基于数字微反射镜器件的快速成形系统

Novel Stereolithography System Employing Digital Micro-Mirror Device

为实现微小零件高精度低成本快速制作,构建了新型面曝光快速成形试验系统。该系统由视图发生器、精密升降工作台及控制系统构成。利用视图发生器生成的零件截面图形作为动态掩模,对光敏树脂整层曝光固化,实现微小三维零件的制作。对视图平面紫外光强分布进行了研究,建立了光强分布关于被测点位置及视图灰度的关系模型,利用该模型,实现了视图平面紫外光强分布的均匀化,紫外光强的最大与最小值之差达到0.4μW/cm2。利用该快速成形系统,制作了具有复杂微小特征的三维零件。测试件的测量和分析结果表明,误差在±0.06 mm范围内尺寸数量占所有测量尺寸的72.2%。与扫描式光固化激光快速成形系统相比,该系统成本低,制作时间短。

To fabricate small objects with high accuracy and low cost,an integral stereolithography（SL） system has been developed,and the system consists of dynamic pattern generator,recoating system and control system.Photo-sensitive resin is solidified with image mask produced by dynamic pattern generator,and then small objects can be fabricated.Ultraviolet（UV） light intensity distribution in the imaging plane is investigated,and the relationship of UV light intensity with position in the imaging plane and gray-scale of pattern is established with least squares method.Uniformity UV light intensity distribution is obtained by controlling the gray-scale value at different positions in the imaging plane according to the relationship,and the difference between maximum and minimum value of UV light intensity is 0.4 μW/cm2.Small objects with microstructures are built with the SL system.A test part was designed,and the results of accuracy testing and statistical analysis demonstrate that the dimensions with error within ±0.06 mm are 72.22% in all testing dimensions.The notable characteristic of the novel SL system is that the new SL system can fabricate micro-structures with high-resolution at low cost.