Development of a Material Model for Visco-elastic Abrasive Medium in Abrasive Flow Machining

Abrasive Flow Machining (AFM) uses the visco-elastic properties of a polymeric carrier, combined with abrasive grains, as a tool for machining of difficult to reach geometries, such as holes or cavities. Due to the design of the workpiece holding device and variable flow rates, the complex shear modulus of the polymer can locally be influenced and thus a targeted removal on the workpiece can be produced. As a result there is a reproducible material removal, causing requested polishing, deburring or edge rounding. Due to shear thinning and visco-elastic behavior of the tool, the process simulation for AFM is very complex and has not been implemented yet including an exact physical material model. Initial machining parameters so far are based on experience and extensive experimental research. This publication gives an insight into the investigation of modeling the abrasive media in AFM by adapting the standard Maxwell model of elastomers and extending it to the Generalized Maxwell model. Assuming the material removal of the process being caused by the shear stressed dependent bonding of the abrasive grains, a fundamental material model, easy to be integrated in conventional simulation programs, is developed and presented in this paper.