MANUFACTURING PROCESS

1. CHAPTER 19
Rapid Prototyping Operations

2. Rapid prototyping
• Introduction
• Subtractive processes
• Additive process
• Virtual Prototyping
• Applications

3. Rapid prototyping
• Technology which considerably speeds the iterative product
development process
Fig: a) Examples of parts made by rapid prototyping b) Stereolithography model of cellular phone

4. Advantages
• CAD data files can be manufactured in hours.
• Tool for visualization and concept verification.
• Prototype used in subsequent manufacturing
operations to obtain final part
• Tooling for manufacturing operations can be
produced

5. Classification of Rapid Prototyping
• Rapid prototyping is classified to 3-major groups
Subtractive ( Removal of material )
Additive ( Adding of material )
Virtual ( Advanced computer base
visualization)

6. Subtractive Process
• Subtractive process use computer based Prototype technology to
speed the process
• Essential Technologies for subtractive prototyping :
• Computer – based drafting packages ( 3-D representation of parts)
• Interpretation software (Translation of cad file to manufacturing
software)
• Manufacturing Software (Planning Machining operations)
• Computer-Numerical Control Machinery

7. Additive Process
• Build parts in layer by layer (slice by slice as stacking a loaf of bread)
Fig: The computational steps in
producing a stereolithography
file a) Three dimensional
description of part b)The part
is divides into slices (only one
in 10 is shown) c)support
material is planned d)A set of
tool directions is determined to
manufacture each slice.
Shown is the extruder path at
section A-A from c) For a
fused-deposition-modeling
operation

8. Require elaborate software
1 : Obtain cad file
2 : Computer then constructs slices of a 3-dimensional
part
3 : slice analyzed and compiled to provide the rapid
prototyping machine
4 : setup of the proper unattended and provide rough
part after few hours
5 : Finishing operations and sanding and painting
6:labor intensive and production time varies from few
minutes to few hours
Additive Process

9. Fused Deposition Modeling
• A gantry robot controlled extruder
head moves in two principle
directions over a table
• Table can be raised or lowered as
needed
• Thermo plastic or wax filament is
extruded through the small orifice
of heated die
• Initial layer placed on a foam
foundation with a constant rate
• Extruder head follows a
predetermined path from the file
• After first layer the table is
lowered and subsequent layers are
formed
Fig : (a)Fused-deposition-modeling process.
(b)The FDM 5000, a fused-decomposition-
modeling-machine.

10. Fused Deposition Modeling
Fig: a)A part with protruding section which requires support material b) Common support structures used in
rapid-prototyping machines

11. Stereolithiography
• Works based on the principle of
curing liquid photomer into specific
shape
• A vat which can be lowered and
raised filled with photocurable liquid
acrylate polymer
• Laser generating U-V beam is
focused in x-y directions
• The beam cures the portion of photo
polymer and produces a solid body
• This process is repeated till the level
b is reached as shown in the figure
• Now the plat form is lowered by
distance ab
• Then another portion of the cylinder
is shaped till the portion is reached
Fig :Stereolithiography Process

12. Selective laser sintering (SLS) :
Fig: The selective laser sintering process

13. Selective laser sintering
• SLS based on sintering of nonmetallic powders onto a
selective individual objects
• Basic elements in this process are bottom of processing
chambers equipped with 2 cylinders
• Powder feed cylinder which is raised incrementally to
supply powder to part-build cylinder through a roller
mechanism
• Part-build cylinder which is lowered incrementally to where
the sintered part is formed.

14. • Set of the proper computer files and the initiation of
the production processes
• Machine operate unattended and provide rough part
after few hours
• Finishing operations as sanding and painting
• Labor intensive & production time varies from few
minutes to few hours
Selective laser sintering

15. • Layer of powder is first deposited on part build
cylinders
• A laser beam controlled by instruction from 3-
D file is focused on that layer tracing &
sintering a particular cross-section into a solid
mass & dust is taken off.
• Another layer of powder is now deposited this
cycle is repeated again and dust is shaken off
Selective laser sintering

16. Solid Base curing :
• Also called Solid ground
curing
• Entire slices of part are
manufactured at one time
• So large throughput is
achieved
• Most expensive & time
consuming
• The entire process is shown
Fig:The solid based curing process

17. • Ballistic particle manufacturing
• Stream of material , such as plastic ,ceramic, metal or
wax ejected through small orifice at a surface
• Mechanism similar to inkjet mechanism ( piezo-electric
pump)
• Operation repeats similar to other process to form a part
with layers of wax deposited on top of each other
• Ink jet heat guided by three-axis robot
Ballistic Particle Manufacturing

18. 3-D Printing process
Similar to ballistic particle manufacturing
Fig:Three dimensional printing process

19. • Print head deposits an inorganic binder material
• Binder directed onto a layer of ceramic metal powder
• A piston supporting the powder bed is lower incrementally with
each step a layer is deposited and unified by binder
• Commonly used materials – Aluminum oxide, silicon carbide,silica
and zirconium.
• Common part produced by 3-D printing is a ceramic casting shall
• Curing around 150 C – 300 F
• Firing – 1000 C – 1500 C
3-D Printing process

20. Laminated object manufacturing (LOM )
• Laminated implies laying down of layers which are adhesively
bonded to one another
• Uses layer of paper or plastic sheets with heat activated glue
on one side of the product parts
• Excess material to be removed manually
• Simplified by preparing the laser to burn perforations in cross-
sectional pattern
• LOM uses sheets as thin as 0.05mm
• Compressed paper has appearance and strength of soft wood ,
and often mistaken for elaborate wood carvings.

21. Laminated Object Material (LOM)
Fig : (a) Laminated object-manufacturing process (b)Crankshaft-part example made by LOM

22. Virtual prototyping
• Virtual prototyping (modeling and simulation
of all aspects of a prototype, i.e. mechanical
design, kinematics, dynamics, and controls
accompanied by a realistic visualization).
• Realizing the best design in the shortest lead-
time of complex products/processes
• Allows the exotic, unconventional designs be
prototyped, rapidly and cost-effectively

23. Applications of Rapid Prototyping
• Production of individual parts
• Production of tooling by Rapid Prototyping (Rapid Tooling)
Fig: Manufacturing steps for investment casting that uses rapid prototyped wax parts as blanks.

24. Rapid Tooling
The term Rapid Tooling (RT) is typically used to describe a process which
either uses a Rapid Prototyping (RP) model as a pattern to create a mold
quickly or uses the Rapid Prototyping process directly to fabricate a tool
for a limited volume of prototypes .
a)Tooling time is much shorter than for a conventional tool. Typically, time to
first articles is below one-fifth that of conventional tooling.
b) Tooling cost is much less than for a conventional tool. Cost can be below
five percent of conventional tooling cost.
c) Tool life is considerably less than for a conventional tool.
d) Tolerances are wider than for a conventional tool.

25. Rapid Tooling
Fig: Manufacturing steps in sand casting that causes that uses rapid-prototyped patterns

26. Rapid Tooling
Fig: Manufacturing steps in sand casting that causes that uses rapid-prototyped patterns

27. THE END