工艺参数对选择性激光烧结PS/SBS/纳米CaCO3制件弯曲强度影响

针对聚苯乙烯(PS)粉末选择性激光烧结(SLS)成型件强度较低的问题,采用机械混合法制备了PS/苯乙烯–丁二烯–苯乙烯嵌段共聚物(SBS)/纳米CaCO₃复合粉末,通过单因素实验分析了SLS工艺参数对成型件弯曲强度的影响,并通过正交试验和极差分析获得了最优工艺参数组合。实验结果表明,烧结件的弯曲强度随着激光功率的增大而升高,随着扫描速度、扫描间距和分层厚度的增大而降低;激光功率对PS/SBS/纳米CaCO₃复合粉末烧结件弯曲强度的影响最大,分层厚度对弯曲强度的影响最小,扫描速度和扫描间距的影响介于两者之间;最佳工艺参数组合为:激光功率27 W,扫描速度1300 mm/s,扫描间距0.24 mm,单层厚度0.22 mm。在此工艺参数组合下PS/SBS/纳米CaCO₃复合粉末烧结件的弯曲强度为13.38 MPa;改性纳米CaCO₃与PS和SBS的相容性较好,能有效起到增强的作用。

Effects of Process Parameters on Bending Strength of PS/SBS/Nano CaCO3 Parts Made by Selective Laser Sintering

In order to solve the problem of low strength of polystyrene(PS)powders forming parts based on selective laser sintering(SLS),PS/styrene butadiene styrene block copolymer(SBS)/nano CaCO₃ composite powders were prepared by mechanical mixing method.The influences of SLS process parameters on the bending strength of the parts were analysed by single factor experiment.The optimal combination of process parameters was obtained by orthogonal test and range analysis.The experimental results show that the bending strength of sintered parts increases with the increase of laser power,and decreases with the increase of scanning speed,scanning distance and delamination thickness.The influence of laser power on the bending strength of PS/SBS/nano CaCO₃ composite powder formed parts is the largest,the influence of delamination thickness on the bending strength is the smallest,and the influences of scanning speed and scanning distance are between the two.The optimal process parameters are:laser power 27 W,scanning speed 1300 mm/s,scanning spacing 0.24 mm,single layer thickness 0.22 mm.The results show that the bending strength of the sintered parts is 13.38 MPa under the combination of the optimal process parameters.The modified nano CaCO₃ have good compatibility with PS and SBS,which can effectively play a role in strengthening.