工具すくい面上に作用する応力の食いつき角による変化

断続切削時における食いつきの研究 (第3報)

抄録

A primary factor of the wide fluctuation of tool life owing to an engagement angle E_a in face milling may expect that the transient stresses in the cutter tooth are varied with the angle E_a, and then, their transient stresses distribution upon the rake surface for the various angle E_a at milling are analyzed by photoelastic experimental method, in which the lead alloy plates are cut with a tool of epoxy resin. Moreover, it makes a model of stresses distribution from these results and this model is applied here for the computational stress analysis in the tool on the same cutting process by the finite element method and these computed values are verified with the photoelastic experimental results, after that, it makes another attempt to calculate about the varied tool wedge forms and boundary conditions. The main results have proved as follows. When a rake surface of tool contacts at the outward face of workpiece with a positive engagement angle and it bigins biting from apart point of the tool edge, the parallel stress σ_y for the rake surface acts only at a neiborhood of tool edge as tensile stress, at last, their stresses turn to compression one in entirely biting to the tool edge. Thereupon, these tensile stresses are induced by the friction force of chip flowed on the rake surface. Such the alternating stresses acted at the neiborhood of tool edge become a cause of chipping or breakage and it is supposed that stresses exert a great influence upon the tool life.