Development of Rheology and Computational Flow Model for Robotized External Finishing on Additively Manufactured Components

摘要

Stream finishing is accepted as one of the post processing operations. It is not only capable of grinding but also offers polishing of additive manufactured components, having advantages of larger material removal rates and controllable toolpath. We have developed a stream finishing model through semi quantitative prediction via computational fluid dynamics (CFD) simulations. The scheme couples the granular flow field with the material removal scheme by solving the granular flow using a continuum-based method. For the rheology, the media viscosity is determined to resolve the flow field so the pressure induced by the media and the material removal rate can be predicted. The model calibration involves developing a tribometer and using it to measure the media pressure for several scenarios based on the rotational speed of the drum (30 rpm), radial distances of the tribometer (100, 250, 400 mm), submerged depths (100, 200, 250 mm) and its glancing angles (0, 15°, 30°, 45°, 60°, 75°, 90°). The work is extended to study the media flow for a simplified square work piece. The results indicate that the particle velocities on the surface of the work piece predicted by simulations are comparable to those of experiments. They show similar patterns and magnitudes for the parameters tested, which demonstrate the capability of the model to correctly predict the granular flow field.