丝锥是内螺纹加工的一种专用刀具，与车刀、铣刀等传统刀具不同，其加工属于半封闭、多切削刃成形加工方式。丝锥加工通常是机加工中的最后一道工序，丝锥质量的好坏直接影响了内螺纹的加工质量和加工效率。概述了市场上典型丝锥的类型、加工主要失效方式与失效机理，并查明丝锥刃口机加工缺陷及严重的黏结磨损和磨粒磨损是诱导丝锥切削性能与寿命显著降低的主因。因此，对丝锥进行表面处理也是行业的研究热点。在表面处理技术方面，重点分析了丝锥刃口钝化技术对丝锥刃口几何特征形态和加工性能的影响规律;同时也探讨了PVD技术类型及特点;在丝锥涂层方面，重点分析了氮化物涂层、含碳膜涂层和特征润滑膜涂层;在丝锥基体预处理方面，重点介绍了激光微织构图案对涂层结合力及刀具摩擦特性的影响规律;在涂层设计方法，重点介绍了常规氮化物、碳化物涂层和高熵合金氮化涂层的力学、物理和化学性质，以及涂层类型与丝锥切削性能和加工质量之间的关联性。最后，总结了单一表面处理技术在丝锥性能提升方面存在的问题，并提出了丝锥钝化+基体激光微织构+PVD自润滑涂层的复合技术方案。

Thread connection is one of the most common connection methods, which has been widely used in mold, aerospace, petrochemical, 5G communications, new energy vehicles and other industries. Tap is a special tool for small and medium-sized internal thread machining. It is almost the only effective process method for small thread hole machining. It is different from the traditional tools such as turning tools and milling cutters. It is closed for cutting and belongs to semi-closed and multi-cutting edge forming processing. Its quality directly affects the internal thread processing quality and processing efficiency. Starting from four common types of tap, the processing characteristics, processing materials and application scope of different taps are expounded and the geometric structures of taps are briefly introduced. Secondly, the common processing problems and failure forms of tap are introduced. Then, the effect of single surface treatment technology on the surface quality and processing performance of the tap is emphatically expounded, and the relationship between the surface treatment technology of the tap in China and abroad, including edge passivation, physical vapor deposition (PVD) nitride coating and special film and cutting performance is investigated. At the same time, the strengthening mechanism of different surface technologies is summarized, and the future prospect is put forward according to the research status in China and abroad.