanium is the “sweet spot” for EBM
  • 68. Additive Manufacturing Other Materials in Powder Bed Fusion • Ceramics are difficult, but possible to directly process • Green parts are easy to process – Powder metallurgy, sand casting, etc.
  • 69. Additive Manufacturing What is Powder Bed Fusion best for? • Manufacturing end-use products – Polymer parts from Nylon 11 or 12 (including glass- filled nylons) – Metal parts from Titanium, Stainless Steel, Inconel super alloys, tool steels and more • Prototyping components where functional testing is required on the prototype
  • 70. Additive Manufacturing Sheet Lamination • An additive manufacturing process in which sheets of material are bonded to form an object. – Paper (LOM) • Using glue – Plastic • Using glue or heat – Metal • Using welding or bolts • Ultrasonic AM…
  • 71. Additive Manufacturing Developments in Sheet Lamination • Renewed interest in paper-based machines at the low-end by Mcor and others • Fabrisonics sells 3 platforms based upon metal ultrasonic additive manufacturing • Other solid state AM methods are being investigated – Friction stir AM, etc.
  • 72. Additive Manufacturing Secrets of Sheet Lamination • Getting rid of excess material is difficult – Cut then Stack – versus – Stack then Cut – Mechanical properties are typically quite poor
  • 73. Additive Manufacturing Materials in Sheet Lamination • Paper is used for proof of concept parts – Color printing on the paper gives color parts • Metal sheets can be cut and stacked for tooling and other applications • Ceramic tapes can be cut and stacked and then fired for ceramic parts • Polymer sheets (such as by Solido) can be bonded and cut to form prototypes
  • 74. Additive Manufacturing What is Sheet Lamination best for? • Paper machines make cheap physical representations of your design • Original LOM-like machines can be used like wood as patterns for sand casting, or as topographical maps, etc. • Metal laminated tooling reduces the time to build large molds such as for stamping • Micro-fluidic ceramic parts can be made using ceramic tapes
  • 75. Additive Manufacturing – Wire & Powder Materials – Lasers & Electron Beams – Great for feature addition & repair Directed Energy Deposition • An additive manufacturing process in which focused thermal energy is used to fuse materials by melting as they are being deposited
  • 76. Additive Manufacturing Developments in Directed Energy Deposition • Electron Beam with wire seems to be leading for part production currently • DoD is interested in laser powder deposition for repair (America Makes project) – Manufacturers are marketing laser deposition heads as add- ons to existing machine tools
  • 77. Additive Manufacturing Secrets of Directed Energy Deposition • Material needs something to land on (supports) – We don’t typically make 3D complex parts, just complex parts with mostly upward-facing features • There is a direct correlation between feature size and build speed. – Accurate processes are painfully slow – Fast process are very inaccurate • Surface finish & accuracy requirements almost always require finish machining
  • 78. Additive Manufacturing Materials in Directed Energy Deposition • Most metal alloys can be deposited with some success – Rapid cooling affects properties • Polymers and ceramics rarely used, but possible Optical Absorption vs Wavelength Wavelength (microns)
  • 79. Additive Manufacturing What is Direct Energy Deposition best used for? • Adding features to existing structures – Replace complex forgings with sheet structures that we build up near-net shape parts on • Repair & refurbishment of existing components – Qualified for many high-performance applications
  • 80. Additive Manufacturing General Comments • Powder Materials • Modeling • Implications of AM
  • 81. Additive Manufacturing Powders • Small powder particles – Give better feature resolution, surface finish, accuracy and layer thicknesses – Are difficult to spread and/or feed – Become airborne easily (repel in EBM) – React with oxygen easily • Spherical powders with a tight PSD are best • Powder morphology, packing density, fines, etc. make a HUGE difference in some processes
  • 82. Additive Manufacturing AM can now enable us to… …control the overall geometry of a part, which could be made up of a truss network, where each truss has an optimized thickness and could have an individually controllable microstructure or material. • But we don’t know how to: • Efficiently represent this type of multi-scale geometry in a CAD environment, or • Efficiently optimize these multi-scale features, or • Efficiently simulate the link between AM process parameters and microstructure, or • Efficiently compute the effects of changes in microstructure on part performance Courtesy David Rosen, Georgia Tech
  • 83. Additive Manufacturing Simulation Needs • We need improved computational design tools for additive manufacturing • Like those used for injection molding and casting/forging • But, physics-based tools are inefficient when applied to AM • Requires dramatic simplification of the process and/or geometry • Instead, AM-industry software focuses primarily on geometry and not process control or performance/quality • Forces the AM industry to continue the Build/Test/ Redesign cycle of traditional manufacturing.
  • 84. Additive Manufacturing • Process simulations that are faster than an AM machine builds a part – Predict residual stress and distortion so we know how to place supports and how to pre-distort our CAD model • Material simulations which can predict crystal level details and the resulting mechanical properties • Lightning fast solutions on GPU-based platforms • We simulate only what we need to get a practical answer as FAST as possible • Come tomorrow morning to hear more….
  • 85. Additive Manufacturing Engineering Implications • More Complex Geometries – Internal Features – Parts Consolidation – Designed internal structures • No Tools, Molds or Dies – Direct production from CAD • Unique materials – Controllable microstructures – Multi-materials and gradients – Embedded electronics
  • 86. Additive Manufacturing Business Implications • Enables business models used for 2D printing, such as for photographs, to be applied in 3D – Print your parts at home, at a local “FedEx Kinkos,” through “Shapeways” or at a local store • Removes the low- cost labor advantage • Entrepreneurship – Patents expiring • New Machines – Software tools – Service providers Pharmaceutical Manufacturing in China
  • 87. Additive Manufacturing Web 2.0 + AM = Factory 2.0 • User-changeable web content plus a network of AM producers is already enabling new entrepreneurial opportunities – – Freedom of Creation – FigurePrints – Spore – …and more 87
  • 88. Additive Manufacturing Impact on Logistics • Eliminates drivers to concentrate production • “Design Anywhere / Manufacture Anywhere” is now possible – Manufacture at the point of need rather than at lowest labor location – Changing “Just-in-Time Delivery” to “Manufactured- on-Location Just-in-Time”
  • 89. Additive Manufacturing Big Picture Possibilities • Additive Manufacturing has the potential to: – Make local manufacturing of products normative • Small businesses can successfully compete with multi-national corporations to produce goods for local consumption • Parts produced closer to home cost the same as those made elsewhere, so minimizing shipping drives regional production – Reverse increasing urbanization of society • No need to move to the “big city” if I can design my product and produce it anywhere – Make jobs resistant to outsourcing • Creativity in design becomes more important than labor costs for companies to be successful 89
  • 90. Additive Manufacturing Questions & Comments? +1-502-852-2509