Analysis of tool wear mechanism and wear effect of drill thread mill machining

This study delves into investigating tool wear in drill thread mill (DTM), a specialized threading process known for its adaptability and lack of need for a pilot hole. While previous research extensively addresses tool wear in turning and milling processes, studies focusing on thread-making processes, especially DTM, are relatively scarce. To address this gap, our research aims to comprehensively explore wear morphologies, mechanisms, and their impacts on dimensional integrity and cutting parameters of DTM tools. We employ optical microscopy to elucidate wear progression and mechanisms and assess the effects of tool wear on dimensional accuracy of threaded holes and cutting parameters like cutting forces and vibration. Our findings reveal that the flank side experiences more significant wear compared to the rake side, with thread upper and thread lower cutters being the most heavily worn. We observe adhesion, coating delamination, built-up edges, and chipping in the wear mechanisms. Notably, wear predominantly affects lateral cutting forces, whereas thrust forces are less impacted. Although vibratory analysis can indicate wear progression, its efficacy is inferior to that of cutting force analysis. Moreover, wear significantly affects thread dimensional quality, particularly the effective diameter, necessitating compensation after the 130th hole.