This document provides an overview of rapid prototyping (RP) and additive manufacturing. It defines RP as a group of techniques used to quickly fabricate a scale model of a physical part using 3D CAD data. It then covers the history and development of RP, categorizing RP systems as liquid-based, solid-based, or powder-based. The roles of prototypes in product development are discussed, including experimentation, testing, communication, synthesis, and scheduling. Additive manufacturing is introduced as a process of joining materials layer by layer from a 3D model. Popular additive manufacturing materials and applications are briefly outlined.

1. UNIT - 1
INTRODUCTION

3. TYPES OF PROTOTYPE
The general definition of the prototype contains three
aspects of interests:
(1) the implementation of the prototype; from the entire
product (or system) itself to its sub-assemblies and
components,
(2) the form of the prototype; from a virtual prototype to a
physical prototype, and
(3) the degree of the approximation of the prototype;
from a very rough representation to an exact replication
of the product.

4. Overview
FUNDAMENTALS OF
RP
TYPES OF RP
SLAFDM
SLS 3D PRINTER

5. Rapid prototyping
• Rapid prototype is a group of technique used
to quickly fabricate a scale model of physical
part or assemble using a three dimensional
CAD data.

6. FUNDAMENTALS OF RP
Figure 2.1: The Rapid Prototyping Wheel depicting the 4
major aspects of RP

7. 1. Input :
• Input refers to the electronic information required to describe the
physical object with 3D data.
• There are two possible starting points — a computer model or a
physical model.
• The computer model created by a CAD system can be either a
surface model or a solid model.
• On the other hand, 3D data from the physical model is not at all
straightforward. It requires data acquisition through a method
known as reverse engineering.
2. Method :
• The method employed by each vendor can be generally classified
into the following categories:
• photo-curing, cutting and glueing /joining, melting and
solidifying/fusing and joining/binding.
• Photo-curing can be further divided into categories of single laser
beam, double laser beams and masked lamp.

8. 3. Material :
• The initial state of material can come in either solid, liquid or
powder state.
• In solid state, it can come in various forms such as pellets, wire
or laminates. The current range materials include paper, nylon,
wax, resins, metals and ceramics.
4. Application :
• Most of the RP parts are finished or touched up before they
are used for their intended applications.
• Applications can be grouped into (1) Design (2) Engineering,
Analysis, and Planning and (3) Tooling and Manufacturing.
• A wide range of industries can benefit from RP and these
include, but are not limited to, aerospace, automotive,
biomedical, consumer, electrical and electronics products.

9. HISTORY OF RAPID PROTOTYPING

10. HISTORY OF RAPID PROTOTYPING
• In 60’s ,the first rapid prototyping technique
became accessible in the later eighties and used
for production of prototype and model parts.
• In 70’s ,Herbert Voelcker, engineering professor
developed the basic tools of mathematics that
clearly describe the three dimensional aspects
and resulted in the earliest theories of
algorithmic and mathematical theories for solid
modeling.

11. • In 80’s, Carl Deckard ,researcher from the University of
Texas. He pioneered the layer based manufacturing , he
thought of building up the model layer by layer. He
printed 3D models by utilizing laser light for fusing metal
powder in solid prototypes, single layer at a time.
Technique called ‘Selective Laser Sintering’.
• Nowadays , the computer engineer has to simply sketch
the ideas on the computer screen with the help of a
design program that is computer aided. Computer aided
designing allows to make modification as required and
can create a physical prototype that is a precise and
proper 3D object.

12. What is Rapid Prototyping
Rapid Prototyping: Traditional manufacturing:
additive material subtractive material

13. Build
Prototype
Basic process of RP
Three stages: pre-processing, building, and
post processing
RP Process Post ProcessPre Process
Generate
.STL file
Build Supports
if needed
Slicing
Remove
Supports
Clean Surface
Post Cure if needed
Part Completed
CAD Model
Surface/Solid
Model
in RP
systems
in CAD

16. 1. 3D MODELING :
• Advanced 3D CAD modeling is a general prerequisite in RP
processes and, usually is the most time-consuming part of the
entire process chain.
• It is most important that such 3D geometric models can be
shared by the entire design team for many different purposes,
such as interference studies, stress analyses, FEM analysis,
detail design and drafting, planning for manufacturing,
including NC programming, etc.
• There are two common misconceptions amongst new users of
RP
 First, unlike NC programming, RP requires a closed volume of
the model, whether the basic elements are surfaces or solids.
This confusion arises because new users are usually acquainted
with the use of NC programming where a single surface or
even a line element can be an NC element.
 Second, new users also usually assume what you see is what
you get.

17. 2. DATA CONVERSION AND TRANSMISSION :
• The solid or surface model to be built is next converted into a
format dubbed the STL file format.
• This format originates from 3D Systems which pioneers the
STereoLithography system.
• The STL file format approximates the surfaces of the model
using tiny triangles.
• Highly curved surfaces must employ many more triangles,
which mean that STL files for curved parts can be very large.
• This conversion step is probably the simplest and shortest of
the entire process chain.
• However, for a highly complex model coupled with an
extremely low performance workstation or PC, the conversion
can take several hours.

18. 3. CHECKING AND PREPARING :
• The computer term, garbage in garbage out, is also applicable
to RP. Many first time users are frustrated at this step to
discover that their STL files are faulty.
• However, more often than not, it is due to both the errors of
CAD models and the non-robustness of the CAD-STL interface.
• Unfortunately, today’s CAD models — whose quality are
dependent on the CAD systems, human operators and post
processes are still afflicted with a wide spectrum of problems,
including the generation of unwanted shell-punctures.
• At present, the CAD model errors are corrected by human
operators assisted by specialized software such as MAGICS.
• Once the STL files are verified to be error-free, the RP system’s
computer analyzes the STL files that define the model to be
fabricated and slices the model into cross-sections.

19. 4. BUILDING :
• For most RP systems, this step is fully automated. Thus, it is usual for
operators to leave the machine on to build a part overnight.
• The building process may take up to several hours to build
depending on the size and number of parts required.
• The number of identical parts that can be built is subject to the
overall build size constrained by the build volume of the RP system.
5. POST PROCESSING :
• The final task in the process chain is the post processing task. At this
stage, generally some manual operations are necessary. As a result,
the danger of damaging a part is particularly high.
• Therefore, the operator for this last process step has a high
responsibility for the successful process realization.
• The cleaning task refers to the removal of excess parts which may
have remained on the part. Thus, for SLA parts, this refers to excess
resin residing in entrapped portion such as a blind hole of a part, as
well as the removal of supports.

20. Classification of RP
• Three are 3 types of RP systems:
 Liquid-Based
 Solid-Based
 Powder-Based

21. Liquid-Based
• Liquid-based RP systems have the initial form of its material
in liquid state.
• Through a process commonly known as curing, the liquid is
converted into the solid state.
The following RP systems fall into this category:
(1) 3D Systems’ Stereolithography Apparatus (SLA)
(2) Cubital’s Solid Ground Curing (SGC)
(3) Sony’s Solid Creation System (SCS)
(4) CMET’s Solid Object Ultraviolet-Laser Printer (SOUP)
(5) Autostrade’s E-Darts
(6) Teijin Seiki’s Soliform System
(7)Light Sculpting
(8) Aaroflex
(9) Rapid Freeze
(10) Two Laser Beams
(11) Microfabrication

22. Solid-Based
• Except for powder, solid-based RP systems are meant to
encompass all forms of material in the solid state.
• In this context, the solid form can include the shape in the
form of a wire, a roll, laminates and pellets.
The following RP systems fall into this category:
(1) Cubic Technologies’ Laminated Object Manufacturing (LOM)
(2) Stratasys’ Fused Deposition Modeling (FDM)
(3) Kira Corporation’s Paper Lamination Technology (PLT)
(4) 3D Systems’ Multi-Jet Modeling System (MJM)
(5) Solidscape’s ModelMaker and PatternMaster
(6) Beijing Yinhua’s Slicing Solid Manufacturing (SSM), Melted
Extrusion Modeling (MEM) and Multi-Functional RPM Systems
(M-RPM)
(7) CAM-LEM’s CL 100

23. Powder-Based
• In a strict sense, powder is by-and-large in the solid state.
However, it is intentionally created as a category outside the
solid-based RP systems to mean powder in grain-like form.
The following RP systems fall into this category:
(1) 3D Systems’s Selective Laser Sintering (SLS)
(2) EOS’s EOSINT Systems
(3) Z Corporation’s Three-Dimensional Printing (3DP)
(4) Optomec’s Laser Engineered Net Shaping (LENS)
(5) Soligen’s Direct Shell Production Casting (DSPC)
(6) Fraunhofer’s Multiphase Jet Solidification (MJS)
(7) Acram’s Electron Beam Melting (EBM)
(8) Aeromet Corporation’s Lasform Technology
(9) Precision Optical Manufacturing’s Direct Metal Deposition (DMDTM)
(10) Generis’ RP Systems (GS)
(11) Therics Inc.’s Theriform Technology
(12) Extrude Hone’s PrometalTM 3D Printing Process

25. RP Technology in Product Development
• The roles that prototypes play in the product development
process are several.
They include the following:
(1) Experimentation and learning
(2) Testing and proofing
(3) Communication and interaction
(4) Synthesis and integration
(5) Scheduling and markers

26.  Experimentation and learning
To the product development team, prototypes can be used to help the
thinking, planning, experimenting and learning processes whilst designing the
product.
Questions and doubts regarding certain issues of the design can be
addressed by building and studying the prototype.
For example, in designing the appropriate elbow-support of an office
chair, several physical prototypes of such elbow supports can be built to learn
about the “feel” of the elbow support when performing typical tasks on the
office chair.
 Testing and proofing
Prototypes can also be used for testing and proofing of
ideas and concepts relating to the development of the product
For example, in the early design of folding reading glasses
for the elderly, concepts and ideas of folding mechanism can be
tested by building rough physical prototypes to test and prove
these ideas to see if they work as intended.

27.  Communication and interaction
The prototype also serves the purpose of communicating
information and demonstrating ideas, not just within the product
development team, but also to management and client.
A three-dimensional representation is often more superior
than that of a two-dimensional sketch of the product.
For example, a physical prototype of a cellular phone can be
presented to carefully selected customers. Customers can handle
and experiment with the phone and give feedback to the
development team on the features of and interactions with the
phone, thus providing valuable information for the team to improve
its design.

28. Synthesis and integration
A prototype can also be used to synthesize the entire
product concept by bringing the various components and sub-
assemblies together to ensure that they will work together.
This will greatly help in the integration of the product and
surface any problems that are related to putting the product
together.
An example is a complete or comprehensive functional
prototype of personal digital assistant (PDA). When putting the
prototype together, all aspects of the design, including
manufacturing and assembly issues will have to be addressed,
thus enabling the different functional members of the product
development team to understand the various problems associated
with putting the product together.

29. Scheduling and markers
Prototyping also serves to help in the scheduling of the
product development process and is usually used as markers for
the end or start of the various phases of the development effort.
Each prototype usually marks a completion of a particular
development phase, and with proper planning, the development
schedule can be enforced.
It should be noted that in many companies, prototypes do
not necessary serve all these roles concurrently, but they are
certainly a necessity in any product development project.

30. What is Additive Manufacturing?
 The process of joining materials to make objects from three-
dimensional (3D) model data, usually layer by layer
 Commonly known as “3D printing”
 Manufacturing components with virtually no geometric limitations or
tools.
 AM uses an additive process
 Design for manufacturing to manufacturing for design
 Distinguished from traditional subtractive machining techniques
30

31. Functional principle
 The system starts by applying a thin layer of the powder material to the
building platform.
 A powerful laser beam then fuses the powder at exactly the points
defined by the computer-generated component design data.
 Platform is then lowered and another layer of powder is applied.
 Once again the material is fused so as to bond with the layer below at
the predefined points. 31

32. ADVANTAGES
 Freedom of design
 Complexity for free
 Potential elimination of tooling
 Lightweight design
 Elimination of production steps
DISADVANTAGES
 Slow build rates
 High production costs
 Considerable effort required for application design
 Discontinuous production process
 Limited component size.
32

33. Applications
AM has been used across a diverse array of
industries, including;
 Automotive
 Aerospace
 Biomedical
Consumer goods and many others
33

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Additive Manufacturing
AM Materials
However, there are now way too many proprietary materials from the many different 3D printer vendors
to cover them all here.
Instead, we will look at the most popular types of material in a more generic way. And also a couple of
materials that stand out.
Liquid Based Powder Based Solid Based

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Additive Manufacturing
AM Materials
Nylon, or Polyamide, is commonly used in powder form with the sintering process or in filament form
with the FDM process. It is a strong, flexible and durable plastic material that has proved reliable for 3D
printing. It is naturally white in colour but it can be coloured — pre- or post printing. This material can
also be combined (in powder format) with powdered aluminium to produce another common 3D
printing material for sintering Alumide.
ABS is another common plastic used for 3D printing, and is widely used on the entry-level FDM 3D
printers in filament form. It is a particularly strong plastic and comes in a wide range of colours.
ABS can be bought in filament form from a number of non- propreitary sources, which is another reason
why it is so popular.
PLA is a bio-degradable plastic material that has gained traction with 3D printing for this very reason. It
can be utilized in resin format for DLP/SL processes as well as in filament form for the FDM process. It
is offered in a variety of colours, including transparent, which has proven to be a useful option for some
some applications of 3D printing. However it is not as durable oras flexible as ABS.

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Additive Manufacturing
AM Materials
LayWood is a specially developed 3D printing material for entry- level extrusion 3D printers. It comes
in filament form and is a wood/polymer composite (also referred to as WPC).
A growing number of metals and metal composites are used for industrial grade 3D printing. Two of the
most common are aluminium and cobalt derivatives.
One of the strongest and therefore most commonly used metals for 3D printing is Stainless Steel in
powder form for the sintering/ melting/EBM processes. It is naturally silver, but can be plated with other
materials to give a gold or bronze effect.
In the last couple of years Gold and Silver have been added to the range of metal materials that can be
3D printed directly, with obvious applications across the jewellery sector. These are both very strong
materials and are processed in powder form.
Titanium is one of the strongest possible metal materials and has been used for 3D printing industrial
applications for some time.
Supplied in powder form, it can be used for the sintering/melting/ EBM processes.

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Additive Manufacturing
AM Materials
Ceramics
Ceramics are a relatively new group of materials that can be used for 3D printing with various levels of
success. The particular thing to note with these materials is that, post printing, the ceramic parts need to
undergo the same processes as any ceramic part made using traditional methods of production - namely
firing and glazing.
Paper
Standard A4 copier paper is a 3D printing material employed by the proprietary SDL process supplied
by Mcor Technologies. The company operates a notably different business model to other 3D printing
vendors, whereby the capital outlay for the machine is in the mid-range, but the emphasis is very much
on an easily obtainable, cost-effective material supply, that can be bought locally. 3D printed models
made with paper are safe, environmentally friendly, easily recyclable and require no post-processing.
Bio Materials
There is a huge amount of research being conducted into the potential of 3D printing bio materials for a
host of medical (and other) applications. Living tissue is being investigated at a number of leading
institutions with a view to developing applications that include printing human organs for transplant, as
well as external tissues for replacement body parts. Other research in this area is focused on developing
food stuffs - meat being the prime example.

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Additive Manufacturing
AM Materials
Bio Materials
There is a huge amount of research being conducted into the potential of 3D printing bio materials for a
host of medical (and other) applications. Living tissue is being investigated at a number of leading
institutions with a view to developing applications that include printing human organs for transplant, as
well as external tissues for replacement body parts.
Food
Experiments with extruders for 3D printing food substances has increased dramatically over the last
couple of years. Chocolate is the most common (and desirable). There are also printers that work with
sugar and some experiments with pasta and meat. Looking to the future, research is being undertaken, to
utilize 3D printing technology to produce finely balanced whole meals.
Other
And finally, one company that does have a unique (proprietary) material offering is Stratasys, with its
digital materials for the Objet Connex 3D printing platform. This offering means that standard Objet 3D
printing materials can be combined during the printing process — in various and specified
concentrations to form new materials with the required properties. Up to 140 different Digital Materials
can be realized from combining the existing primary materials in different ways.
Concrete

39. Materials of Additive Manufacturing
• Nylon
• ABS
• PLA
• Laywood
• Ceramic
• Biomaterials
• concrete

40. Economics of Additive Manufacturing
• Less waste
• No tooling cost
• Smaller production runs
• Large scale customization
• Eliminates lead time