Papers by Keyword: Softness Abrasive Flow

Abstract: As it was difficult to solve the near wall characteristics of flow field in softness abrasive flow machining (SAFM) on mould structural surface, a method for simulation the flow characteristics based on the low Re number k-ε model was proposed in this paper. The U-shaped tube was used as specific simulation object. The motion law of particles and related parameters were calculated and the precision machining mechanism of SAFM was discussed. Simulation results show that the micro cutting of abrasive flow mainly appears as the transposition of cutting location influenced by the particle pressure, and as the variation of machining efficiency influenced 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 with the machining requirements. By tracking near-wall particles, it can be confirm 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 SAFM method can be reaffirmed.

Abstract: As it was difficult to solve the near wall characteristics of flow field in softness abrasive flow machining (SAFM) on mould structural surface, a method for simulation the flow characteristics based on the low Re number k-ε model was proposed in this paper. The greater curvature of small size tube was used as specific simulation object. The motion law of particles and related parameters were calculated and the precision machining mechanism of SAFM was discussed. Simulation results show that the micro cutting of abrasive flow mainly appears as the transposition of cutting location influenced by the particle pressure, and as the variation of machining efficiency influenced 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 with the machining requirements. By tracking near-wall particles, it can be confirm 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 SAFM method can be reaffirmed.

Abstract: The soft abrasive flow machining was proposed for solving the problems of difficult contact finishing in course of mould manufacturing. It could reach the specular level and control turbulence abrasive flow. Based on the topological structure transformation of LSM, a two- dimensional model of the two-phase flow is established. This mechanics model with the SIMPLE (semi-implicit method for pressure-linked equations) algorithm incorporated is used to simulate the movement of the turbulent flow by using of k-ε model. The computed results show that this 2D model can preferably simulate the movement of the two-phase flow, and the characteristic parameters of abrasive two-phase flow are derived.

Abstract: Considering the demand of precision in mould structural surface polishing method, a new method based on soft abrasive flow machining(SAFM) was proposed, which was supposed to achieve polydirectional and multi-angle cutting acting on the surface of the workpiece by utilizing the irregular motion of both wear particles and the media in turbulence flow. Thus as the monodirectional marks on the machined surfaces was eliminated, the disadvantage in machining precision in conventional abrasive flow machining(AFM) method would be overcome. According to the particle distribution characteristics of SAFM, a two-phase dynamic model of abrasive flow oriented to SAFM combined with Discrete Phase Model(DPM) was built to analog simulation with the software Fluent. Sequently the mechanism of ultraprecision machining towards mould structural surface was analyzed briefly. Simulation results show that the abrasive efficiency along the flow passage can be influenced by the development of turbulence and the distribution of dispersed phase. Thus there a specific region can be obtained in the passage in which the abrasive efficiency is relatively stable.