Expanding the possibilities of position error compensation in CAM for PKM milling machines

PKM milling machines have promising advantages compared to SKM milling machines, such as a higher stiffness-to-mass ratio, enabling a better dynamic behaviour. Errors in the PKM driving chains cause position errors of the end effecter. Its parallel construction and non-uniform position error patterns make finding the error sources a challenging task. This paper presents the application and expansion of a position error reduction method. Measured and predicted error patterns, the latter generated by a kinematic model, are compared and the most likely error source is found. With this information, the NC code is systematically modified and the PKM machine can be adjusted.