研削砥石の選択標準

Abstract

In the case that a suitable grinding wheel is used under the optimum grinding condition, the purpose of grinding operation is attained. Even if the optimum grinding condition is established, the reasonable grinding operation cannot be done, when the selection of wheel grade is mistaken. So in grinding operations, the problem of wheel selection becomes most important. In this paper, the standard of wheel selection is considered on the theoretical basis. The results obtained are as follows : (1) The suitable wheel grade for grinding operation is given byE=1/-k5elog {1-mrθrJB√d0√kρc√υl/0.95k4 qR wV} orZg=mrθrJB√d0√kρc√υl/0.95k3 qR wVWhere, E : the modulus of longitudinal elasticity, Zg : the symbol mark of wheel grade, k4 : a constant, k5 : a constant, mr : the rate of normal force to tangential force, q : a constant, Rw : the flowing rate into the work of heat, θc : the critical grinding temperature corresponding to the occurence of burn mark, J : the heat equivalent of work, k : the thermal conductivity of a workpiece, ρ : the density of a workpiece, c : the specific heat of a workpiece, do : average grain diameter, l : the contact arc length between a wheel and a workpiece, V : wheel speed, υ : work speed, B : the width of grinding.(2) The standard of wheel selection in case that the type of grinding and grinding conditions change can be obtained.