Process planning method for mask projection micro-stereolithography

Purpose - Mask projection micro-stereolithography (MP mu SLA) is an additive manufacturing process capable for fabricating true three-dimensional microparts and hence, holds promise as a potential 3D MEMS fabrication process. With only a few MP mu SLA systems developed and studied so far, the research in this field is inchoate and experimental in nature. In order to employ the MP mu SLA technology for microfabrication, it is necessary to model its part building process and formulate a process planning method to cure dimensionally accurate microparts. The purpose of this paper is to formulate a process planning method for curing dimensionally accurate layers. Design/methodology/approach - A MP mu SLA system is designed and assembled. The process of curing a single layer in resin using this system is modeled as the layer cure model. The layer cure model is validated by curing test layers. This model is used to formulate a process planning method to cure dimensionally accurate layers. The process planning method is tested by conducting a case study. Findings - The layer cure model is found to be valid within 3 percent for most of the features and within 10 percent for very small features (< 250 mu m). The paper shows that ray tracing can be effectively used to model the process of irradiation of the resin surface in a MP mu SLA system. Research limitations/implications - The process planning method is applicable only to those imaging systems, which are aberration limited as opposed to diffraction limited. The dimensional errors in the lateral dimensions of single layers cured by MP mu SLA have been modeled, but not the vertical errors in 3D parts. Originality/value - In this paper, a process planning method for MP mu SLA has been presented for the first time.