The aim of this research is to analyze the influence of shrinkage behavior on the deformation of forming parts in mask projection stereolithography. A mask projection stereolithography machine based on DLP( digital light procession) technology was designed, and the shrinkage of photosensitive resin during light-cured process was analyzed. The shrinkage behavior of resin in different exposure situations, free-surface and constrain-surface, and also in secondary curing process was studied. The result shows that in free-surface, the shrinkage of B5B type resin is proportional to the exposure time, eventually it stabilizes at around 4%. When it is in constrain-surface, the overflowed light curing effect leads to shrinkage which decreases with exposure time increased, and the shrinkage generated in the secondary curing process accounts for 40% ～50% of total.%为了研究面曝光固化过程中树脂收缩行为对成型零件变形的影响,设计并制作了基于DLP ( digital light procession)技术的面曝光固化快速成型机,分析了光固化过程中树脂收缩的原因. 对树脂在自由液面和约束液面2种曝光情况下的收缩行为进行实验,同时将固化成型件进行二次固化. 结果表明:自由液面曝光时, B5 B型树脂的收缩量与曝光时间成正比,最终稳定在4%左右,而在约束液面情况下由于溢出光固化效应导致收缩量随曝光时间增加而减小. 二次固化过程中仍会产生收缩,收缩量占收缩总量的40%～50%.
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