Simulation and Visual Control of Chip Size for Constant Surface Roughness

A visual cutting chip control system is designed to automatically adjust feed rate in order to maintain constant surface roughness in ball-end milling. The proposed visual control system has a modular structure, consisting of an optical vision system (OVS), an adaptive cutting chip size-control loop for a feed servo and a surface roughness in-process prediction model. The OVS is employed to acquire the cutting chip sizes form the camera. A division controller is used to control the chip size by modifying the feed rate and consequently maintaining surface roughness constant. Surface roughness is predicted based on the detected chip size. The efficiency of the chip control strategy is tested by series of simulation with various step changes in the cutter/workpiece contact area. For simulation purposes an experimentally validated milling plant simulator with an adopted feed servo drive model and a cutting chip size model is employed. An adaptive neural inference system (ANFIS) is established to effectively simulate the cutting chip size in ball end-milling. In simulation, the reference chip size and consequently the reference surface roughness are well maintained when the cutting-depth profile of a workpiece is varying step-wise or continuously. (Received in September 2014, accepted in March 2015. This paper was with the authors 2 months for 1 revision.)