Development of rapid prototyping system for ceramic shell mold of precision casting

Layer manufacturing (LM) is one of the most important techniques of rapid prototyping. Comparing with the machining, the main shortcomings of LM are the surface roughness of the work piece and time consuming. Many rapid prototyping techniques have been developed for many years, such as stereolithography apparatus (SLA), selective laser sintering (SLS) and laminated object manufacturing (LOM). The surface roughness and dimensional accuracy of the work piece still cannot conform to the requirements of the clients. The main reason is the "step effect" generated with layer stacking. This study develops an experimental system to achieve the layer thickness less than 25 /spl mu/m which is thinner than the existing apparatuses using processes mentioned above, and the surface finish less than 8 /spl mu/m. Besides, current study also investigates the feasibility of making ceramic shell mold via a new process, named ceramic laser sintering (CLS). Under the new process, the step effect can be minimized; the drying time is shortened dramatically and the production is speedy.