Robot Trajectory Planning for High Quality Thermal Spray Coating Processes on Complex Shaped Components

Industrial robots are widely used in thermal spraying operations in order to assure process accuracy and reproducibility, as well as to increase worker´s safety. Robot path planning for the coating of free form geometries keeping constant the kinematic parameters can lead to complex robot paths and in some cases to unreachable robot configurations. An external rotational axis in coordinated movement with the robot can be used to manipulate complex shaped components during the spraying operation and to simplify the robot movement. Moreover, the robot kinematics, which define the spraying path, spray angle, spray distance and spray velocity, are key parameters to control the heat and mass transfer to the substrate during the coating deposition, and they influence therefore the development of residual stresses. The present work describes the off-line planning of robot trajectories for thermal spraying operations using an external rotational axis taking into consideration the heat transfer to the component.