A METHOD OF CHOOSING AN OPTIMAL CLAMP OF FASTENING FLEXIBLE WORKPIECE MAINLY AT FACE MILLING PROCESS

摘要

A method of choosing an optimal clamp of fastening flexible workpiece mainly at face milling process, in which in the first step, chosen workpiece is fixed to the machine tool's table with the use of fastening screws, under the first steady screws' tightening torque, then in the place of expected machining, the workpiece is excited with the use of the favourably modal hammer, and, in a known manner, frequency is measured and vibration amplitude spectrum is registered, and next the cost function corresponding to the work of cutting forces in the direction of cutting layer width, is determined using following formula $L={\displaystyle \sum _{\alpha =1}^{i_{\alpha }}}{b}_D{f}_{\alpha }^2\frac{\frac{\mathit{\pi n}}{30}}{{\left(\frac{n}{60}\right)}^2-f_{\alpha }^2}\sin \left(\frac{2\mathit{\pi n}}{60f_{\alpha }}\right)\mathop{\mathrm{image}}$ where:α- amplitude spectrum peak number,i_α- number of the identified amplitude spectrum peaks,b_D - nominal cutting layer width [mm],f_α - frequency of amplitude spectrum peak no. α [Hz],n - spindle speed [rev/min],after that in the second step, the second screw tightening torque is set down and in such defined conditions of clamping one is doing as in the first step, and next the respective steps are repeated for a finite number of technologically justified screws tightening torques, whereas the required torque is selected for which a value of the work of cutting forces in the direction of cutting layer width, in the other words the cost function L, is minimal.