复合光斑选区熔化成形技术研究

Study on Selective Laser Melting Technology of Composite Spot

激光选区熔化技术由于是以高能激光束对金属粉末层进行选择性快速扫描,扫描过程中形成不均匀的温度场而极易产生应力,残余应力的存在易引起裂纹、变形等缺陷。采用双激光光斑复合辅以成形缸加热保温的方法,成功研制能在成形过程中提供较均匀温度场的激光选择性熔化成形装置,并进行大量工艺试验。结果表明:在成形缸进行加热保温的条件下,采用双激光复合光斑选择性熔化H13金属粉末,粉末熔道更饱满、连续,相邻熔道的浸润和搭接更均匀,成形的零件无裂纹缺陷。

Laser selective melting technology is a selective and rapid scanning of metal powder layer with high energy laser beam. During the scanning process,uneven temperature field is formed and stress easily occurs,so the existence of residual stress can easily cause cracks and deformation. A laser selective melting forming device which can provide uniform temperature field in the forming process was successfully developed by using the method of double laser spot composite and steam tracing of the forming cylinder,then a large number of technological experiments were carried out. The results show that using the double laser combined spot selectively melts the H13 metal powder under the condition of heating and insulation of the forming cylinder,the channel of powder melt could be more plump and continuous,and infiltration and lapping of the adjacent melt channel could be more even,forming a part without crack defects.