State of the art on internal thread manufacturing: a review

Thread profiles can be considered as mechanical components which contributed to improving the evolution of machines and devices throughout all the history of man. The great importance of using threaded components, in industries and everyday life, is related to the versatility that allows the assembly and disassembly of components exceptionally quickly. Basically, since its invention, the threading tool has been developed, and its geometry has been optimised. Besides, new materials for tooling and coatings have been developed, allowing a significant evolution in the threading process. Thus, this article provides a review, demonstrating the evolution and the main studies in threading processes in the last 20 years, showing the main results obtained and the influence of threading in manufacturing processes. The traditional threading operations such as machining and forming tapping were contextualised, showing the main research with the advances generated in these processes. Furthermore, special internal threading processes were also revised, demonstrating the current developments and their gaps for new studies. Finally, based on this review are proposed lines of research, considering the shortcomings of the contemporary and revised works, that can increase the number of technical information for all threading processes, optimising the current way of making threads.