金属增材制造缺陷检测技术

金属增材制造过程中材料温度变化剧烈、行为复杂,特殊的工艺特点使零件中不可避免地出现各类缺陷,包括表面及内部缺陷,严重危害零件性能,成为阻碍金属增材制造技术发展的重要因素,限制了该技术在关键领域的应用.及时获取缺陷信息有助于调整工艺参数、改进制造过程,进而提升零件品质,同时缺陷信息也可用于指导零件的后续加工和处理.因此研究缺陷的成形机理及相应检测技术对于提升金属增材制造技术水平具有重要意义.针对这一热点问题,本文首先对金属增材制造中的常见缺陷类型做简要梳理,总结其主要表现形式及成因.随后综述近年来金属增材制造缺陷检测领域具有代表性的研究工作,主要针对过程特征量监测和在线无损检测两方面,并简述不同技术的应用范围.最后对缺陷检测技术的发展趋势进行展望.文章指出金属增材制造零件的质量提升可以通过检测方法和技术予以保障,目前众多的检测方法在精度及实时性等方面尚未满足实际使用要求,缺陷检测技术将向集成化和智能化等方向发展.

Defect detection technology in metal additive manufacturing

In metal additive manufacturing (AM), rapid material temperature changes and complicated material behavior inevitably lead to various types of surface and internal defects, which are detrimental to the performance of final parts, and hinder the development and application of metal AM in key areas. Acquiring defect information in time is beneficial for adjusting process parameters, improving manufacturing process, and elevating parts quality. Meanwhile, the defect information can be utilized to conduct subsequent machining and processing. Therefore, it is of significance to conduct research on defect detection technologies to improve AM technology and expand its applications. To resolve this issue, this paper introduces the common defects in AM parts and summarizes their origins. Then typical studies on AM defect detection technologies in recent years are reviewed, with a focus on the monitoring of process signatures and the online non-destructive testing methods. The application scope of different methods is also presented. Finally, the development trend of defect detection technology is forecasted. A conclusion is drawn that defects in AM are complicated and the parts quality needs to be assured by detection methods and technologies. However, methods proposed so far still cannot satisfy the requirement of AM, and the technology should be developed towards integration and intelligence in the future.