Study of countermeasure and detection method for the polygonal deformation phenomenon in reaming

Abstract

Reaming is a finishing process for expanding the pilot hole and improving the accuracy of roundness. However, there is a problem that the tool vibrates during machining and the accuracy of the drilled hole deteriorates. When vibration occurs, the machined hole deforms into a polygonal shape. Such phenomenon is called polygonal phenomenon or pattern formation phenomenon, and it occurs in drilling and BTA deep hole drilling. The polygonal phenomenon of a hole is characterized by a helical twist in the processing direction. In this report, we verified the optimum unequal interval blade for an 8-flute reamer, which has not been implemented yet, from theory and experiment. Normally, the evaluation of the accuracy of borehole is verified by measuring the roundness. However, it is needed to confirm the occurrence of polygonal deformation during machining. Therefore, in this study, we also investigated the detection method of the polygonal deformation by measuring the phase variation of the cutting force.