1. 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. Additive Process 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

9. Additive: 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. Additive: 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

11. Additive: 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.

12. Selective laser sintering
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

13. Fig:The solid based curing process
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

14. 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

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

16. 3-D Printing process 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

17. 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.

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

19. 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

20. 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.