Process-integrated quality assurance in wood machining centers with the help of image processing

Abstract

With rising feed rates of wood working machines, it is important to realize a process-integrated quality assurance. The quality control of produced workpieces is mainly carried out by the operator. As his capabilities are limited, an automated quality control system can help to assure a constant quality level. Due to the high production speeds, only an optical measurement can be used. While CCD-camera-based control systems are generally applied in wood working, no approach has been made so far to measure the surface roughness which is caused by the machining of the workpiece. This paper presents two different quality control systems for an assessment of the surface quality of a workpiece. In planing of solid wood, the size of the waves on the surface is most significant for workpiece quality. An image processing system has been developed which measures the width of the waves by means of a special illumination. In machining chipboards, the size and number of cracks in the edge are very important. Here, a camera-based system is presented which is able to measure the complete workpiece edge even at high feed rates with a sufficient resolution.