全密度功能性复杂金属零件的激光直接快速制造

摘要

It is very difficult to rapidly and directly manufacture functional metal part with complex structure and full density (FMPCD) . In this study, the method of rapid manufacturing FMPCD by selective laser melting(SLM) was discussed, and the problem of ensuring synchronously part density and precision during SLM process was analyzed in detail combined with some SLM experiments. The results show that in order to rapidly manufacture FMPCD by SLM, it is necessary to reduce the effects of balling, spattering and air holes on part density and precision; Balling and air holes can be avoided by maintaining enough re-melting amount of upper solidified layer which can be got through use of enough thin powder layer thickness and careful adjustment of other processing parameters under good antioxidant gas protection, and the bad effects of spattering on part quality can be weakened by proper scanning. Using this processing method, a complex-structure 316L stainless steel impeller with relative density of 99. 8%, hardness of HB192, size accuracy of ±0. 1 mm and surface roughness about 40 μm which is applicable after simple polishing was made successfully.%针对具有复杂结构的全密度功能性金属零件快速制造难题,探讨了该类零件的选区激光熔化直接快速制造方法,并结合实验,重点对同步保证选区激光熔化快速制造金属零件成型密度及精度的工艺进行了研究.结果表明:同步消除球化、飞溅及气孔对成型件致密性及精度的影响是实现选区激光熔化快速制造全密度功能性复杂金属零件的难点及关键；在维持良好的抗氧化气氛条件下,可采用尽可能薄的铺粉厚度及恰当调节其它成型参数的方法,以保证对上一层有足够的重熔量来消除球化及气孔现象；同时,采用合适的扫描策略,可弱化飞溅对成型质量的影响来解决工艺难题.采用该工艺方案可快速制造全密度功能性复杂金属零件,所成型的316L不锈钢叶轮零件相对密度为99.8％,硬度为HB192,表面粗糙度约为40 μm,尺寸精度在±0.1mm以内,稍经打磨后即可投入使用.