StereoLithography 1993: QuickCast TM

Previously, StereoLithography (SL) generated solid patterns had limited success highly accurate shell investment casting applications. The majority of the failures involved the cracking of the ceramic investment casting shell. However, the recent invention of the QuickCast 'l'M build-style and the development of a new epoxy resin, XB 5170, led to an unprecedented level of success the burnout process of SL patterns from investment casting shells. Unlike conventional building techniques, QuickCast involves the building of SL patterns with essentially hollow structures. When the low viscosity liquid epoxy resin is drained from the interior of the pattern, voids are formed, allowing the cured resin to collapse inwards during the autoclave and burn-out stages. This effectively prevents the shells from cracking as the result of outward thermal expansion. 3D Systems formed QuickCast teams with three respected foundries to test shell investment casting using SL patterns. A test part having relatively complex geometries a Boeing 737 cargo door bracket) was selected. To date, this SL part has been successfully cast aluminum, titanium, beryllium-copper, and stainless steel, with RMS surface finish as low as 1 micrometer, without any subsequent finishing operations.