Quantification of tool wear in micro-milling using Fast Fourier transform of accelerometer data

Tool wear in micromachining adversely affects the surface integrity and machining quality of the job in addition to sudden machine breakdowns. In this work, a simple, affordable real-time feedback system is generated which is capable to assess the tool wear in micro milling based on the spindle acceleration employing a motion processing unit. An in-house developed and commercialized machine of CSIR-CMERI named “Multi-Fab” has been used as a test setup on which a motion processing unit was mounted on the spindle. The acceleration data obtained during the micro-milling experiments were collected for three different tools with different pre-existing wear. The acceleration data was further processed using a fast fourier transform. The harmonics obtained from the FFT data clearly reveals distinguishing features to quantify the wear on the tool. The assessed tool wear could be displayed on the machine graphical user interface. The demonstrated method has potential in micromachining centers and shop floor as the feedback system is capable to provide tool condition to the machine operator.