一种低功率实现高表面质量的细丝增材制造试验研究

针对在轨制造功率约束与金属增材成形高能量输入的矛盾问题，提出一种激光焦耳复合热源金属细丝增材制造工艺，激光功率仅约50 W，成功制造了宽高比高达40的薄壁结构，使用焦耳热加热丝材可以大大减少激光的功率，从而控制总的热输入，并对成形过程进行有效的热量管理，引入热阻概念进行递变参数优化的方法，有效减小了增材制造特有的台阶效应，成形件表面质量好，表面粗糙度Ra小于5 μm，优于激光选区熔融（Selective laser melting，SLM）工艺，同时，成形件无气孔和裂纹等缺陷，成形件的抗拉强度、致密度以及硬度分布等性能指标，也很接近制造原材料。结果表明，该激光焦耳细丝沉积（Laser Joule fine wire deposition，LJ-FWD）工艺，可以成为高表面质量零件增材制造的一个有吸引力方案，特别适合应用于太空在轨增材制造的快速成形。

Experimental Research of High-finish-surface AM Using Fine Wire Feed Deposition Process

Aiming at the contradiction between the power constraint of on-orbit manufacturing and the high energy input of metal additive manufacturing, a fine wire feeding AM technique based on laser Joule metal compound heat source is presented, which produces thin-wall structures of height-to-width ratio up to 40,using Joule heat to heat the wire can greatly reduce the laser power, so as to control the total heat input and effectively manage the heat in the process, and the concept of thermal resistance was introduced to optimize the variable parameters. The core forming power is only about 50 W. This method can greatly reduce the step effect in AM, resulting in roughness less than 5 mm, much better than that of selective laser melting (SLM). The sample had no defects such as pores and cracks, and the tensile strength, density and hardness distribution of the formed parts are also very close to the raw materials. The results show that the laser Joule fine wire deposition (LJ-FWD) process is a very attractive scheme in metal AM of high surface quality parts, in particular, will find application in rapid prototyping for on-orbit AM in outer space.