Build Chamber Volume
The most LS machines are developed and fabricated by EOS GmbH and 3D Systems, Inc. Both companies have several machine types in their portfolio. The build chamber volume depends on the size of the machine. The smallest LS machine has a chamber volume of 200x250x330 mm³ (x/y/z). Bigger parts can be build inside a chamber volume up to 550x550x750 mm³.
Build Time and Build-up Rate
The build time depends on the part size, its orientation inside the building chamber and the machine itself. Furthermore, machines usually offer different operating modes with different layer thicknesses and scanning parameters, which have big influences on the build-up rate as well. In most cases, it is possible to build parts with a speed of approximately 20 mm/h build height.
In general, plastic, metal and sand powders can be used in the LS process. For processable metal materials see the characteristics of “Selective Laser Melting”. The common plastic powders market is dominated by polyamide material, where PA12 is clearly more used than PA11. Variants of PA12 consist of blends with other types of materials. These materials are custom-made polymers that suit the industrial demand in different fields requiring specific properties, e.g. fire or acid resistance. High-performance polymers for the LS process, e.g. PEEK HP3 (based on Polyaryletherketone – PAEK), are suitable for applications that require excellent high temperature performance, wear and chemical resistance etc. Furthermore, materials on the basis of TPE or TPU are available for applications, where a flexible behavior of the material is required.
The parts cool down slowly due to the high temperatures during the production process and the low heat conductivity of the bulk powder. The remaining powder surrounding the models needs to be removed, which can be done in an unpacking station, where the powder can be sieved as well. The used powder will then be recycled by mixing it with virgin powder. To ensure a constant powder quality, methods to specify the powder age are required. The models, which still have loose adhered powder on their surfaces after unpacking, will be compressed air and glass bead blasted to get their final appearance.