Computer controlled machining equipment and centres that provide accuracy in the thousandth millimetres range, represent the pinnacle of woodworking technology. When cutting happens and, as a consequence, forces act in several different directions. For micrometer precision control of the cutting tool, work pieces have to be fastened securely, deprived from their degrees of freedom, to achieve maximum quality. The most frequent clamping method for pieces with planar surfaces today is fastening by a vacuum field. The vacuum-induced hold-down force, together with l0 and l (static and kinetic friction coefficients, respectively) creates the friction force that prevents the work piece from shifting.
The purpose of numerous measurements was the Analysis of the work piece movement. The shifting of the material upon intensive cutting or at the start of the cutting process is a frequent problem. In this article with two parts the friction coefficients when clamping work pieces of different wood species resp. wood materials by vacuum under different conditions are to be investigated.