Selective laser sintering and 3D printing

Selective laser sintering

 In the Selective laser Sintering (SLS) process originally developed at the University of Texas at Austin, modulated laser beam follows the shape of a slice of a CAD generated object; it traces the object across a bin of special heat fusible  powders, heating the particles So they fuse or sinter together. In SLS, a layer of powdered material is spread out and levelled in the plane where the layer is to be formed. A CO2 lasers then selectively traces the layers to fuse those areas defined by the geometric of the cross sectional along with fusing to the bottom layer. The powders can be joined by melting or surface bonding.  The unfused material remains in place as the support structure. After the initial layer is formed, the power is reapplied, and the laser processes the next layer. some of the materials used are plastics, waxes and low melting temperature metal alloys. Because of the use of metal powders, this process is greatly used in application such as direct tooling application for investment and Die Casting applications.

selective laser sintering

 A  large variety of build materials are available for the SLS systems. Plastic materials provide increased stiffness, heat resistance and mechanical integrity to make them perfect full functioning prototypes. The materials will have properties similar to ABS and polypropylene such that the parts made with them will have properties that are similar to injection moulding. Some materials also have flexibility similar to rubber so that part's requiring flexibility can also be made with these materials. Metallic materials have properties that are sufficient to use them for making direct metallic parts as well as tool making. They provide good surface finish and excellent machinability.

Large ranges of machines are available with various build volumes. These provide large build area so that large parts or tooling inserts can be easily produced.

3D Printing

3D printing : Originally developed at the  Massachusetts Institute of Technology( MIT) in 1993, 3D printing can be compared to SLS; the difference is that instead of a laser beam, liquid binder is applied to bond the powder particles. A 3D printer is operated in the following sequence. The printer spreads  a layer of powder from the feed box to cover the surface of the build platform and then  prints the Binder solution onto the loose powder, forming the first cross section of the part where the Binder is printed, the powder's particles are glued together. The remaining powder is loose and supports the  part as it is being printed. when the cross section is completed, the build platform is lowered slightly, and a new layer of powder is spread over its surface. The process is repeated until the whole model is completed. The build platform is raised and the loose powder is removed revealing the completed part.

3D printing

 Dispensing the glue is similar to an inkjet printer; it is possible to print in multicolour to make the build part to have the requisite colours to add for better visualisation. This is a low cost process compared to the other processes considered so far. However, these parts to not have the necessary mechanical strength, and are used only for the visualisation purpose.

If u like please share to your friends as a helping hands.Any problem do comment..