Abstract: In allusion to the problem of tiny scale structural surface machining in mould manufacturing course, a new no-tools precision finishing method based on solid-liquid two phase softness abrasive flow SAF is brought forward. By setting restrained component for the machined surface, restrained flow passage is constructed. Using the wall effect of SAF, no-tools precision machining for tiny scale structural surface can be realized. By studying on Preston equation and Preston coefficients, selection criteria of particles for SAF machining are confirmed, and cutting empirical formula for SAF machining are obtained. Realizable model and SIMPLEC algorithm are used for numerical analyzing pressure and velocity distribution of SAF, and particles pressure on surface with different particle sizes are also simulated, the best particle size which is suit for SAF machining are derived by simulation results. Based on results of theoretical and simulation analysis, SAF experimental platform is constructed, machining experiments with different inlet conditions have been done, and impacts of inlet condition on workpiece surface shape are analyzed. Experiment results show that tiny scale structural surface machining can be realized, and machining method based on SAF can improve surface accuracy of tiny scale mould structural surface effectively.

Key words: Machinability, Preston equation, Softness abrasive flow, Structural surface