The document discusses selective laser sintering (SLS), a rapid prototyping technology that uses a laser to fuse powdered material into a 3D object. SLS works by scanning cross-sections from a CAD file onto a powder bed, fusing the material with a laser. This process is repeated layer-by-layer until the object is complete. SLS offers advantages like high accuracy, flexibility in materials used, and the ability to produce complex parts without supports. Some disadvantages are higher costs and potentially weaker parts compared to traditional manufacturing. The document provides details on the SLS process, parameters, materials used, defects that can occur, and applications.

1. A
Presentation on
SELECTIVE LASER SINTERING :A RAPID
PROTOTYPING TECHNOLOGY
Presented by:
SURAJBHAN SINGH
B.E.FINAL YEAR (14PIE79529)
PRODUCTION AND INDUSTRIAL ENGINEERING DEPT.
M.B.M. ENGINEERING COLLEGE, jodhpur

2. Introduction
(Selective laser sintering)SLS is a rapid prototyping (RP) technology that able
to produce physical model in a layer by layer manner directly from their CAD
models without any tools, dies and fixtures.
The build media for SLS comes in powder form, which is fused together by a
powerful carbon dioxide laser to form the final product.
 RP is capable to fabricate parts quickly with too complex shape easily as
compared to traditional manufacturing technology. RP helps in earlier
detection and reduction of design errors.
The SLS process begins, like most other RP processes, with the standard .STL
CAD file format, which is exported now by most 3D CAD packages.
 SLS was developed and patented by Dr. Carl Deckard and academic adviser,
Dr. Joe Beaman at the University of Texas at Austin in the mid-1980s.

3. Highlight of SLS
Process is simple. There is no milling,broaching, turning etc steps are
required .
Powdering,porous surface unless sealant is used.
Recommended for chemically resistant parts.
High strength and stiffness.
Fully functional and high quality plastic parts.
 excellent long–term stability.
Use in medical applications.

4. Technology
An additive manufacturing layer technology, SLS involves the use of a high
power laser (carbon dioxide laser) to fuse small particles
of plastic, metal, ceramic, or glass powders into a mass that has a desired 3-
D shape.
The laser selectively fuses powdered material by scanning cross-sections
generated from a 3-D digital description of the part (from a CAD file or scan
data) on the surface of a powder bed. After each cross-section is scanned,
the powder bed is lowered by one layer thickness, a new layer of material is
applied on top, and the process is repeated until the part is completed.
Because finished part density depends on peak laser power, rather than
laser duration, a SLS machine typically uses a pulsed laser.
The SLS machine preheats the bulk powder material in the powder bed
somewhat below its melting point, to make it easier for the laser to raise
the temperature of the selected regions the rest of the way to the melting
point.

5. WORKING

6. Process parameter
 Powder related ( particle shape, size, material properties etc)
 Duration of pulse
 Overlap
 Scan (speed ,size, spacing)
 Power
 Dwell period
 Temperature
 Layer thickness

7. Materials
Thermoplastic powders(nylon ,glass filled nylon, polystyrene etc)
Metal powders
Ceramic powders
Glass powders

8. Defects
Bonus Z
Clumping
Curling, in-built curl
Growth
Cracking

9. Advantages and Disadvantages
Advantages
 Highly dimensional accuracy
 Capable of high detail and thin
walls
 Design changes and modification
can be easily
 Flexibility in selection of material
 Fabricate complex parts
 No need to create a structure to
support the part
 Parts do not require any post
curing
Disadvantages
 The price of machinery and
materials are expensive
 The surface is usually rougher than
machined surfaces
 Some materials are brittle
 Shrinking and warping in fabricated
parts because of thermal distortion
 During solidification, additional
powder may be hardened at the
border line
 The strength of RP-parts are weaker
in z-direction than in other

10. Application
3D printing in rapid prototyping
Parts for mechanical and thermal tests
Fabricate small complex plastic parts
Agricultural applications(greenhouse covering etc)
Fabricate electrical devices(resistors etc )
Aerospace and aviation industries
Automotive industry
Medical industry
Architecture

11. Conclusion
 It can be conclude that, among various techniques of rapid prototyping
selective laser sintering is the most flexible process that accommodates
large variety of material being processed
This technique have better control and superior qualities then it is used
for industrial applications

12. Thank you