LASER SINTERING

INTRODUCTION

Direct metal laser sintering (DMLS) or Selective Laser Sintering(SLS) is an additive metal fabrication process. The technology fuses metal powder into a solid part by melting it locally using the focused laser beam. This process allows for highly complex geometries to be created directly from the 3D CAD data, fully automatically, in hours.

Rapid Prototyping• Rapid Prototyping (RP) can be defined as

a group of techniques used to quickly fabricate a scale model of a part or assembly using three dimensional computer aided design (CAD) data.

•

• SLS is a example for rapid prototyping

WHY RAPID PROTOTYPING NECESSARY?

•To decrease development time.

•To decrease costly mistakes

•Decreasing delivery time.

•To minimize sustaining engineering changes.

•Increase product complexity.

HOW IT WORKS

The SLS technology uses a C02 laser to sinter (fuse) a Variety of thermoplastic and metal powders to "grow" 3D objects layer-by-layer from 3D electronic data

The Solid Models as a: (a) Solid Model, (b) an STL file, and (c) in Sliced Layers.

Post-processingPost-processing

• Removal of part from platform

• Removal of supports from part

• Cleaning of part (wiping, rinsing, ... )

• Finishing part (curing, sanding, polishing, … )

THE MATERIAL

• The polyamide material allows the production of fully functional prototypes with high mechanical properties

• Glass powder and polyamide mixture

• Currently available alloys used in the process include stainless steel, cobalt Chromium, and titanium .

• Theoretically, almost any alloy metal can be used in this process.

ADVANTAGES OF SLS

• Wide variety of powders can use for this process.

• The physical process can be full melting, partial melting and depending on the material, up to 100% density can be achieved with material properties.

• SLS technology is in wide use around the world due to its ability to easily make very complex geometries directly from digital CAD data.

• It offers the key advantage of making functional parts in essentially final materials.

• The cost of an SLS part depends on

its volume Or in other words, the cost

is defined by the amount of powder it

takes to build it and not by an initial

investment in an injection moulding

tool

LIMITATIONS OF SLS• Surface finish

• SLS is prone to residual stresses that are caused by long term curing and environmental stresses

• The aspects of size

• Small error in z axis may lead to large error

APPLICATIONS

• Medical field

• Heat exchanger parts

• Space applications

• Lighting elements & products that require high thermal loads

Example of SLS Part (Drill)

Some SLS parts

CONCLUSION

Selective laser sintering provides exact representations of complex designs in just days. This means that without delay, you receive a superior design communication

tool. Using the physical prototype, you can detect errors early and correct them before

it's too late. It all adds up to hitting aggressive deadlines critical to time-to-

market reductions

REFERENCE

www.howstuffworks.com

K. Murali e t al. / Journal of Materials Processing Technology 136 (2003)

179-185

Laser sintering, J. Mater. Process. Technol. 111 (2001)210-21

www.acceIeratedtechnologies.com

THANKS