MQLによるホブ切りにおける超硬合金ホブ材種の影響: 舞いツールによる基礎実験

摘要

This paper investigates the influence of kinds of cemented carbide hob materials coated with fully TiN and (Ti,Al)N coatings, in hobbing with minimal quantity lubrication (MQL) system compared with dry cutting in cutting performance, in terms of flank wear (tool life), crater wear and finished surface roughness. Experiments were carried out by simulating hobbing by fly tool cutting on a milling machine. The results obtained are summarized as follows. (1) When changing the kinds of hob materials, P10, P20 and P30, as a substrate, the P30 hob material showed a longest tool life, even if the kinds of coating films were changed. The tool life obtained with the fully (Ti,Al)N-coated tools is longer than that obtained with the fully TiN-coated tools. The flank wear reduction effect by MQL system, which prolongs the tool life compared with the dry cutting, was recognized. (2) Although the reduction effect was recognized in the crater wear, the thermal cracks occur on the rake face of both fully TiN-and (Ti,Al)N-coated P30 tools. (3) The MQL system decreases the surface roughness with all of the cemented carbide hob materials and the coating films tested. (4) From the viewpoints of the tool life, the crater wear and the surface roughness, the use of MQL system for the fully (Ti,Al)N-coated P30 tool is effective.%ホブ切りにおいて，従来より高速度鋼ホブを用いて，多量のrn不水溶性切削油を供給して歯切りすることが一般的に行われてrnいる．しかしながら，最近，多量の切削油剤を使用した場合に，rnミストや臭気による作業環境の悪化，使用後の廃液処理での環rn境汚染などの問題がこれまで以上に取り上げられるようになっrnてきている．