Stereolithography with the ProJet® 7000 SLA from 3D Systems

Stereolithography prototypes made from special epoxy / acrylate resins are used to verify and optimize a design, for initial functional and assembly tests, for presentation and marketing purposes. Thanks to the high precision that can be achieved with the ^ProJet® 7000HD, typically 0.1%, and the good surface quality, which can be further improved by additional post-processing (polishing, coating), they are also used in particular as master models for a range of casting processes, such as vacuum casting, rapid tooling and metal casting.

As with all 3D printing processes, the starting point is an STL file that digitally describes the component and is converted into a large number of cross-sections (slices) of the component, typically 0.025 - 0.1 mm, using the manufacturer's special software. A computer-controlled laser beam is used to direct the layers onto the surface of the liquid photopolymer plastic, whereby the laser beam triggers a local chemical reaction (polymerization) and hardens the resin. The polymerization depth exceeds the selected layer thickness in order to ensure a good chemical bond between the layers. After each curing phase, the object, which is fixed on a vertically movable platform using supports, is lowered by one layer thickness and coated with a new layer of liquid resin, after which the SLA process begins with a new layer. Once the construction process is complete, the supports must be removed, the component is cleaned and post-cured using UV light and then further treated as required.