CUTTING FORCE MODEL FOR MULTI-TOOTHED CUTTING PROCESSES AND FORCE MEASURING EQUIPMENT FOR FACE MILLING

This article presents a mechanical cutting force model for multi-tooth cutting processes, where initial position errors in radial and axial direction, eccentricity and edge wear are taken into account. The cutt ing forces are presented for each individual cutting edge, and in a sy stem of coordinates where one axis is parallel to the cutting speed ve ctor at any instant. The process parameter cutting resistance, C-r, is derived from the measured main cutting force F-M. C-r should be regar ded as a parameter since it is always increasing with decreasing value s of theoretical chip thickness h(1). A new way of measuring cutting f orces in multi-tooth cutting processes is also presented. Eight cuttin g force components are measured on the tool close to each of the four cutting edges. The aroused signals are filtered, amplified, A/D-conver ted and put together in a serial stream for transmission through a hol low spindle via a fibre optic cable. The signals are sent from the rot ating spindle to the frame of the machine over an air gap with Light E mitting Diodes. They are then demultiplexed, D/A-converted, and stored in a PC-based eight channel oscilloscope. With this measurement equip ment it is possible to directly measure the cutting forces acting on e ach individual cutting edge.