In the recent decades of development of manufacturing and production engineering, 3D printing technology has emerged as one of the most promising area for research and development. With the availability of flexible and user friendly manufacturing and interfacing system, the 3D printing technology has attracted a lot of researchers form keen aspects of their field.
Medical Engineering is the branch of science that deal with the application of technological aspects in solving medical problems. With the merger in these two vast fields a lot of problems has been answered and the development of new things is on their verge of initiation.
In the recent decade both the engineers and medical researchers have worked on integration of technologies to solve the medical problems globally. In the scenario, a lot of technology like 3D printed Heart, Kidneys, etc., & physical implants like teeth’s, bones and medical support.
In this report, I have tried to acknowledge the work done in the field with their importance in the ever changing scenario of the world.
This presentation is made on the Evolution of Additive Manufacturing. It has a brief description of Additive Manufacturing. It also has a history of Additive Manufacturing, followed by how 3D printing technology was developed and printers were evolved. Also, how it gained media attention and also its application in various fields are covered.
Basic Terminologies:
Tension:
A load that tries to pull parts straight apart
Compression
A load that forces parts straight into one another
Shear
A load that pulls sideways
Cleavage
A load that pulls parts away from each other at an angle
Peel
A load that pulls parts straight away from one another
BUCKLES AND ITS TYPES:
Buckles occur when metal has been bent past it’s elastic limit
Work hardening has occurred and a new shape is formed
The buckles found in indirect damage are as follows:
simple hinge
collapsed hinge
simple rolled
collapsed rolled
Power from the burnt gases in the combustion chamber is delivered to the crankshaft through the piston, piston pin and connecting rod. The crankshaft changes reciprocating motion of the piston in cylinder to the rotary motion of the flywheel. Crankshaft is designed for multi cylinder engine and its 3D model is created using modeling software CATIA V5R20.The 3D printer prints the CATIA design layer by layer forming a real object. 3D printing process is derived from inkjet desktop printers in which multiple deposit jets and the printing material, layer by layer derived from the CATIA data. 3D printing significantly challenges mass production processes in the future. This type of printing is predicted to influence industries, like automotive, medical, education, equipment, consumer products industries and various businesses. T. Venkata Ramana | Sagam Kunta Subhash | Sangem Devendra Kumar | Vanga Balakrishna ""Modelling and 3D Printing of Crankshaft"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23224.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23224/modelling-and-3d-printing-of-crankshaft/t-venkata-ramana
This presentation is made on the Evolution of Additive Manufacturing. It has a brief description of Additive Manufacturing. It also has a history of Additive Manufacturing, followed by how 3D printing technology was developed and printers were evolved. Also, how it gained media attention and also its application in various fields are covered.
Basic Terminologies:
Tension:
A load that tries to pull parts straight apart
Compression
A load that forces parts straight into one another
Shear
A load that pulls sideways
Cleavage
A load that pulls parts away from each other at an angle
Peel
A load that pulls parts straight away from one another
BUCKLES AND ITS TYPES:
Buckles occur when metal has been bent past it’s elastic limit
Work hardening has occurred and a new shape is formed
The buckles found in indirect damage are as follows:
simple hinge
collapsed hinge
simple rolled
collapsed rolled
Power from the burnt gases in the combustion chamber is delivered to the crankshaft through the piston, piston pin and connecting rod. The crankshaft changes reciprocating motion of the piston in cylinder to the rotary motion of the flywheel. Crankshaft is designed for multi cylinder engine and its 3D model is created using modeling software CATIA V5R20.The 3D printer prints the CATIA design layer by layer forming a real object. 3D printing process is derived from inkjet desktop printers in which multiple deposit jets and the printing material, layer by layer derived from the CATIA data. 3D printing significantly challenges mass production processes in the future. This type of printing is predicted to influence industries, like automotive, medical, education, equipment, consumer products industries and various businesses. T. Venkata Ramana | Sagam Kunta Subhash | Sangem Devendra Kumar | Vanga Balakrishna ""Modelling and 3D Printing of Crankshaft"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23224.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23224/modelling-and-3d-printing-of-crankshaft/t-venkata-ramana
Modelling and 3D Printing of Differential Gear Boxijtsrd
The main aim of the project is to focus on the modeling and 3D printing of differential gear box. Differential permit each of the driving wheels to rotate at different speeds, while for most vehicles supplying equal torque to each of them. A vehicles wheels rotate at divergent speeds, mainly when turning corners. The differential is designed to operate a pair of wheels with same torque while permit them to rotate at different speeds. Differential gear box is designed in CATIA V5 software and manufactured using additive manufacturing 3D printing . The function of gear is to protect and provide a platform for gear transmission. It also provides supports for moving parts and protection from outside environmental condition. Yogesh Avula | Vanga Rajeev Narayana Reddy | VojaAnand Swaroop | Varikuppala Srisailam ""Modelling and 3D Printing of Differential Gear Box"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23287.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23287/modelling-and-3d-printing-of-differential-gear-box/yogesh-avula
Abstract 3D Printing is a process of manufacturing the product on the layer by layer. And it is best processes for producing a finished objects. It was started in 1980‟s with the invention of stereo lithography. It has gone through various ups and downs throughout its development and rejection of new technologies. In this paper, we h3ave summarized the printing of hollow compounds with different shapes. Applications of 3D printed hollow compounds are turbine blades, gears, disc brakes etc. One of the major application of 3D printing is hollow turbine blade. A turbine blade is the individual components. These are used to up the turbine section of a gas turbine. The blades must designed to withstand the high pressure and high temperature comings from combustor. These 3D printed hollow compounds has same strength as solid compounds when compared. Major advantages of the Hollow shaped compounds are heat transfer, low material cost. The aim of the paper is to reduce the cost of material and easy manufacturing of hollow compounds compared to traditional process and taken hollow turbine blade as example. Keywords: hollow compounds, 3D printing, turbine blades, Additive manufacturing.
A prosthetic is a device that replaces any missing human body part visibly and functionally. Reverse engineering is a field of engineering wherein a model and further a prototype can be generated by extracting information from previous design or available model using the advanced tools of CAD/CAM. This paper aims at exploring the needs and advantages of connecting the prosthetic industry with reverse engineering in a developing country like India for patients with lower limb amputations under the brimming concept of “Make in India”.
RECENT DEVELOPMENTS AND DESIGN OF TOOLS FOR PUNCHING AND CUTTINGIAEME Publication
Intensive utilization of computers is especially emphasized in the field of industrial
production, where use of computer applications achieves significant savings in regard
to the time required for manufacturing of products. Shortening of the production time
decreases the production costs and new products are faster introduced to the market,
thus making the company more competitive. In addition to the shorter time for
production, better precision and accuracy is also accomplished, resulting with better
product quality at the end.
Due to the fact that, for the reason of cost-effectiveness of manufacturing of tools,
processing of sheet metal on presses is primarily performed in the course of serial
production, this paper focuses on an analysis of the use of computers in the process of
design of tools for punching and cutting of sheet metal on presses. The presented
methodology encompasses all phases in the process of design of tools – from planning
the work piece until the final design of the tool for punching and cutting, with an
emphasis on the activities performed exclusively by computer applications.
The result of this research is a 3D geometrical model of a tool for punching and
cutting, with an explanation of characteristics of its construction parts, calculation of
its executive parts, analysis and simulation of operation of the tool, and finally the
conclusion on the representation and importance of the utilization of computer
applications in the process of design of such tools
Analyze Gear Failures and Identify Defects in Gear System for Vehicles Using ...IOSR Journals
Abstract: Gear defects are a major reason for poor quality and of embarrassment for manufacturers. 0 Inspection processes done on these industries are mostly manual and time consuming. To reduce error on identifying gear defects requires more automotive and accurate inspection process. Considering this lacking, this research implements a Gear Defect Recognizer which uses computer vision methodology with the combination of local thresholding to identify possible defects. The recognizer identifies the gear defects within economical cost and produces less error prone inspection system in real time. In order to generate data set, primarily the recognizer captures digital gear images by image acquisition device and converts the RGB images into binary images by restoration process and local threshold techniques. Later, the outputs of the processed image are the area of the faulty portion and compute the possible defective and non -defective gear as an output. Detection of bad quality plastic gears is critical for any manufacturing unit trying to make a mark in the market in terms of quality standard and cost. Here we explore the possibility of using image segmentation and algorithms like non-smooth surface detection algorithms to automate the process of defect detection. In these plastics we have picked industrial strength plastic gears used typically in applications like robotic arms where quality in paramount for the functioning of the device. In this paper review of various gear defects and the possible automated solutions using image processing techniques for defect detection is given. Keywords: Defect detection, image processing, computer vision, thresholding, counting number of teeth's.
Design and Modelling of a Leaf Spring using 3D Printing Technologyijtsrd
3D printing technology forms the basis of corporation's prototyping process. 3D printing technology creates 3D physical protypes by solidifying layers of deposited power by using a liquid binder. 3D printing is an versatile process accommodating geometry of varying complexity in hundreds of different applications, and supporting many types of materials. By eliminating production steps and using substantially less material, additive process could be able to reduce waste and save more than 50 of energy compared to today's subtractive manufacturing process and reduce material cost upto 90 . The use of additive manufacturing can potentially benefit a wide range of industries including defence, aerospace, automotive, biomedical, consumer products and metal manufacturing. A leaf spring is a simple form of spring, normally used for the suspension in wheeled cars. Leaf springs are long and narrow plates attached to the body of a trailer that rests above or under trailer's axle. For safe and cozy using, to prevent the street shocks from being transmitted to the car components and to guard the guard the occupants from the road shocks it's miles important to determine the maximum safe strain and deflection. The objective is to find the stresses and deformation in the leaf spring via making use of static load on it. One of a kind of special materials with mechanical properties are taken into consideration for the structural static evaluation. All leaf spring has linear characteristics there is a linear dependence between force and deflection this means that the 3D printed springs could be used as machine elements in different applications. B. Shushma | Ch. Pavan | D. Vikas Reddy | G. Venu Madhav | A. Mukhul Vamshi ""Design and Modelling of a Leaf Spring using 3D Printing Technology"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020, URL: https://www.ijtsrd.com/papers/ijtsrd29589.pdf
Paper Url : https://www.ijtsrd.com/engineering/mechanical-engineering/29589/design-and-modelling-of-a-leaf-spring-using-3d-printing-technology/b-shushma
3D printing is a process of making a three -dimensional solid objects from a digital file using additive manufacturing techniques. In this process layers of material are successively deposited one above the other to create an object. Each layer can be visualized like thinly sliced section of the object. The key to this 3D printer is the thermoplastic extruder which is coupled with a Cartesian XYZ platform. 3D printing by using PLA filament electronics are based around the popular Arduino development platform,utilizing a custom made board for interfacing with the Arduino development Board and allowing stepper motor and extrusion temperature monitoring and control. In very simple terms,3D Printer (not to be confused with printers we see in everyday life) is electromechanical device that builds physical object with very high precision(100 micron or .1mm) at a very low cost.
A Textbook on Sanganer's Hand Block Printing by Haridwar and Deepak SharmaHitesh Sharma
Rajasthan is one of the major historical centres of Block Printing in the world. The seeds of traditional woodblock print – i.e. Buti Print and Butta Print were laid here by our ancestors. And as the history could be traced to the Rangrez Community and Chippa Community were the first to industrialized the block printing art.
Also, to be noted that currently, we could find various textile products which are dated back to the 7th century that was crafted using the same traditional printing art. Hence, as one of the oldest art form, Handblock Printing is a true gift from our ancestors to the modern world.
Stereolithography - Presentation By Hitesh SharmaHitesh Sharma
In the recent decades of development of manufacturing and production engineering, 3D printing technology has emerged as one of the most promising area for research and development. With the availability of flexible and user friendly manufacturing and interfacing system, the 3D printing technology has attracted a lot of researchers form keen aspects of their field.
Medical Engineering is the branch of science that deal with the application of technological aspects in solving medical problems. With the merger in these two vast fields a lot of problems has been answered and the development of new things is on their verge of initiation.
In the recent decade both the engineers and medical researchers have worked on integration of technologies to solve the medical problems globally. In the scenario, a lot of technology like 3D printed Heart, Kidneys, etc., & physical implants like teeth’s, bones and medical support.
In this report, I have tried to acknowledge the work done in the field with their importance in the ever changing scenario of the world.
Conversion of Waste Plastic to Fuel by Hitesh SharmaHitesh Sharma
Pyrolysis is a process which involves thermochemical decomposition of organic matter at high temperature (>370◦C) in the absence of oxygen. Products of this process are Pyrolysis Oil, Carbon Black, and Hydrocarbons. This review paper is focusing the most efficient and widely used method of converting plastics to fuels: ‘Pyrolysis’ and its effectiveness on resolving the both issues of waste plastic management and the requirement of a good alternative fuel for use.
Final Year Project Report Sample for Engineers - IIT and State UniversityHitesh Sharma
A sample report for all final year college students, for Engineering and Management Branch.
Best for Mechanical and Core branch students.
Includes - First Page, Index Style, Abstract, Body, COnsclusion and Designing Methods.
Share and Support this file, thanks and also fo for my other uploads.
Design and Fabrication for Motorized Automated Screw JackHitesh Sharma
Final Year Project Presentation including the gantt chart.
-Format
-Introduction
-Objective
-design
-references
Project title- "Design and Fabrication of Motorized automated Object Lifting Jack"
Summer Training Report for National Engineers Limited for the engineers. Rajasthan Technical University Training format. Swami Keshwanand Institute of Technology (SKIT).
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
1. SKIT,Jaipur
| S t e r i o l i t h o g r a p h y a n d i t s a p p l i c a t i o n i n M e d i c a l S c i e n c e
“Stereolithography & its application in Medical Science.”
A
Seminar Report
Submitted in partial fulfillment
For the award of the
Degree of Bachelor of technology
in Department of Mechanical Engineering
(Academic Session 2013-17)
ProjectGuide
Mr. Dheeraj Joshi
(Reader and Dept. Head)
ProjectCoordinators:
Mr. Dinesh Sharma
Mr. Ankit Agarwal
Department of Mechanical Engineering
Swami Keshvanand Institute of Technology, Management & Gramothan.
Submitted By:
Hitesh Sharma
[13ESKME036]
2. i
CERTIFICATE
This is to certify that the Seminar presentation entitled “Steriolithography and its application in
Medical Science” has been submitted to the Department of Mechanical Engineering, Swami
Keshvanand Institute of Technology, Management and Gramothan (Rajasthan Technical
University, Kota) for the fulfillment of the requirement for the award of the degree of Bachelor of
Technology in “Mechanical Engineering” by following student of final year B.Tech. (Mechanical
Engineering).
Student Name (with Roll no.)
Hitesh Sharma (13ESKME036)
Project Guide Head of Department
Mr. Dheeraj Joshi Mr. N.K. Banthiya
3. ii
ACKNOWLEDGMENT
I like to share my sincere gratitude to all those who help us in completion of this report. During
the work I faced many challenges due to my lack of knowledge and experience but these people
help us to get over from all the difficulties and in final compilation of our idea to a shaped
sculpture.
I would like to thank Mr. Dheeraj Joshi sir for his governance and guidance, because of which I
was able to learn the minute aspects of the study.
I would also like to show mine gratitude to our Coordinators Mr. Dinesh Sharma and Mr. Ankit
Agarwal for their continuous help and monitoring during the work.
In the last I would like to thank the management of Swami Keshvanand Institute of Technology,
Management and Gramothan for providing me such an opportunity to learn from these
experiences.
I am also thankful to Mr. Narendra K. Banthiya Sir, Mr. Alok Mathur Sir and all the Faculties and
Staff of Department of Mechanical Engineering, SKIT, for their help and support towards this
study.
I am also thankful to my class and most of all to my parents who have inspired me to face all the
challenges and win all the hurdles in my life.
Thank you All.
4. iii
ABSTRACT
In the recent decades of development of manufacturing and production engineering, 3D printing
technology has emerged as one of the most promising area for research and development. With
the availability of flexible and user friendly manufacturing and interfacing system, the 3D printing
technology has attracted a lot of researchers form keen aspects of their field.
Medical Engineering is the branch of science that deal with the application of technological aspects
in solving medical problems. With the merger in these two vast fields a lot of problems has been
answered and the development of new things is on their verge of initiation.
In the recent decade both the engineers and medical researchers have worked on integration of
technologies to solve the medical problems globally. In the scenario, a lot of technology like 3D
printed Heart, Kidneys, etc., & physical implants like teeth’s, bones and medical support.
In this report, I have tried to acknowledge the work done in the field with their importance in the
ever changing scenario of the world.
6. v
Figure 1Typical process chain of various Rapid Prototyping systems .....................................................2
Figure 2 Generalized illustration of data flow in Rapid Prototyping.......................................................3
Figure 3. Classification of Rapid Prototyping Processes........................................................................4
Figure 4 Fine point structure for Stereolithography ...............................................................................5
Figure 5. Selective Laser Sintering System...........................................................................................6
Figure 6. Fused Deposition Modeling Process ......................................................................................7
Figure 7. Laminated Object Manufacturing Process..............................................................................8
Figure 8. Steriolithography Manufacturing Setup................................................................................10
7. vi
Table 1. Historical Development of Rapid Prototyping Technology .......................................................1
8. SKIT,Jaipur
1 | S t e r i o l i t h o g r a p h y a n d i t s a p p l i c a t i o n i n M e d i c a l S c i e n c e
Chapter 1: Introduction
1.1. Prototyping
Prototyping or model making is one of the important steps to finalize a product design. It helps in
conceptualization of a design. Before the start of full production a prototype is usually fabricated
and tested. Manual prototyping by a skilled craftsman has been an age-old practice for many
centuries. Second phase of prototyping started around mid-1970s, when a soft prototype modeled
by 3D curves and surfaces could be stressed in virtual environment, simulated and tested with
exact material and other properties. Third and the latest trend of prototyping, i.e., Rapid
Prototyping (RP) by layer-by-layer material deposition, started during early 1980s with the
enormous growth in Computer Aided Design and Manufacturing (CAD/CAM) technologies when
almost unambiguous solid models with knitted information of edges and surfaces could define a
product and also manufacture it by CNC machining. The historical development of Rapid
Prototyping and related technologies is presented in table 1.
Table 1. Historical Development of Rapid Prototyping Technology
Year of Inception Technology
1770 Mechanization
1946 First Computer
1952 First NC Machine Tool
1960 First Commercial LASER
1961 First Commercial Robot
1963 First Version of CAD (Early Version)
1988 First Rapid Prototyping Machine
9. 2
1.2. Basic principle of rapid prototyping processes
The process belong to the generative (or additive) production processes unlike subtractive or
forming processes such as lathing, milling, grinding or coining etc. in which form is shaped by
material removal or plastic deformation. In all commercial rapid prototyping processes, the part
is fabricated by deposition of layers contoured in a (x-y) plane two dimensionally. The third
dimension (z) results from single layers being stacked up on top of each other, but not as a
continuous z-coordinate. Therefore, the prototypes are very exact on the x-y plane but have stair-
stepping effect in z-direction. If model is deposited with very fine layers, i.e., smaller z-stepping,
model looks like original. Rapid prototyping can be classified into two fundamental process steps
namely generation of mathematical layer information and generation of physical layer model.
Typical process chain of various rapid prototyping systems is shown in figure 1.
Figure 1. Typical process chain of various Rapid Prototyping systems
It can be seen from figure 1 that process starts with 3D modeling of the product and then STL file
is exported by tessellating the geometric 3D model. In tessellation various surfaces of a CAD
model are piecewise approximated by a series of triangles (figure 2) and co-ordinate of vertices of
triangles and their surface normal are listed. The number and size of triangles are decided by facet
deviation or chordal error as shown in figure 2. These STL files are checked for defects like flip
10. 3
triangles, missing facets, overlapping facets, dangling edges or faces etc. and are repaired if found
faulty. Defect free STL files are used as an input to various slicing software. At this stage choice
of part deposition orientation is the most important factor as part building time, surface quality,
amount of support structures, cost etc. are influenced. Once part deposition orientation is decided
and slice thickness is selected, tessellated model is sliced and the generated data in standard data
formats like SLC (stereolithography contour) or CLI (common layer interface) is stored. This
information is used to move to step 2, i.e., generation of physical model. The software that operates
rapid prototyping systems generates laser-scanning paths (in processes like Stereolithography,
Selective Laser Sintering etc.) or material deposition paths (in processes like Fused Deposition
Modeling). This step is different for different processes and depends on the basic deposition
principle used in rapid prototyping machine. Information computed here is used to deposit the part
layer-by-layer on rapid prototyping system platform. The generalized data flow in rapid
prototyping is given in figure 2.
Figure 2 Generalized illustration of data flow in Rapid Prototyping
11. 4
1.3.Rapid prototyping processes
The professional literature in rapid prototyping contains different ways of classifying rapid
prototyping processes. However, one representation based on German standard of production
processes classifies rapid prototyping processes according to state of aggregation of their original
material and is given in figure 3.
Figure 3. Classification of Rapid Prototyping Processes
1.3.1. Stereolithography
In this process photosensitive liquid resin which forms a solid polymer when exposed to ultraviolet
light is used as a fundamental concept. Due to the absorption and scattering of beam, the reaction
only takes place near the surface and voxels of solid polymeric resin are formed. A SL machine
consists of a build platform (substrate), which is mounted in a vat of resin and a UV Helium-
Cadmium or Argon ion laser. The laser scans the first layer and platform is then lowered equal to
one slice thickness and left for short time (dip-delay) so that liquid polymer settles to a flat and
12. 5
even surface and inhibit bubble formation. The new slice is then scanned. In new SL systems, a
blade spreads resin on the part as the blade traverses the vat. This ensures smoother surface and
reduced recoating time. It also reduces trapped volumes which are sometimes formed due to
excessive polymerization at the ends of the slices and an island of liquid resin having thickness
more than slice thickness is formed. Once the complete part is deposited, it is removed from the
vat and then excess resin is drained. It may take long time due to high viscosity of liquid resin.
The green part is then post-cured in an UV oven after removing support structures.
Overhangs or cantilever walls need support structures as a green layer has relatively low stability
and strength. These overhangs etc. are supported if they exceed a certain size or angle, i.e., build
orientation. The main functions of these structures are to support projecting parts and also to pull
other parts down which due to shrinkage tends to curl up (Gebhardt, 2003). These support
structures are generated during data processing and due to these data grows heavily specially with
STL files, as cuboid shaped support element need information about at least twelve triangles. A
solid support is very difficult to remove later and may damage the model. Therefore a new support
structure called fine point was developed by 3D Systems (figure 6) and is companys trademark.
Build strategies have been developed to increase build speed and to decrease amount of resin by
depositing the parts with a higher proportion of hollow volume. These strategies are devised as
these models are used for making cavities for precision castings. Here walls are designed hollow
connected by rod-type bridging elements and skin is introduced that close the model at the top and
the bottom. These models require openings to drain out uncured resin.
Figure 4 Fine point structure for Stereolithography
13. 6
1.3.2. Selective Laser Sintering
In Selective Laser Sintering (SLS) process, fine polymeric powder like polystyrene, polycarbonate
or polyamide etc. (20 to 100 micrometer diameter) is spread on the substrate using a roller. Before
starting CO2 laser scanning for sintering of a slice the temperature of the entire bed is raised just
below its melting point by infrared heating in order to minimize thermal distortion (curling) and
facilitate fusion to the previous layer. The laser is modulated in such away that only those grains,
which are in direct contact with the beam, are affected. Once laser scanning cures a slice, bed is
lowered and powder feed chamber is raised so that a covering of powder can be spread evenly over
the build area by counter rotating roller. In this process support structures are not required as the
unsintered powder remains at the places of support structure. It is cleaned away and can be recycled
once the model is complete. The schematic diagram of a typical SLS apparatus is given in figure
5.
Figure 5. Selective Laser Sintering System
1.3.3. Fused Deposition Modeling
In Fused Deposition Modeling (FDM) process a movable (x-y movement) nozzle on to a substrate
deposits thread of molten polymeric material. The build material is heated slightly above
14. 7
(approximately 0.5 C) its melting temperature so that it solidifies within a very short time
(approximately 0.1 s) after extrusion and cold-welds to the previous layer as shown in figure 6.
Various important factors need to be considered and are steady nozzle and material extrusion rates,
addition of support structures for overhanging features and speed of the nozzle head, which affects
the slice thickness. More recent FDM systems include two nozzles, one for part material and other
for support material. The support material is relatively of poor quality and can be broken easily
once the complete part is deposited and is removed from substrate. In more recent FDM
technology, water-soluble support structure material is used. Support structure can be deposited
with lesser density as compared to part density by providing air gaps between two consecutive
roads.
Figure 6. Fused Deposition Modeling Process
1.3.4. Laminated Object Manufacturing
Typical system of Laminated Object Manufacturing (LOM) has been shown in figure 9. It can be
seen form the figure that the slices are cut in required contour from roll of material by using a 25-
50 watt CO2 laser beam. A new slice is bonded to previously deposited slice by using a hot roller,
which activates a heat sensitive adhesive. Apart from the slice unwanted material is also hatched
in rectangles to facilitate its later removal but remains in place during the build to act as supports.
Once one slice is completed platform can be lowered and roll of material can be advanced by
winding this excess onto a second roller until a fresh area of the sheet lies over the part. After
15. 8
completion of the part they are sealed with a urethane lacquer, silicone fluid or epoxy resin to
prevent later distortion of the paper prototype through water absorption.
Figure 7. Laminated Object Manufacturing Process
In this process, materials that are relatively cheaper like paper, plastic roll etc. can be used. Parts
of fiber-reinforced glass ceramics can be produced. Large models can be produced and the building
speed is 5-10 times as compared to other rapid prototyping processes. The limitation of the process
included fabrication of hollow models with undercuts and reentrant features. Large amount of
scrap is formed. There remains danger of fire hazards and drops of the molten materials formed
during the cutting also need to be removed.
16. 9
Chapter 2: STERIOLITHOGRAPHY
2.1. Introduction to Steriolithography
The manufacturing of 3D objects by stereolithography is based on the spatially
controlled solidification of a liquid resin by photo-polymerization. Using a computer-
controlled laser beam or a digital light projector with a computer-driven buildi ng
stage, a pattern is illuminated on the surface of a resin. As a result of this, the resin in
the pattern is solidified to a defined depth, causing it to adhere to a support platform.
After photo-polymerization of the first layer, the platform is moved away from the
surface and the built layer is recoated with liquid resin. A pattern is then cured in this
second layer. As the depth of curing is slightly larger than the platform step height, good
adherence to the first layer is ensured (unreacted functional groups on the solidified
structure in the first layer polymerize with the illuminated resin in the second layer) .
These steps (the movement of the platform and the curing of an individual pattern in
a layer of resin) are repeated to construct a solid, three-dimensional object. After
draining and washing-off like most solid freeform fabrication techniques, stereo-
excess resin, an as-fabricated (or green) structure is obtained. In lithography is an
additive fabrication process that allows the fabrication of parts from a computer-
aided design (CAD) file. The designed external and internal (pore) geometry of the
structure that is to be built can either be devised using 3D drawing computer software,
be described using mathematical equations, or be derived from scanning data of
(clinical) imaging technologies such as magnetic resonance imaging (MRI), or
tomography techniques. The possibility to use data from scans makes these
manufacturing technologies particularly useful for many applications in biomedical
engineering, as it enables to fabricate patient-specific models or implants. The CAD-
file describes the geometry and size of the parts to be built. For this, the STL file
format was developed; an STL file lists the coordinates of triangles that together
make up the surface of the designed 3D structure. This designed structure is
(virtually) sliced into layers of the thickness that is used in the layer-by-layer
fabrication process (usually in the range of 25e100 mm). These data are then uploaded
to the stereolithography apparatus (SLA) and the structure is fabricated. This
17. 10
structure, the conversion of reactive groups is usually incomplete, and post-curing
with (stroboscopic) ultraviolet light is often done to improve mechanical properties of
the structures.
To date, most SLA setups in use resemble the ones first developed. Using a computer-
controlled laser beam to draw a pattern, structures are built bottom-up from a support
platform that rests just below the resin surface. Only a thin layer of resin is illuminated
from above, and cured on top of the structure as it is built in a layer-by-layer manner.
A top-down approach is increasingly being applied in stereolithography. In such
setups, light is projected on a transparent, non-adhering plate from underneat h
(the transparent plate forms the bottom of the vessel that contains the resin), and the
support or build platform is dipped.
Figure 8. Steriolithography Manufacturing Setup
2.2. Resins used in stereolithography
The limited number of resins that are commercially available for processing by stereolithography
has often been considered the main limitation of the technique. The resin should be a liquid that
rapidly solidifies upon illumination with light. The first resins developed for use in
stereolithography were based on low-molecular weight polyacrylate or epoxy macromers that form
glassy networks upon photo-initiated polymerization and crosslinking. Several resins have been
18. 11
developed over the past two decades, and the mechanical properties of the networks obtained after
curing cover a wide range. The properties of parts built by stereolithography are continuously
improving, making them not only useful as prototypes but also as functional parts for more
demanding end-use applications. Resins that can be used to create biodegradable devices for
application in medicine are being developed as well, see below.
Most of the available stereolithography resins are based on low molecular weight, multi-functional
monomers, and highly cross-linked networks are formed. These materials are predominantly
glassy, rigid and brittle. Only few resins have been described that allow the preparation of
elastomeric objects by stereolithography. These resin formulations include macromers with low
glass transition temperatures and relatively high molecular weights (1e5 kg/mol), often in
combination with non-reactive diluents such as Nmethylpyrrolidone (NMP) or water to reduce the
viscosity of the resin.
To create polymer-ceramic composite objects, ceramic particles (e.g. alumina or hydroxyapatite)
are homogeneously suspended in the stereolithography resin and photo-polymerized in the SLA.
Processing of the resin is more difficult, as the viscosity of the resin can significantly increase
upon addition of the powder. Maximum ceramic contents of up to 53 wt% have been reported.
Furthermore, the ceramic particle size should be smaller than the layer thickness in the building
process to prepare the objects accurately. The fabricated composite structures are in general,
stiffer and stronger than the polymeric structures. Starting from these composite structures, all-
ceramic objects have been made by first fabricating a composite structure by stereolithography
and then burning out the polymer (pyrolysis) and sintering the ceramic particles.
Different resins have been processed using stereolithography, leading to objects with widely
differing characteristics. Although the number of resins that is available continues to increase, the
technique is still limited to the use of a single resin at a time. (Note that 3D printing and plotting
techniques related to fuse deposition modelling allow the use of multiple cartridges to prepare
structures using different materials simultaneously.) The ability to pattern multiple resins in a
construct (and even within a single layer) is possible in stereolithography too, but complex
sequential polymerization and rinsing steps are required for each layer built. A major technological
challenge lies in developing an automated system to remove uncured resin and exchange resin
19. 12
reservoirs. The restriction to use one resin in stereolithography is perhaps the true major limitation
of the technique.
2.3.New developments in stereolithography and related technologies
Two-photon polymerization is increasingly used in stereo-lithographic fabrication. In two-
photon polymerizations, the photo initiator is excited by the (nearly) simultaneous absorption of
two photons with relatively low intensity, which together introduce enough energy to break the
labile bond and initiate the polymerizations reaction. As a result, two-photon polymerizations is
a non-linear optical process in which the polymerizations rate is proportional to the square of the
laser intensity, as opposed to a linear relationship as is the case for single-photon
polymerizations. This leads to a more localized initiation of the polymerizations, and therefore
to higher resolutions. Using stereolithography setups based on two-photon absorption,
resolutions as high as 200 nm can be obtained.
Holography or interference lithography is a technique in which two or more light sources are
used to create an interference pattern. By superposition of the light waves, regular patterns with
locally varying light intensities are obtained. It is a well-known process for the creation of micro-
and nanostructures like nanopillars, nanostructured substrates, micro frames, 3D photonic
crystals and micro sieves. Interference holography provides a faster and more accurate method
to solidify patterns in a photo-curable resin than can be achieved with stereolithography, and
although it is restricted to a limited number of patterns it could be of interest to prepare repetitive
porous structures for tissue engineering.