Modeling and simulation of industrial waterjet stripping for complex geometries

Industrial waterjet stripping/cleaning is a prime example of a dull, dirty, dangerous manufacturing process that is ripe for automation, yet it remains a manual task in most instances due to complex workpiece geometry and/or low-volume, high-mix production. Recently developed automated tool trajectory planning algorithms and collaborative path planning frameworks offer a potential solution but are of limited use without corresponding process models and simulation tools to evaluate toolpath quality. Existing process models do not consider the spray impingement angle or the cumulative effect of successive tool passes—both of which are inevitable when spraying geometries that possess concave and/or discontinuous features. This research proposes a novel process model that includes impingement angle and accounts for the cumulative, ablative nature of the process. It also develops a simulation algorithm that applies this model to complex geometries while considering shading effects caused by protrusions and overhangs. Model parameters are determined via a design of experiments approach and nonlinear regression, and verification experiments on complex test parts show good agreement between predicted and measured results. Paired with the aforementioned trajectory planning tools, this research represents a complete robotic process planning solution for waterjet stripping/cleaning of complex parts in high-mix, low-volume manufacturing.