DETERMINATION OF MINIMUM LIMITING AXIAL DEPTH OF CUT FOR 2½D POCKET MACHINING BASED ON RECEPTANCE COUPLING

A minimum limiting axial depth of cut guarantees stable machining for any cutting speed and is selected as the height of the z-level of cut used for 2 D pocket machining. It is determined based on the frequency response function (FRF) and receptance coupling substructure analysis (RCSA) to minimize experimentation. For process planning considerations, long cutters are more preferable for deep pockets to reduce the number of z-levels of cut. However, the higher cutter flexibility results in bouncing effect during impact testing. To overcome this problem, a string test is proposed in which the cutter tip is deflected by a string and receptance measured for free vibration. In this work, the FRF at the tip of cutters with different geometries was measured with both the tests to study the effect of geometry on receptance. The prediction of experimentally calibrated RCSA models shows good agreement with the measured receptance. The results also suggest the suitability of string test for flexible cutters. Finally, a reference plot of the variation of limiting axial depth with cutting geometry and conditions is generated based on the predicted receptance. The plot provides a priori determination of the stable limiting axial depth of cut which facilitates the automatic generation of process plans for 2 D pocket machining.