Rapid prototyping

2. 
 In many fields, there is great uncertainty as to
whether a new design will actually do what is
desired. New designs often have unexpected
problems. A prototype is often used as part of the
product design process to allow engineers and
designers the ability to explore design alternatives,
test theories and confirm performance prior to
starting production of a new product. Engineers use
their experience to tailor the prototype according to
the specific unknowns still present in the intended
design.
Introduction

3. 
 Rapid Prototyping technology employs
various engineering e.g. computer control and
software techniques including laser, optical
scanning, photosensitive polymers, material
extrusion and deposition, powder metallurgy etc. to
directly produce a physical model layer by layer
(Layer Manufacturing) in accordance with the
geometrical data delivered from a 3D CAD model.
Definition

5. 
Differences between conventional machining
and rapid prototyping

6. 
 Prototyping can improve the quality of requirements and
specifications provided to developers.
 Reduced time and costs:
 Users are actively involved in the development.
 Quicker user feedback is available leading to better
solutions.
 Errors can be detected much earlier.
 Missing functionality can be identified easily.
WHY Rapid prototyping?

7. 
 High precision RP machines are still expensive.
 RP systems are difficult to build parts with accuracy
under +/- 0.02mm and wall thickness under 0.5mm.
 The physical properties of the RP parts are normally
inferior to those samples that made in proper materials
and by the traditional tooling.
 The RP parts are not comparable to (CNC) prototype
parts in the surface finishing, strength, elasticity,
reflective index and other material physical properties.
Limitations of Rapid prototyping

8. 
All RP techniques employ the basic five-steps
processes:
1. Create a CAD model of the design.
2. Convert the CAD model to STL format.
3. Slice the STL file into thin cross-sectional layers.
4. Construct the model one layer atop another.
5. Clean and finish the model.
Workflow of RP processes

9. 
Surface/Solid
model
Generate STL
file
Build supports
if needed
Slicing
Build
prototype
Remove
supports
Clean the
surface
Post cure
Part
completed
CAD model Pre process RP process Post process
Workflow of RP processes

10. 
 First, the object to be built is modeled using a
Computer-Aided Design (CAD) software package.
 Solid modelers, such as Pro/ENGINEER, tend to
represent 3-D objects more accurately than wire-frame
modelers such as AutoCAD, and will therefore yield
better results.
 This process is identical for all of the RP build
techniques.
1. CAD Model Creation

11. 
 To establish consistency, the STL format has been adopted
as the standard of the rapid prototyping industry.
 The second step, therefore, is to convert the CAD file into
STL format. This format represents a three-dimensional
surface as an assembly of planar triangles
 STL files use planar elements, they cannot represent
curved surfaces exactly. Increasing the number of
triangles improves the approximation
2. Conversion to STL Format

12. Example of STL model
This figure shows a typical
example of STL model
which is composed of
triangles and each triangle is
described by a unit normal
vector direction and three
points representing the
vertices of the triangle.

13. 
 In the third step, a pre-processing program
prepares the STL file to be built.
 The pre-processing software slices the STL model
into a number of layers from 0.01 mm to 0.7 mm
thick, depending on the build technique.
 The program may also generate an auxiliary
structure to support the model during the build.
Supports are useful for delicate features such as
overhangs, internal cavities, and thin-walled
sections.
3. Slice the STL File

14. Desired part or
model geometry
Without supports,
overhanging areas of part
may peel away and damage
the whole model

15. 
 The fourth step is the actual construction of the part.
 RP machines build one layer at a time from
polymers, paper, or powdered metal.
 Most machines are fairly autonomous, needing little
human intervention.
4. Layer by Layer Construction

16. 
 The final step is post-processing. This involves
removing the prototype from the machine and
detaching any supports.
 Some photosensitive materials need to be fully
cured before use
 Prototypes may also require minor cleaning and
surface treatment.
 Sanding, sealing, and/or painting the model will
improve its appearance and durability.
5. Clean and Finish

17. 
Types of Rapid Prototyping
Technologies
 SLA --- Stereolithography
 SLS --- Selective Laser Sintering
 LOM --- Laminated Object Manufacturing
 FDM --- Fused Deposition Modeling
 3DP --- Three Dimensional Printing

18. 
 Patented in 1986, Stereolithography started the
rapid prototyping revolution. The technique builds
three-dimensional models from liquid photosensitive
polymers that solidify when exposed to ultraviolet
light.
1. Stereolithography (SLA)

19. Schematic diagram of Stereolithography process

20. Laser – concentrative UV beam to transom liquid
into solid state.
Elevator – control the movement of platform
upward and downward
Platform – a steel plate with plenty of holes as
the basement for part building
Resin vat – contain raw material to form SLA
model
Mirrors – control the path of movement of the
laser beam at X and Y axis
Sensor – locate the coordinate and instant power
of the laser beam and feedback to the control unit
for fine adjustment
Mirrors
sensor
Basic components of SLA system

22. 
2. Selective Laser Sintering (SLS)

23.  Advantages
◦Flexibility of materials used
• PVC, Nylon, Sand for building sand casting cores, metal and
investment casting wax.
◦No need to create a structure to support the part
◦Parts do not require any post curing except when ceramic is used.
 Disadvantages
◦During solidification, additional powder may be hardened at the
border line.
◦The roughness is most visible when parts contain sloping (stepped)
surfaces.
 Application Range
◦Visual Representation models
◦Functional and tough prototypes
◦cast metal parts

24. 
 As the name implies the process laminates thin
sheets of film (paper or plastic).
 The laser has only to cut/scan the periphery of each
layer.
3. Laminated Object Manufacture (LOM)

25. The process
 The build material (paper with a
thermo-setting resin glue on its
under side) is stretched from a
supply roller across an anvil or
platform to a take- up roller on
the other side.
 A heated roller passes over the
paper bonding it to the platform
or previous layer.
 A laser, focused to penetrate
through one thickness of paper
cuts the profile of that layer. The
excess paper around and inside
the model is etched into small
squares to facilitate its removal.

26.  The process continued:
 The process of gluing and cutting continuous
layer by layer until the model is complete.
 To reduce the build time, double or even
triple layers are cut at one time which
increases the size of the steps on curved
surfaces and the post processing necessary to
smooth those surfaces.

27.  Advantages
o Wide range of materials
o Fast Build time
o High accuracy
o LOM objects are durable, multilayered structures which can be
machined, sanded, polished, coated and painted
 Application Range
o Used as precise patterns for secondary tooling processes such as
rubber molding, sand casting and direct investment casting.
o Medical sector for making instruments.

28. 
4. Fused Deposition Modeling (FDM)
FDM 2000 Specifications Prodigy Specifications
Build Volume: 10" x 10" x 10"
Materials: ABS, Casting Wax
Build Step Size: 0.005" to
0.030"
Build Volume: 8" x 8" x 10"
Materials: ABS, Casting Wax
Build Step Size: 0.007", 0.010", 0.013"
Up to 4x faster than the FDM 2000

29.  (FDM) is a solid-based rapid prototyping method that
extrudes material, layer-by-layer, to build a model.
 A thread of plastic is fed into an extrusion head, where it
is heated into a semi-liquid state and extruded through a
very small hole onto the previous layer of material.
 Support material is also laid down in a similar manner.

30.  Advantages
o Easy fabrication
o Minimal wastage
o Ease of removal
o Easy handling
 Application Range
o Designing
o Engineering analysis and planning
o Tooling and manufacturing

31. How Rapid Prototyping Technologies Compare?

32. 
 What is 3DP?
3DP is the process of creating an object using a
machine that puts down material layer by layer in
three dimensions until the desired object is formed.
A 3D printer extrudes melted plastic filament or
other material, building objects based on
specifications that come from modeling software or
from a scan of an existing object.
5. Three Dimensional Printing
(3DP)

34. 
 To create something with a 3D printer, a user begins either by scanning an
existing object with a 3D scanner to obtain the needed specifications or by
generating the specs in a 3D modeling application.
 The specifications are then sent to an extrusion printer, where plastic filament
or other material is used to create the three-dimensional model one layer at a
time.
 As the material is extruded from the nozzle of the printer, the software
controlling the machine moves either the platform or the nozzle itself such that
the material is deposited in a succession of layers to create the object. Often, the
completed object is a single color, but printers are now available with two
nozzles for dual-color prints. Printing can take a few minutes for a small object
the size of a keychain or several hours for larger, more complicated objects.
How does 3D printing work?

36. 
 3D Printed technology is being used by some of the most modern
manufacturers to develop prototypes and products going through
testing phase. This has increased the efficiency of product
development. These 3D printing innovations are saving; time,
money and resulting in higher profit margins.
 3D printing technology is gaining in popularity, becoming more
competitive, and increasingly affordable. A lot of businesses and
industries are benefiting. Those employing the new technology
include manufacturers, print advertisers, and commercial marketing
firms who are reaching out to clients with new brilliant ideas.
Why 3D printing?

37.  Some of the most exciting global businesses are already expanding
possibilities by using 3D printers. Coca-Cola created miniature statues of
consumers to promote smaller Coke bottles. Some of the other
companies experimenting with the technology are Nokia, Volkswagen,
and eBay. In retail, say Selfridges and Harvey Nichols in UK, Le Bon
Marché in France, to name a few.
 Biscuits and chocolates can now be 3D printed. It will be very interesting
for food-related businesses to see what their marketers and printers are
actually capable of with no holds barred. Now companies can produce
any design of biscuit with extreme detailing. Since the technology is still
very new and modern, many will be attracted by the amazing designs and
logo printing. This makes these giveaways useful free samples at trade
shows.

38. 
 While initially 3D printing was primarily a technology
for prototyping, this is quickly changing. Now numerous
manufacturers are producing end-use components and
entire products via additive manufacturing. From the
aerospace industry, to medical modeling and
implantation, to prototyping of all kinds, 3D printing is
being used by virtually every major industry on the
planet in one way or another.
3D printing applications

39. 
 3D printed models of human organs have
been a frequent tool for surgeons over the
last two to three years, as they provide a
more intricate view of the issues at hand.
Instead of relying on 2D and 3D images on
a computer screen or a printout, surgeons
can actually touch and feel physical
replicas of the patient’s organs, bone
structures, or whatever else they are about
to work on.
 Additionally, there is research underway
by companies like Organ logy to 3D print
partial human organs such as the liver and
kidney.
Medical
Injured skull

42. 
 3D bio printing, is a powerful fabrication technology, used to
create three-dimensional cellular constructs which bio mimics
complex biological functionalities found in native tissues and
organs.
 The bio printing manufacturing technology combined
with smart biomaterials, stem cells, growth and
differentiation factors, and biomimetic environments have
created unique opportunities to fabricate tissues in the
laboratory from combinations of engineered extracellular
matrices (scaffolds), cells, and biologically active
molecules.
Medical: 3D Bio-Printers

43. Before After
3D printing face operation

44. 
 Actually, 3D printed drugs have a lot of advantages to
regularly manufactured ones. It’s much easier to control
density of a 3D printed drug, and design how porous it
should be, which means that how quickly it dissolves is
much for flexible, and therefore, designers can print a pill
that can be dissolved with one sip of water. Additionally,
they can add more of the active ingredient, all while
making the actual pill much smaller.
3D printed drugs

46. 
 Another general early adopter of Rapid Prototyping technologies,
the earliest incarnation of 3D printing, was the automotive sector.
Many automotive companies particularly at the cutting edge of
motor sport and F1 have followed a similar trajectory to the
aerospace companies. First (and still) using the technologies for
prototyping applications, but developing and adapting their
manufacturing processes to incorporate the benefits of improved
materials and end results for automotive parts.
 Many automotive companies are now also looking at the
potential of 3D printing to fulfill after sales functions in terms of
production of spare/replacement parts, on demand, rather than
holding huge inventories.
Automotive

47. 3D printed car

48. 
3D printed babies

49. 
3D printed art kids

50. 
3D printed eagle beak

51. 
3D printed guns

52. 
3D Printed jet engine

54. 
 Architectural models have long been a staple application
of 3D printing processes, for producing accurate
demonstration models of an architect’s vision. 3D printing
offers a relatively fast, easy and economically viable
method of producing detailed models directly from 3D
CAD, BIM or other digital data that architects use. Many
successful architectural firms, now commonly use 3D
printing (in house or as a service) as a critical part of their
workflow for increased innovation and improved
communication.
Architecture

55. 
 Related technology development began in the 1960s, with pumped
concrete and isocyanine foams.
Building printing refers to various technology that use 3D printing as a
way to construct buildings. Potential advantages of this process
include quicker construction, lower labor costs, and less waste
produced. 3D printing at a large scale may be well suited for
construction of extraterrestrial structures on the Moon or other planets
where environmental conditions are less conducive to human labor-
intensive building practices.
Developments in additive manufacturing technologies have included
attempts to make 3D printers capable of producing structural
buildings.
Related technology development began in the 1960s, with pumped
concrete and isocyanine foams.
Architecture: 3D printed concrete houses

57. 
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