Compensation strategy for positioning inaccuracies in robot-based laser structuring

Laser structuring is used to texture complex 3D geometries, such as moulds for plastic injection moulding. However, due to the complex plant technology, common machines for laser structuring are very expensive and require lots of space. We developed a laser-structuring module which can be held by an industrial robot for large-area structuring. This can reduce the investment costs in the technology by up to 80%. The precision of the handling system is of major importance for laser-structuring. We developed a strategy to compensate for system-related positioning inaccuracies of the robot. For this purpose, an inline camera is used for a target-actual comparison. The camera system is able to detect reference markings as well as features of the texture itself. During the structuring process, the position error of the robot is compensated adaptively by determining the difference between the target and actual position in the region of interest and applying the difference to modify the toolpath accordingly.