纯铜粘结剂喷射增材成形与烧结致密化机理

Mechanism of Pure Copper Binder Jetting Additive Forming and Sintering Densification

摘要:

粘结剂喷射增材制造技术打印过程与脱脂烧结工艺过程分步进行，可以实现高激光反射率高导热性的纯铜加工成形。对纯铜粘结剂喷射增材制造工艺参数进行了研究。包括铺粉层厚与喷墨密度对生坯成形性能的影响，烧结氛围（真空环境与氢气气氛）与烧结温度对零件烧结致密化过程的影响，结果表明，铺粉层厚75 μm，喷墨密度50%参数组合在保证生坯密度与压缩强度的前提下，具备高尺寸精度与高表面质量。氢气气氛烧结驱动力显著强于真空环境，氢气的引入可以有效还原表面氧化层。试样在1060 ℃时致密度为77.70%，碳残留物形成孔隙抑制烧结过程致密化，在1070 ℃时致密度为93.94%，试样严重变形，碳残留物挤压至表面。这为进一步优化纯铜粘结剂喷射增材制造工艺指明了方向。

Abstract:

The printing process and the debinding sintering process were carried out step by step to realize the pure copper processing with high laser reflectivity and high thermal conductivity. The process parameters of pure copper binder jetting additive manufacturing were studied. The effects of powder layer thickness and inkjet density on green parts forming performance were studied. At the same time, the effects of sintering atmosphere and sintering temperature on the densification process of the parts were studied. The results show that the combination of powder layer thickness of 75 μm and inkjet density of 50% can ensure the density and compression strength of green parts, resulting in high dimension precision and high surface quality. The driving force in hydrogen atmosphere is stronger than that in vacuum, and the surface oxide layer can be effectively reduced by the introduction of hydrogen. The compactness of sample treated at 1060 ℃ is 77.70%, the carbon residue forms pores to restrain the sintering process, and the compactness of sample treated at 1070 ℃ is 93.94%. It points out the direction for further optimizing the manufacturing process of binder jetting with pure copper.