Strategies, concepts and approaches to avoid cuttermarks on wooden workpiece surfaces

Milling is one of the most important cutting procedures in the wood industry. It allows shaping of workpiece surfaces with a high chip-removal rate. This is possible because of a fast rotary cutting motion, the possibility to place many cutting edges on the tool circumference and a fast linear feeding motion. Due to these different kinds of motions the resulting effective motion follows a prolonged cycloid which forms periodic waves on the workpiece surface. These surface patterns, called cuttermarks, may be visible on the machined surface after cutting and mainly influence the workpiece quality. Further surface machining steps are required to meet the demanded standards of surface quality. This is why researchers have been looking for possibilities to lower or avoid these cuttermarks. Beside the description and the analyses of the geometry of cuttermarks, magnitudes of disturbance, mechanical and mechatronic approaches and alternative procedures will be introduced and discussed. Especially mechatronic approaches can improve this situation by basically adjusting the cycloid motion track. 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.