RUNOUT REJECTION IN END MILLING THROUGH 2-DIMENSIONAL REPETITIVE FORCE CONTROL

Cutter runout presents an impediment to the attainable productivity an d part quality in machining processes. This study establishes a mechat ronic approach to compensate for cutter runout effect during multi-flu te machining in real-time. It is accomplished through measuring the ru nout-related cutting force component, formulating repetitive controlli ng commands, and manipulating the workpiece position to counteract the variation of chip load during the course of machining. In an end mill ing configuration, the approach has been realized with a two-axis test bed attached to the machining table. The test bed operates independen tly to the computer numerical control (CNC) servo loops of the machine tool, and it provides a fine range and high frequency motion of the w orkpiece. In this paper the development of the test bed is discussed i n terms of the hardware component design and the software controller f ormulation. Numerical simulation of the culling force in response to r epetitive learning control at the presence of runout disturbance is ex amined. To evaluate the feed-back system performance, experimental stu dy based on the implementation of both single- and two-dimensional con trols is presented in the context of cutting force regulation and part surface finish improvement.