A feasibility study of on-line drill wear monitoring by DDS methodology

A new approach to achieve on-line drill life monitoring is introduced using the Dynamic Data System (DDS) methodology. Changes in the thrust and torque of the drilling process were investigated. A static analysis provided poor correlation and low sensitivity between average thrust/torque and drill flank wear. The dynamic parameters (natural frequencies and damping ratios) of the drilling process were strongly related with the average drill flank wear. Hence, a new parameter “Normalized Damping Ratio” (NDR) was formed from the DDS analysis using the dynamic part of the signal which correlates with drill wear. The possibility of developing an on-line drill flank wear monitoring scheme using the NDR index is pointed out.