Editorial Feature

Rapid Prototyping - Laser Fusion and Selective Laser Sintering

In addition to quality and cost, time to market is becoming an increasingly important factor in a product's success.  A major contributor to product development cycles is the time needed to produce prototypes.  Further, in markets where customers are demanding individually tailored components, the cost and time to produce tools or moulds can be considerable. 

Rapid Prototyping (RP), also known as Solid Freeform Fabrication (SFF) processes help to overcome these problems In general the processes build complex shapes through additive processes, producing components without the use of tools.

Laser Fusion

The most advanced laser fusion technique is the commercial selective laser sintering (SLS).  In this process the feed stock is a thin layer of ceramic coated with a thermoplastic binder.   A laser beam scans the surface defining the regions to sinter, fusing the polymer and bonding the particles.  The remainder of the layer remains as a loose powder.  The layer is lowered and a further loose powder layer is applied.  The laser is then used to process the next layer, bonding it to the first layer.  The procedure is repeated until the green state component is produced. This can then be processed through traditional processes once the binder has been burnt out.  It is believed that any material that can be densified by traditional sintering techniques can be processed by SLS, for example Al2O3, SiC and Zr composites.

Schematic of a selective laser fusion setup.

Figure 1. Schematic of a selective laser fusion setup.

Selective Laser Sintering

Higher powered (>50W) lasers can be used to sinter powders directly without the need for a polymer binder.  Al2O3 - B2O3 composites and WC-Co powder mixtures have been made by this technique, but the density was only 70% theoretical and post treatment sintering was still needed.

Source: CERAM Research Ltd

For more information on this source please visit CERAM Research Ltd.

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