Drilling torque control using spindle motor current and its effect on tool wear

Drilling torque was estimated using the spindle motor current and controlled through feedrate manipulation for the reduction of drill wear. A PID controller was used to control the cutting torque measured indirectly from the spindle motor current. The effect of cutting torque control on drill flank wear was also investigated. Experimental results showed that the drilling torque was well-regulated at a given reference level and the risk of drill failure and drill flank wear were reduced remarkably through cutting torque control. Moreover, the suggested cutting torque control system does not disturb the cutting process and is practical in an industrial environment.