超硬リーマによる加工精度に関する研究 (第2報)

下穴偏差の切削状態に及ぼす影響

抄録

Cutting action, effected by the alignment error between pre-bored hole in workpiece and spindle axis under rotation, is examined in reaming steel by means of a dynamometer, which is specially designed to measure torque, thrust and radial forces in two directions (X, Y). From these results, relationships between variable components of cutting forces and sectional profile of machined hole are discussed. In rotation of tool axis, eliptical movement is mostly observed. It causes the difference of two variable components of radial force (ΔR_X, ΔR_Y), which are related to the variable torque. Variable force components during one spindle rotation have an influence on the eliptical profile in the machined hole section, and variable components, whose frequencies correlate to number of tool teeth, influences the number of lobe in multi-cornered profile. Eliptical movements of tool axis affect on the state of metal-flow in sub-surface of hole wall, and cause the roundness error. Since the alignment error is unavoidable in hole-making operations, the ideal cutting motion cannot be performed in reaming process.