Intro to rapid prototyping

1. UNIT 1
INTRODUCTION
TO
ADDITIVE
MANUFACTURING

2. INTRODUCTION
 The competition in the world market for manufactured
products has intensified tremendously in recent years.
 It has become important, if not vital, for new products to
reach the market as early as possible, before the
competitors .

3. INTRODUCTION
 To bring products to the market swiftly, many of the
processes involved in the design, test, manufacture and
market of the products have been squeezed, both in terms
of time and material resources.

4. INTRODUCTION
 Many of the tools and effective approaches have been
evolved in the market to bring the product swiftly in to
the market.
 These tools are almost technology driven involving
computers.
 As a result there is so much advancement in
technologies over last few decades.

5. DEFINITION
 The process of joining materials to make objects from three-
dimensional (3D) model data, usually layer by layer.
 Commonly known as “3D printing”
 AM uses an additive process

7. 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. 5

8. DEFINITION OF PROTOTYPE
 According to Oxford Advanced Learners Dictionary
of current English
 A prototype is the first or original example of
something that has been or will be copied or
developed
 It is a model or preliminary version
 General definition in design terms would be an
approximation of a product or system or its
components in some form for a definite purpose in
its implementation

9. PROTOTYPES ARE USED FOR THE FOLLOWING
PURPOSES
Experimentation and learning while designing
Testing and proofing of ideas and concepts
Communication and interaction among design teams
Synthesis and integration of the entire product concept

10. CLASSIFICATION OF PROTOTYPES
 Implementation:
Complete prototypes will model most of the characteristics
of the final product.
The prototypes are usually full-scale and they are also
usually fully functional.

11. CLASSIFICATION OF PROTOTYPES
Prototypes can be partially functional in nature.
These prototypes are either needed to study and
investigate special problems associated with a single
component or sub-assembly, or they are needed to study
and validate a concept that requires close attention.

12. CLASSIFICATION OF PROTOTYPES
 Form:
 Physical prototypes
 Virtual prototypes

13. CLASSIFICATION OF PROTOTYPES
FORM:
Physical prototypes are tangible, and are built for
the purpose of testing, experimentation or aesthetic
and human factors evaluation.
Physical prototypes can be manufactured using AM
techniques, or other methods which tend to be less
sophisticated, craft-based and largely labour-
intensive.
An example is the mock-up of a mobile phone.

14. CLASSIFICATION OF PROTOTYPES
 Form:
Virtual prototypes are non-tangible, and they are used when the
physical prototype are too large, too expensive or too time-consuming
to produce.
 Virtual prototypes are based purely upon the assumed principles or
science at that point in time, and are completely unable to predict any
unexpected phenomenon. Nowadays, virtual prototypes can be
stressed, tested, analysed and modified as if they were physical
prototypes.
 An example is the visualisation of airflow over an aircraft wing.

15. CLASSIFICATION OF PROTOTYPES
 Degree of approximation:
Prototypes can be very rough representations of
the intended final product.
The prototype is therefore used for testing and
studying certain problems that can arise from
product development.

16. CLASSIFICATION OF PROTOTYPES
 Alternatively the prototype can be an exact full-scale
representation of the product, modelling every aspect
of the product.
 This type of prototype becomes more and more important
towards the end-stage of the product development
process.

17. FUNDAMENTALS OF AM
1. A model or component is modelled on a Computer-
Aided Design and Computer-Aided Manufacturing
(CAD/CAM) system.
 The model, which describes the physical part to be built,
must be represented as closed surfaces which
unambiguously define an enclosed volume. This means
that the data must specify the inside, the outside and the
boundary of the model.

18. FUNDAMENTALS OF AM
2. The solid or surface model to be built is next converted
into a format called the .STL file format which originated
from 3D Systems.
 The STL file format approximates the surfaces of the
model using the simplest of polygons and triangles.
 Some AM systems also accept data in the IGES (Initial
Graphics Exchange Specification)
format, provided it is of the correct "flavour".

19. FUNDAMENTALS OF AM
3. A computer program analyses a STL file that defines the
model to be fabricated and “slices” the model into cross
sections.
The cross sections are systematically recreated through
the solidification of either liquids or powders and then
combined to form a 3D model.
Another possibility is that the cross sections are already
thin, solid laminations and these thin laminations are glued
together with adhesives to form a 3D model.

20. FOUR KEY ASPECTS OF AM
 INPUT
 METHOD
 MATERIAL
 APPLICATIONS

21. INPUT
 Input refers to the electronic information required to
describe the object in 3D.
 There are two possible starting points —
 a computer model
a physical model or part.
 The computer model created by a CAD system can be
either a surface model or a solid model.
 .

22. INPUT
 On the other hand, 3D data from the physical model is not
so straightforward.
 It requires data acquisition through a method known as
reverse engineering.
 Equipment, such as coordinate measuring machines
(CMM) or laser digitisers, are used to capture data points
of the physical model, usually in a raster
format, and then to “reconstruct” it in a CAD system

23. METHOD
 They are currently more than 50 vendors for AM systems
 The method employed by each vendor can be generally
classified into the following categories:

(1) Photo-curing

(2) Cutting and joining

(3) Melting and solidifying or fusing

(4) Joining or binding
.

24. MATERIAL
 The raw materials can come in one of the following
forms:
 Solid, Liquid or Powder state.
 Solid materials come in various forms such as pellets,
wire or laminates.
 The current range of materials includes paper,
polymers, wax, resins, metals and ceramics.

25. APPLICATIONS
 Most of the AM 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
(3) manufacturing and tooling.
 Aerospace, automotive, biomedical, consumer,
electrical and electronic products.

26. AM WHEEL

27. HISTORICAL DEVELOPMENT

In 1987, the first commercial AM system, stereolithography
apparatus (SLA)-1, was launched by 3D Systems in the United
States.
 It worked on the principle of stereolithography (STL) and for the
first time enabled users to generate a physical object from
digital data.
 The invention of AM technology was a "watershed event”
because of the tremendous time saved by not machining parts,
especially for complicated and difficult-to-produce models.
 Since then, other new AM technologies have been
commercialised, including Fused Deposition Modelling (FDM)
and Selective Deposition Lamination (SDL)
in 1991, as well as Selective Laser Sintering (SLS) in 1992.

28. HISTORICAL DEVELOPMENT
 In 1993, Soligen brought Direct Shell Production Casting
to the market and 3D Systems also introduced QuickCast
(a method of producing indirect tooling from AM), as the
potential savings in time and
resources that AM can bring became apparent.
 Companies such as General Motors were early adopters
of AM.
 They acquired the SLA-250 (the model immediately
following SLA-1) in 1991, and used it for rapid
tooling and prototyping of parts such as cranking motor
nose housings and connector feeder tracks

29. HISTORICAL DEVELOPMENT
 3D printers based on technology similar to inkjet printers
began to appear in the market in 1996.
 In 1998, Optomec sold its first Laser Engineered Net
Shaping (LENS) metal powder system as the LENS
process was capable of producing fully dense metal parts
with no voids within the metal.
 In 1999, selective laser melting (SLM) system was
introduced by Fockele & Schwarze of Germany. Since
2000, there have been many more AM systems entering
the market.
 .

30. HISTORICAL DEVELOPMENT
 While some companies such as Boeing were already
using AM to produce parts such as electrical boxes,
brackets and environmental control system ducting, the
development of international standards was expected to
help different companies coordinate AM research and
commercialisation efforts and further increase the use of
AM for direct manufacturing

31. ADVANTAGES OF AM
 Today's automated, tool-less, pattern-less AM systems
can directly produce functional parts in small production
quantities.
 Parts produced in this way usually have an accuracy and
surface finish inferior to those made by machining.
 However, some advanced systems are able to
produce near tooling quality parts that are close to or are
in the final shape.
 More importantly, the time taken to manufacture any part
— once the design data are available — is short, and can
be a matter of hours.

32. DIRECT BENEFITS
 AM has ability to produce physical models of any
complexity in relatively short time.
 In the last 40 years, products realised to the market
place have become increasingly complex in shape
and form.
For instance, compare the aesthetically beautiful
car body of today with that of the 1970s.

33. DIRECT BENEFITS
 On a relative complexity scale of 1-3 , it can be noted that
from a base of 1 in 1970, this relative complexity index
has increased to about 2 in 1980, approached 3 in the 1990s,
and exceeded 3 after 2000.
 However, the relative project completion times
have not correspondingly increased.
 It increased from an initial base of about 4 weeks' project
completion time in 1970 to 16 weeks in 1980.
 However, with the use of CAD/CAM and computer numerical
control (CNC) technologies, project completion time was
reduced to 8 weeks.
Eventually, AM systems allowed the project manager to
further cut the completion time to less than 2 weeks in 2015.

34. DIRECT BENEFITS

35. BENEFITS TO PRODUCT DESIGNERS

Product designers can increase part complexity
 More organic, sculptured and complex shapes for
functional or aesthetic features can be
accommodated.
 They can optimise part design to meet customer
requirements

36. BENEFITS TO PRODUCT DESIGNERS
 Product Designers can reduce parts count by
combining features into single-piece parts
 With fewer parts, the time spent on tolerance analysis,
selecting fasteners, detailing screw holes and assembly
drawings is greatly reduced.
Product designers can minimise the use of material and
optimise strength/weight ratios without regards to
machining cost.
 Finally, they can minimise time-consuming
discussions and evaluations of manufacturing
possibilities.

37. BENEFITS TO MANUFACTURING ENGINEERS
 The manufacturer can reduce the labour content of
manufacturing, since part-specific setting up and
programming are eliminated, machining or
casting labour is reduced, and inspection and assembly
are consequently minimised as well.
 Reducing material waste, waste disposal costs,
material transportation costs and inventory cost for raw
stock and finished parts (producing only as many parts
as required reduces storage requirements) can
contribute to lower overheads.
 Fewer inventories are scrapped because of fewer design
changes, and the risks of disappointing sales are
reduced.

38. BENEFITS TO MANUFACTURING ENGINEERS
 In addition, the manufacturer can simplify purchasing
since there is only one form of raw material: a spool of
wire, a vat of liquid, and so on.
 The production manager can purchase one general
purpose machine rather than many specialised
machines, and therefore reduce capital equipment and
maintenance expenses and minimise the need for
specialised operators and training.

39. BENEFITS TO MANUFACTURING ENGINEERS
 Furthermore, one can reduce the inspection reject rate
since the number of tight tolerances required where
parts must mate can be reduced.
 One can avoid design misinterpretations (instead, "what
you design is what you get"), quickly change design
dimensions to deal with tighter tolerances and achieve
higher part repeatability, since tool wear is eliminated.

40. COMMONLY USED TERMS AND DEFINITIONS
OF AM

There are many terms used by the engineering
communities around the world to describe this
technology.
 3D Printing
 Rapid Prototyping

41. COMMONLY USED TERMS AND DEFINITIONS
OF AM
 Some of the less commonly used terms include
 Direct CAD Manufacturing
 Desktop Manufacturing
 Instant Manufacturing
 CAD Oriented Manufacturing
 The rationale behind these terms is based on AM's
speed, ease and convenience.

42. COMMONLY USED TERMS AND DEFINITIONS
OF AM
 Another group of terms emphasises the unique
characteristic of AM layer-by-layer addition of
material.
 Layer Manufacturing,
 Material Deposit Manufacturing,
 Material Addition Manufacturing
 Material Increase Manufacturing.

43. COMMONLY USED TERMS AND DEFINITIONS
OF AM
 There is yet another group of terms which chooses
to focus on the word "freeform” –
 Solid Freeform Manufacturing and
 Solid Freeform Fabrication.

44. CLASSIFICATION OF AM SYSTEMS

ISO/ASTM, in its most recent ISO/ASTM 52900 General
Principles Terminology standards manual, has classified
all AM processes into seven broad categories.

45. CLASSIFICATION OF AM SYSTEMS
1) Vat Photo polymerisation / Stereolithography
2) Material Jetting
3) Binder jetting
4) Material extrusion
5) Powder bed fusion
6) Sheet lamination
7) Directed energy deposition

46. HISTORY OF STEREO LITHOGRAPHY
 Hideo Kodama and Chuck Hill, French Scientists introduced
this concept in 1980.
 The term stereo lithography was coined by Chuck
 He patented the process
 He is called the father of 3D Printing
 He founded first 3D printing company
 SLA-1 was the first machine developed by company in 1987

47. VAT PHOTO POLYMERIZATION/
STEREOLITHOGRAPHY
 SLA has 4 parts
 Vat/ tank with photopolymer
 A platform /elevator that is lowered into tank
 An UV Laser
 Computer controlling the platform and the laser

48. VAT PHOTO POLYMERIZATION/
STEREOLITHOGRAPHY

49. VAT PHOTO POLYMERIZATION/
STEREOLITHOGRAPHY
4
9
• Laser beam traces a cross-section of the part pattern
on the surface of the liquid resin
• SLA's elevator platform descends
• A resin-filled blade sweeps across the cross section of
the part, re-coating it with fresh material
• Immersed in a chemical bath
 Stereolithography requires the use of supporting
structures

50. MATERIAL JETTING
5
0
• Drop on demand method
• The print head is positioned above build platform
• Material is deposited from a nozzle which moves
horizontally across the build platform
• Material layers are then cured or hardened using
ultraviolet (UV) light
• Droplets of material solidify and make up the first layer.
• Platform descends
• Good accuracy and surface finishes

51. MATERIAL JETTING

52. BINDER JETTING
• Binder jetting process uses two materials
• Build material and binder
• Commonly used build materials are metals , sand, ceramics
etc.
• Binder is selectively deposited onto the powder bed,
bonding these areas together to form a solid part one layer at
a time.
5
2

53. BINDER JETTING
• A glue or binder is jetted from an inkjet style printhead
• Roller spreads a new layer of powder on top of the
previous layer
• The subsequent layer is then printed and is stitched
to the previous layer by the jetted binder
• The remaining loose powder in the bed supports
overhanging structures

54. BINDER JETTING

55. MATERIAL EXTRUSION/FDM
5
5
• Fuse deposition modelling (FDM)
• Material is drawn through a nozzle, where it is heated and is then
deposited layer by layer
• First layer is built as nozzle deposits material where required onto
the cross sectional area.
• The following layers are added on top of previous layers.
• Layers are fused together upon deposition as the material is in a
melted state.

56. MATERIAL EXTRUSION/FDM

57. POWDER BED FUSION
• Selective laser sintering (SLS)
• Selective laser melting (SLM)
• Electron beam melting (EBM)
No support structures required
• A layer, typically 0.1mm thick of material is spread over the build
platform.
• The SLS machine preheats the bulk powder material in the
powder bed
• A laser fuses the first layer
• A new layer of powder is spread.
• Further layers or cross sections are fused and added.
• The process repeats until the entire model is created.
5
7

58. POWDER BED FUSION

59. SHEET LAMINATION
PROCESS
• Metal sheets are used
• Laser beam cuts the by hotcontour of each layer
• Glue activated rollers
1. The material is positioned in place on the cutting bed.
2. The material is bonded in place, over the previous layer,
using the adhesive.
3. The required shape is then cut from the layer, by laser
or knife.
4. The next layer is added.
59

60. SHEET LAMINATION PROCESS

61. DIRECTED ENERGY DEPOSITION
• Consists of a nozzle mounted on a multi axis arm
• Nozzle can move in multiple directions
• Material is melted upon deposition with a laser or electron
beam
PROCESS
1. A4 or 5 axis arm with nozzle moves
around a fixed object.
2. Material is deposited from the nozzleonto
existing surfaces of the object.
3. Material is either provided in wire or
powder form.
4. Material is melted using a laser, electron
beam or plasma arc upon deposition.
5. Further material is added layer by layer
and solidifies, creating or repairing new
material features on the existing object. 15