Development of a laser cleaning robot system for the processing of 3D surfaces

Laser cleaning based on laser ablation processes has the potential to remove dirt, over painting and other surface contaminants without touching the surface and without using any chemicals. It is already widespread in the semiconductor, automotive, and aerospace industries due to its lower costs, higher throughput and reduced environmental and toxicity problems compared to other cleaning methods. Currently, portable hand-held laser cleaning is the mostly used device for coating removal. The advantages of the portable hand-held laser cleaning lie in flexibility and convenience of use. However, with this mode of operation, it is not possible a precise control of the geometric parameters of the ablation process (focal length, angle of incidence, etc) or others such as the scanning speed, which are decisive to ensure effective, controlled and reproducible cleaning, especially in the case of 3D workpieces. In this sense, it must be said that laser processing of 3D surfaces (cleaning, micromachining, etc) is not a completely solved issue nowadays, and most of the proposed solutions are based on quasi 3D or 2.5D approximations. In this paper it is presented a laser cleaning robot system for the processing of 3D surfaces. It is based on the integration of a 6-degree-of-freedom (DOF) robotic arm with a laser source and a three-dimensional surface capture system to automatically generate the laser cleaning path. The manipulator allows displacements and changes of orientation of the object to be processed following the programmed paths in a full 3D solution. Furthermore, the hardware and software to coordinate the robot and the laser on/off was developed. Experimental results show the effectiveness of the proposed method which improves the efficiency of the automatic laser cleaning of 3D objects and further promotes the application to other ablation processes.