激光选区熔化成型过程的粉末粘附问题分析

Analysis on Powder Adhesion Problems in Selective Laser Melting Forming Process

激光选区熔化金属粉末形成金属零件的过程中存在粉末粘附现象,对零件的成型精度影响很大。为此,从粉末粘附现象的成因、粘附颗粒的分类及粘附颗粒对成型精度的影响机理等方面研究了粉末粘附现象。归纳出了粉末粘附对不同类型成型面的影响。结合成型工艺试验分析,从扫描路径规划及材料摄入能量调配方面提出了弱化粉末粘附现象对成型精度影响的方法,并进行了试验验证。结果表明:通过一种多重勾边+内缩填充扫描策略,并结合合适的扫描速度,可弱化粉末粘附对零件侧壁表面精度的影响,能获得Rz26.9μm的侧壁表面粗糙度。

Powder adhesion phenomenon often occurs during the process of forming a metal part by selective laser melting of metal powder, which can cause great impact on the forming precision of SLM parts. Therefore, the powder adhesion phenomenon was studied from some aspects such as the reasons for forming this phenomenon, adhesive powder types and their influence mechanism on the molding precision. The effects of powder adhesion on the different types of molding surface were summarized. Combined with some processing experiments, a method based on scanning path planning and regulation of energy intake of material for weakening the influence of powder adhesion phenomenon on the molding precision was proposed, and then the method was verified by SLM experiment. The results show that by scanning strategy of multiple edges marking plus shrinkage filling and combined with the use of faster scanning speed, the effects of powder adhesion on the surface precision of the side wall of the part can be greatly weaken, and then, the surface roughness degree of side wall of the part can reach Rz26.9 μm.