Experimental investigation of novel internal thread fabrication: A drill thread milling

Abstract

In this study, a novel method for fabricating internal threads called drill thread milling (DTM) was experimentally investigated. DTM is a fabrication process that combines drilling and thread milling into a single process, thereby eliminating the need for a pilot hole and making it a viable alternative to existing methods. To optimize the DTM process, the characteristics of DTM must first be understood. In this study, the machining characteristics of DTM were examined using a variety of materials and machining parameters. The results were then compared with those obtained using the tapping method. During the experiments, the machining force and vibration were recorded, and the results indicated that DTM required less machining time than did the tapping method. However, DTM exhibited an additional periodic components in the machining force, which could resulted in chatter. In certain materials, a tool offset was required to pass the thread gauge, indicating substantial tool deflection occurred during the machining process. The examination of the resulting threads revealed that, for the same thread depth, DTM required a shallower hole than that required in the tapping method.