关键词: 不等前角, 变螺旋铣刀, 侧铣, 铣削力, 切削力系数辨识

Abstract: Variable helical end mills with unequal rake angle maight effectively suppress milling chatters, which significantly improved the machined surface quality and simultaneously reduced the risk of tool breakages, however, due to the unequal geometric parameters of each cutting edge, the existing models had difficulty to accurately predict the cutting forces, hence, a new instantaneous milling force modeling and coefficient calibration method were proposed. Firstly, the geometry and position relational expression of the cutting edges for variable helical circular-arc end mills were given, then considering the tool runout and variation of geometrical parameters of cutting edges, an instantaneous uncut chip thickness calculation and element cutting force prediction model was established; Subsequently, a nonlinear optimization method to simultaneously calibrate the cutting force coefficients and tool runout parameters was proposed, and an efficient algorithm for solving the model parameter initial values was also given based on linear least squares and oblique cutting theory. The experimental results show that the amplitude and waveform of predicted cutting forces are consistent with the measured ones with errors of less than 15%, verifying the effectiveness of the proposed model.

Key words: unequal rake angle, variable helix end mill, flank milling, milling force, cutting force coefficient identification