In this paper, Cutting force adaptive controller which uses feed rate as a input and uses Spindle speed sequentially to increase the productivity is proposed. Because cutting force can be lowered by increasing cutting speed, the machining time can be shortened by the controller which raises the spindle speed instead of reducing feed rate.
The cutting force is measured indirectly by the spindle current. Feed rate and spindle speed can not be controlled simultaneously due to the current of acceleration and deceleration. For this reason, this controller uses spindle speed when feed rate approach the lowest limit.
The increase of the spindle speed prolonged the response time by the relationship between cutting force and change of feed rate. The controller showed faster and stable response about the step input and changes of machining condition by Direct MRAC considering spindle speed. This feature is foundation of the controller which uses feed rate and spindle speed to control cutting force and reduce machining time. Through the experiment in this paper, the machining time was shortened than the previous controller which uses only feed rate to control cutting force.
