Cutting Disturbances in Hard Turning Process

Assumption of cutting disturbances in hard turning process (caused by variations in depth of cutting, high passive force Fp or small tool nose radius) could be confirmed with several indicators. These indicators can be monitored during turning process(forces, vibrations, sound, etc.) or after process has been finished (roughness, temperature, wear, etc). Variation of depth of cutting as well as its influence on lead edge angle and passive force Fp was therefore calculated on numerical model and procedure was followed by experimental tests . It was found that high chip thickness alteration occur because of cutting depth vary for a value of some 60 % and even more if Fp force signal is analyzing when machine tool has inadequate stiffness. Assuming that a hard turning is a semi finishing or finishing process, surface finish is of big relevance. Surface roughness is a consequence of both cutting disturbances and of tool/workpiece non-uniform loading distribution. Results of test indicates an optimal cutting depth for final pass when minimum surface roughness can be achieved what can be valuable for cutting regime determination. Furthermore, higher machine tool efficiency might be achieved..