CFD Simulation of the Abrasive Flow Machining Process

For the Abrasive Flow Machining (AFM) process, a highly viscous polymeric carrier mixed with abrasive grain is used for deburring, edge rounding and the general improvement of surface quality of workpieces with complex geometries. At present, time-consuming and expensive feasibility studies and parameter analyses are required for each new application. According to a market study of 2012, more than 50% of AFM users request the availability of a process simulation to model and optimize the flow and predict the results by use of numerical methods. The key challenge is the accurate description of the complex behavior of the viscoelastic abrasive medium. This paper examines a CFD approach to the flow simulation by integrating the non-Newtonian, shear-thinning characteristics of a Maxwell fluid into the inelastic Navier-Stokes equations. With the implementation of the viscoelastic material model in ANSYS CFX, physically reasonable results can be achieved and validated by experimental machining results of additively manufacturedSLM workpieces. The results for flat, reference workpieces as well as for turbine bladesare discussed and compared to experimental results.