Analytical method for softness abrasive flow field based on discrete phase model

Abstract

Aiming at the problem of difficult contact finishing for mini structural surface in course of mould manufacturing, a new no-tool precision machining method based on soft abrasive flow machining (SAFM) was proposed. It allocated restrained component near surface machined, constituted restrained abrasive flow passage, and made the surface become a segment of passage wall. It could control turbulence abrasive flow in restrained passage, realize micro cutting for passage wall, and utilize the irregular motion of abrasive flow to eliminate the mono-directional marks on machined surfaces, and the precision could reach the specular level. A two-phase dynamic model of abrasive flow oriented to SAFM combined with discrete phase model (DPM) was established, the law of two-phase flow motion and the related physical parameters was obtained by corresponding numerical simulation method, and the mechanism of precision machining in SAFM was discussed. Simulation results show that the abrasive flow machining process mainly appears as translation of ablating location with the influence by granular pressure, and as the variation of machining efficiency with the influence by near-wall particle velocity. Thus via control of the inlet velocity and its corresponding machining time, it is supposed to work out the machining process according to the machining requirements by using the Preston equation to seek the relationship among velocity, pressure and material removing rate. By tracking near-wall particles, it can be confirmed that the movement of near-wall abrasive particles is similar to stream-wise vortices. The cutting traces on workpiece surfaces assume disorderly arrangement, so the feasibility of the SAFM method can be reaffirmed.