皮籠石 紀雄

丸みのある切れ刃に作用する切削抵抗 : 第1報, 切削抵抗に関する基礎的な検討

Undeformed chip thickness may be smaller than radius of cutting edge at small feed rate when workpieces are cut by a finishing tool with large round corner. Therefore, in finish cut, sharpness of cutting edge has to be taken into consideration in cutting process. The purpose of this study is to find mechanism of cutting force occurrence at smaller undeformed chip thickness than radius of cutting edge. In this study, the effects of cutting edge radius both on cutting force and on burnishing force were investigated in orthogonal cutting. Furthermore, contact length between tool flank face and woprkpiece during cutting was measured in order to consider the relation between the burnishing force and the contact length. As a result, the conclusions were reached as follows. First, the following parameters very inversely as the nth power of undeformed chip thickness normalized by radius of cutting edge: (i) cutting forces per unit area of chip section, (ii) specific burnishing force defined as burnishing force divided by undeformed chip thickness and by width of cut, and (iii) specific burnishing length defined as burnishing length divided by undeformed chip thickness. Second, cutting force occurring on flank face of ploughing force is greater than excessive cutting force caused by reduction of rake angle on round face of cutting edge.