PS/PMMA复合材料选区激光烧结成型收缩率

Shrinkage of PS/PMMA Composite by Selective Laser Sintering

针对选区激光烧结聚苯乙烯(PS)成型件收缩率大,精度差的问题,通过添加聚甲基丙烯酸甲酯(PMMA)粉末制备PS/PMMA复合材料来提高成型件精度。研究了预热温度、扫描速度、分层厚度和扫描间距对成型件尺寸收缩率的影响并进行了正交实验,应用信噪比对结果降噪处理后再进行极差分析,得到最优工艺参数组合;在最优工艺参数组合下重新烧结,利用修正系数补偿精度。结果表明:竖直方向收缩率变化幅度大于水平方向,扫描速度和分层厚度分别对水平方向与竖直方向收缩率影响最大;最优工艺参数组合为:预热温度100℃,扫描速度2 400mm/s,分层厚度0.27mm,扫描间距0.28mm;此时水平方向与竖直修正系数为1.0417和1.013 8,修正后水平方向收缩率与竖直方向收缩率分别为0.947%和1.105%。

Aiming at the problem of large shrinkage and poor precision of the selected laser-sintered polystyrene (PS) molded parts,the composite material of PS/PMMA was prepared by adding PMMA powder to improve the precision of the molded parts. The influence of thermal temperature,scanning speed,layer thickness and scanning pitch on the dimensional shrinkage of the molded part was studied and the orthogonal experiment was designed. The signal-to-noise ratio (SNR) was used to reduce the noise and then use the range analysis to obtain the optimal combination of process parameters. The model is modified by sintering experi- ment under the optimal combination of process parameters. The results show that the vertical direction shrinkage rate changes more than the horizontal direction,and the scanning speed and the layer thickness have the greatest influence on the horizontal and vertical shrinkage. The optimal process parameters are preheating temperature of 100℃ and scanning speed of 2 400 mm/s. The layer thick- ness is 0.27 mm and the scanning pitch is 0.28 mm;the horizontal direction and the vertical correction coefficient are 1.0417 and 1.013 8. The horizontal shrinkage and vertical shrinkage are 0.947% and 1.105% respectively.