INTRODUCTION

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. What is commonly considered to be the first RP technique, selective laser sintering was patented by CARL DECKARD A UNIVERSITY OF TEXAS GRADUATE STUDENT. The company was founded in 1989, and since then, a number of different RP techniques have become available. Rapid Prototyping has also been referred to as solid free-form manufacturing; computer automated manufacturing, and layered manufacturing. RP has obvious use as a vehicle for visualization. In addition, RP models can be used for testing, such as when an airfoil shape is put into a wind tunnel. RP models can be used to create male models for tooling, such as silicone rubber molds and investment casts. In some cases, the RP part can be the final part, but typically the RP material is not strong or accurate enough. When the RP material is suitable, highly convoluted shapes (including parts nested within parts) can be produced because of the nature of RP.There is a multitude of experimental RP methodologies either in development or used by small groups of individuals.




WHY RAPID PROTOTYPING NECESSARY?

The reasons of Rapid Prototyping are
" To increase effective communication.
" To decrease development time.
" To decrease costly mistakes
" To minimize sustaining engineering changes.
" To extend product lifetime by adding necessary features and eliminating redundant features early in the design.

Rapid Prototyping decreases development time by allowing corrections to a product to be made early in the process. By giving engineering, manufacturing, marketing, and purchasing a look at the product early in the design process, mistakes can be corrected and changes can be made while they are still inexpensive. The trends in manufacturing industries continue to emphasize the following

" Increasing number of variants of products.
" Increasing product complexity.
" Decreasing product lifetime before obsolescence.
" Decreasing delivery time.
Rapid Prototyping improves product development by enabling better communication in a concurrent engineering environment.


HIGH LIGHTS OF SLS

" It is patented in 1989.

" Considerably stronger than stereo lithography.

" Laser beam selectively fuses powder materials; nylon, elastomers and so on metals.

" Process is simple.

" There is no milling or masking steps required.

" Powdering, porous surface unless sealant is used. Sealant also strengthens the part.

" Uncured materials are easily removed after a build by brushing of.