Creation of cutting part of polycrystalline diamond-end mills and finishing of the cutting edge(Outline of Doctor Thesis)
渡邉, 健志Takeshi, Watanabe
日本工業大学研究報告 = Report of researches, Nippon Institute of Technology
142 , 2016-02
In this study, a new design measures and manufacturing method for a cutting part of polycrystalline diamond (PCD) end mills is proposed. In the first part of this study, optimal shapes of the cutting part of the PCD end mills, including square-, ball-, and radius-end mills, are proposed from the viewpoint of the mechanical properties of PCD, the cutting ability, and tool life. Furthermore, the manufacturing method of the PCD end mills is investigated. Namely, PCD is difficult to grind when shaping the cutt ing part because it is the hardest material. Instead of the conventional grinding process, the author proposes the wire electric discharge machining (W EDM) method, which is a considerably different process from the conventional one. In this study, produc tivity and accuracy by the W EDM are discussed. As a result, the author was able to demonstrate the effectiveness of the proposed PCD end mills from the evidence of the excellent cutting test results in the cutting experiment In the second part, the author investigates an effective polishing method of the cutting part of the PCD end mill made by W EDM, to improve the accuracy of the cutting edge. As a result of this investigation, a new polishing method of using an ultrasonic -vibration-assisted abrasive process is proposed. First, the author shows the advantages of the new polishing method by analyzing the polishing mechanism. The effectiveness is also demonstrated by the results of a polishing test of the cutting edge of the PCD square -end mill. Second, an ultrasonic barrel polishing process is proposed and its advantage is proved by the results of the polishing test of the cutting edge of the PCD ball-end mill. In addition, a high -precision adjustment grinding process for PCD ball-end mills and reconditioning method of used cutting edges are proposed.