Vibrations in Metal Cutting : Measurement, Analysis and Reduction

Abstract: Vibration and noise in metal cutting are ubiquitous problems in the workshop. The turning operation is one kind of metal cutting that exhibits vibration related problems. Today the industry aims at smaller tolerances in surface finish. Harder regulations in terms of the noise levels in the operator environment are also central. One step towards a solution to the noise and vibration problems is to investigate hat kind of vibrations that are present in a turning operation. The vibrations in a boring operation have been put under scrutiny in the first part of this thesis. Analytical models have been compared with experimental results and he vibration pattern has been determined. The second part of the thesis deals with active vibration control in external turning operations. By embedding a piezo-ceramic actuator and an accelerometer into a tool holder it was possible to obtain a solution that can be fitted in a standard lathe. The control system consists of the active tool holder, a control system based on the filtered-X LMS algorithm and an amplifier designed for capacitive loads. The vibration level using this technique can be reduced by as much as 40 dB during an external turning operation.