1. RAPID PROTOTYPING (RP)
CAD/CAM/CAE

2. SELECTIVE LASER SINTERING (SLS)
Selective Laser Sintering (SLS, registered trademark by DTM™ of Austin, Texas, USA) is a process that was patented in 1989 by Carl Deckard, a University of Texas graduate student.
Its chief advantages over Stereolithography (SLA) revolve around material properties.
Many varying materials are possible and these materials can approximate the properties of thermoplastics such as polycarbonate, nylon, or glass-filled nylon, polystyrene, polycarbonate or polyamide etc.

3. SELECTIVE LASER SINTERING (SLS)

4. SELECTIVE LASER SINTERING (SLS)
In this method metal powder particles are joined together to form a solid component by using a computer controlled laser beam.
This high powered beam is focused on a layer of powder that traces and sinter the defined shape in to a solid pattern.
The table is then lowered and another layer of powder is deposited which gets fused to the earlier layer. The cycle is repeated till the model is built up.
The process can be used for good range of material like polymers, wax, metal and ceramic and does not requires post curing (except ceramic).

5. SELECTIVE LASER SINTERING (SLS)
SLS machine consists of two powder magazines on either side of the work area.
The leveling roller moves powder over from one magazine, crossing over the work area to the other magazine.
The laser then traces out the layer.
The work platform moves down by the thickness of one layer and the roller then moves in the opposite direction.
The process repeats until the part is complete.

6. SELECTIVE LASER SINTERING (SLS)

7. SELECTIVE LASER SINTERING (SLS)
Before starting CO2 laser scanning for sintering of a slice the temperature of the entire bed is raised just below its melting point by infrared heating in order to minimize thermal distortion (curling) and facilitate fusion to the previous layer.
The laser is modulated in such away that only those grains, which are in direct contact with the beam, are affected.
Once laser scanning cures a slice, bed is lowered and powder feed chamber is raised so that a covering of powder can be spread evenly over the build area by counter rotating roller.

8. SELECTIVE LASER SINTERING (SLS)
Advantages
No post-curing of the parts is needed, except for ceramic
Parts can often be built without additional support structures
Parts in a range of materials can be obtained directly.
Disadvantages
Surfaces of the parts are porous
Surface finish can be poor
Machines take long time to heat up and cool down;
Parts can warp significantly.

9. SELECTIVE LASER SINTERING (SLS)
Summary of the SLS process
Materials available : Carbon steel with polymer binder, nylon, polystyrene, polycarbonate, ceramics coated with binder, zirconium sand coated with polymer, flexible elastomer
Layer thickness : mm
Tooling methods available: Investment casting, vacuum casting, direct injection mould tooling

10. SELECTIVE LASER SINTERING (SLS)

11. SLA vs. SLS Principle of operation:
SLA: Laser beam scans and solidifies the layer of liquid resin
SLS: laser beam scans and sinters the layer of powered polymer
Material Properties:
SLA: Process is limited to photosensitive resins which are typically brittle.
The liquid resin is typically thermosetting plastic
SLS: process can utilize polymer powders that, when sintered, approximate thermoplastics quite well.

12. SLA vs. SLS Surface Finish:
SLS: Surface is powdery, like the base material whose particles are fused together without complete melting.
SLA: Smoother surface of an SLA part typically wins over SLS when an appearance model is desired.
In addition, if the temperature of uncured SLS powder gets too high, excess fused material can collect on the part surface. This can be difficult to control since there are so many variables in the SLS process.
In general, SLA is a better process where fine, accurate detail is required.
However, a varnish-like coating can be applied to SLS parts to seal and strengthen them.

13. SLA vs. SLS Dimensional Accuracy:
SLA: More accurate immediately after completion of the model
SLS is less prone to residual stresses that are caused by long-term curing and environmental stresses.
Both SLS and SLA suffer from inaccuracy in the z-direction, but SLS is less predictable because of the variety of materials and process parameters.
The temperature dependence of the SLS process can sometimes result in excess material fusing to the surface of the model, and the thicker layers and variation of the process can result in more z inaccuracy.
SLA parts suffer from the "trapped volume" problem in which cups in the structure that hold fluid cause inaccuracies.
SLS parts do not have this problem.

14. SLA vs. SLS Support Structures:
SLA: Parts typically need support structures during the build.
SLS: Parts, because of the supporting powder, sometimes do not need any support, but this depends upon part configuration.
Marks left after removal of support structure cause dimensional inaccuracies and cosmetic marks. (SLA)
Machining Properties:
In general, SLA materials are brittle and difficult to machine.
SLS thermoplastic-like materials are easily machined.

15. SLA vs. SLS Post Processing: SLA parts typically need post processing.
Cleaning
Removal of support
Post curing in the form of Hardening
SLS parts needs no post processing
Size:
SLS and SLA parts can be made the same size, but if sectioning of a part is required, SLS parts are easier to bond.

16. LAMINATED OBJECT MANUFACTURING
Highlights of Laminated Object Manufacturing
Layers of glue-backed paper form the model.
Low cost: Raw material is readily available.
Large parts: Because there is no chemical reaction involved, parts can be made quite large.
Accuracy in z is less than that for SLA and SLS.
Outside of model, cross-hatching removes material
Models should be sealed in order to prohibit moisture.
Before sealing, models have a wood-like texture.
Not as prevalent as SLA and SLS

17. LAMINATED OBJECT MANUFACTURING
Laminated object manufacturing (LOM) is often described as turning paper back into wood (though non-paper material is also available for the technique), as LOM is often used to make wooden patterns for sand casting.
These patterns are fairly durable, and therefore re-useable.
LOM is one of the cheapest RP technologies and is excellent for making large parts with moderate geometrical complexity.
Material is usually a paper sheet laminated with adhesive on one side, but plastic and metal laminates are appearing.

18. LAMINATED OBJECT MANUFACTURING
Layer fabrication starts with sheet being adhered to substrate with the heated roller.
The laser then traces out the outline of the layer.
Non-part areas are cross-hatched to facilitate removal of waste material.
Once the laser cutting is complete, the platform moves down and out of the way so that fresh sheet material can be rolled into position.
Once new material is in position, the platform moves back up to one layer below its previous position.
The process can now be repeated.

19. LAMINATED OBJECT MANUFACTURING
A layer of material with an adhesive coating on one side is placed on a platform, adhesive side down.
A heated roller passes over the material and sticks the material to the platform.
A laser beam then traces the outline of one slice of the part, cutting through the layer of the material.
The laser beam then crosshatches the material that does not form part of the cross-section, again cutting through the layer.

20. LAMINATED OBJECT MANUFACTURING
The platform is then lowered one layer thickness, another layer of material is stuck onto the previous layer and the procedure is
repeated with the next cross-section slice of the part.
When all cross-section slices have been added, the solid block of material is removed from the platform.
The crosshatched areas of the block are then broken away to reveal the final part.

21. LAMINATED OBJECT MANUFACTURING

22. LAMINATED OBJECT MANUFACTURING

23. LAMINATED OBJECT MANUFACTURING
The excess material supports overhangs and other weak areas of the part during fabrication.
The cross-hatching facilitates removal of the excess material.
Once completed, the part has a wood-like texture composed of the paper layers.
Moisture can be absorbed by the paper, which tends to expand and compromise the dimensional stability.
Therefore, most models are sealed with a paint or lacquer to block moisture ingress (entrance) .
The LOM developer continues to improve the process with sheets of stronger materials such as plastic and metal.
Now available are sheets of powder metal (bound with adhesive) that can produce a "green" part.
The part is then heat treated to sinter the material to its final state.

24. LAMINATED OBJECT MANUFACTURING
Advantages
Wooden parts can be sanded, drilled and tapped; and
Large parts can be made quickly and relatively cheaply.
Disadvantages
Wooden parts with thin cross-section often have poor strength;
Wooden parts absorb moisture unless the surface is treated;
Surface finish before post-processing is poor compared to some other RP techniques; and
Breaking out of parts can be difficult.

25. LAMINATED OBJECT MANUFACTURING

26. RAPID PROTOTYPING (RP)
Highlights of Fused Deposition Modeling
Standard engineering thermoplastics, such as ABS, can be used to produce structurally functional models.
Two build materials can be used, and latticework interiors are an option.
Parts up to 600 × 600 × 500 mm (24 × 24 × 20 inches) can be produced.
Filament of heated thermoplastic polymer is squeezed out like toothpaste from a tube.
Thermoplastic is cooled rapidly since the platform is maintained at a lower temperature.
Milling step not included and layer deposition is sometimes non-uniform so "plane" can become skewed.
Not as prevalent as SLA and SLS, but gaining ground because of the desirable material properties.

27. RAPID PROTOTYPING (RP)
Fused Deposition Modeling
Stratasys of Eden Prairie, MN makes Fused Deposition Modeling (FDM) machines.
The FDM process was developed by Scott Crump in 1988.
The fundamental process involves heating a filament of thermoplastic polymer and squeezing it out like toothpaste from a tube to form the RP layers.
The machines range from fast concept modelers to slower, high-precision machines.
The materials include polyester, ABS, elastomers, and investment casting wax. The overall arrangement is illustrated below:

28. RAPID PROTOTYPING (RP)
Applications of Rapid Prototyping
1. RAPID TOOLING
Patterns for Sand Casting
Patterns for Investment Casting
Pattern for Injection moldings
2. RAPID MANUFACTURING
Short productions runs
Custom made parts
On-Demand Manufacturing
Manufacturing of very complex shapes

29. RAPID PROTOTYPING (RP)
Applications of Rapid Prototyping
3. AEROSPACE & MARINE
Wind tunnel models
Functional prototypes
Boeing’s On-Demand-Manufacturing
4. AUTOMOTIVE RP SERVICES
Needed from concept to production level
Reduced time to market
Functional testing
Dies & Molds

30. RAPID PROTOTYPING (RP)
Applications of Rapid Prototyping
5. BIOMEDICAL APPLICATIONS - I
Prosthetic parts
Presurgical planning models
Use of data from MRI and CT scan to build 3D parts
3D visualization for education and training
5. BIOMEDICAL APPLICATIONS - II
Customized surgical implants
Mechanical bone replicas
Anthropology
Forensics

31. RAPID PROTOTYPING (RP)
Applications of Rapid Prototyping
6. ARCHITECTURE
3D visualization of design space
Iterations of shape
Sectioned models
7. FASHION & JEWELRY
Shoe Design
Jewelry
Pattern for lost wax
Other castings
8. SCULPTURES
3D scanning
Layered fabrication
Replicas
Original work