PS/化学气相沉积CF选区激光烧结多指标正交试验参数的优化

针对选择性激光烧结(SLS)工艺中聚苯乙烯(PS)粉末烧结件精度不高且强度不能满足实际需求的问题,将经过化学气相沉积法处理的碳纤维(CF)粉末、PS粉末、分散剂和抗静电剂进行机械混合,制备了PS/气相沉积CF复合粉末。以Z向尺寸相对误差、致密度和弯曲强度为实验指标,先采用极差分析法进行单个指标的优化,再利用综合平衡法对多指标正交试验进行整体参数优化分析。结果表明:复合粉末粒度主要分布在30.63~142.00μm;对于PS粉末烧结件,化学气相沉积CF粉末比普通的CF粉末具有更好的改善尺寸精度、填充和增强的效果;烧结件的最佳工艺参数组合为:预热温度为80℃,激光功率为27 W,扫描速度为1 800 mm/s和扫描间距为0.30 mm。此时烧结件的Z向尺寸相对误差为5.47%,致密度为0.626 g/cm3,弯曲强度为10.68 MPa。相比于纯PS粉末烧结件,分别提高了24.55%,30.42%,136.28%。

Parameters Optimization of Multi-index Orthogonal Test for PS/Chemical Vapor Deposited CF by SLS

Aiming at the problems that polystyrene (PS) powders sintered parts forming precision is not high and the strength can't meet actual needs in selective laser sintering (SLS) process,the carbon fiber (CF) powders treated by chemical vapor deposi-tion method,PS powders,dispersant and antistatic agent were mixed through mechanical method,the composite powder of PS/chemical vapor deposited CF powder was prepared. Considering the relative error in the Z direction,density and bending strength as experimental indexes. First,the method of range analysis was used to optimize single index,and then the comprehensive bal-ance method was used to optimize the multi-index orthogonal test. The result show that the particle size of the composite powders is mainly distributed in 30.63-142.00 μm. For PS powders sintered parts,the chemical vapor deposited CF powders have better effect on improving the dimensional accuracy,filling and strengthening effect than ordinary CF powders. The optimum combination of process parameters of SLS parts are preheating temperature 80℃,laser power 27 W,scanning speed 1800 mm/s and scanning interval 0.30 mm. At this point,the relative error in the Z direction of sintered parts is 5.47%,the density is 0.626 g/cm3,and the bending strength is 10.68 MPa,which is increased by 24.55%,30.42% and 136.28% respectively compared with pure PS sintered part.