High-speed machining of additively manufactured Inconel 718 using hybrid cryogenic cooling methods

Although additive manufacturing technologies offer manufacturing highly complex parts, the manufactured parts generally have poor surface quality. Owing to low machinability of hard-to-cut additively manufactured parts, a synergistic approach involving advantages of additive manufacturing and machining processes is needed. This study investigates high-speed machining of additively manufactured nickel alloys using hybrid cryogenic cooling methods. For the first time, a comprehensive study has been presented to compare the synergistic effect of hybrid cooling and lubrication strategies in high-speed milling of additively manufactured parts produced with powder bed fusion and directed energy deposition. The results indicate strong dependency of machinability on additive manufacturing methods and post-treatment strategy used. Hybrid methods make high-speed machining of additively manufactured parts possible, resulting in longer tool life and better surface finish. The cooling plays more significant role on tool life than lubrication. However, it was found that the hybrid cooling methods balanced heat removal and lubrication effects.

尽管增材制造（additive manufacturing）技术可制备复杂度极高的零件，但所获零件通常表面质量欠佳。由于增材制造的难加工构件切削加工性较差，因此亟需融合增材制造与切削加工工艺优势的协同解决方案。本研究针对采用复合低温冷却工艺的增材制造镍合金高速加工展开探究。本次研究首次系统性对比了针对粉末床熔融（powder bed fusion）与定向能量沉积（directed energy deposition）工艺制备的增材制造零件开展高速铣削时，复合冷却与润滑策略的协同效应。结果表明，零件的切削加工性与增材制造方法及后处理策略存在显著相关性。复合冷却工艺可实现增材制造零件的高速加工，有效延长刀具寿命并提升表面光洁度。相较于润滑，冷却环节对刀具寿命的影响更为显著，但研究发现复合冷却工艺可实现排热与润滑效果的平衡。