Review: Cutter-marks on wooden workpiece surfaces when peripheral milling; Part 2: Strategies and concepts for reduction
: 5 - 13
Milling is one of the most important cutting procedures in the wood industry. It allows planing, profiling and shaping of workpiece surfaces with a high chip-removal rate. This is possible because of a fast rotary cutting motion of the tool, the possibility to place many cutting edges on the tool circumference and a fast linear feeding motion of the workpiece or the tool. Due to these different kinds of motions (rotary and linear) the resulting effective motion during the cutting process follows a prolonged cycloid. Periodic waves are formed on the workpiece surface due to this cycloid motion. These surface patterns, called cutter-marks, may be visible on the machined surface after cutting and mainly influence the workpiece quality. Further surface machining steps are required, like sanding or slicing to meet the required standards of surface quality and roughness. Therefore, extra efforts and costs are incurred, as well as additional production steps and time, in order to finish shaping the workpiece. This is why researchers have been looking for possibilities to lower or avoid these cutter-marks for some time. Beside the description and the analyses of the geometry of cutter-marks, magnitudes of disturbance, mechanical and mechatronic approaches and alternative procedures will be introduced, discussed, compared and presented in the paper. Especially mechatronic approaches using modern hardware can improve this situation by basically adjusting the cycloid motion track when the cutting edge approaches the work piece. In this way, the effective motion of the cutting edge is changed to a nearly linear motion by means of piezo-electric actuators or magnetic bearings. First successful set-up and experiments will be shown.