The structural surfaces are not easy to be finished by polishing tools. A new method of precision finishing based on low viscosity liquid-solid two-phase abrasive flow was provided. With this method, flow passage was constructed by restraining modular block and structural surfaces to be machined. Liquid-solid two-phase abrasive flow was made by mixing low viscosity liquid with micro abrasive particles according to a definite volume fraction. When the turbulent abrasive flow passed through the constructed flow passages, the surface of flow passage will be finished gradually by frequent action of micro force and micro-scale machining of the abrasive particles. Disordering of the surface machining vein was easy to be realized under the condition of abrasive flow turbulence, which can improve surface quality. Therefore, contrast researches of pressure, velocity and turbulent kinetic energy of abrasive flow in the flow passage constructed by restraining modular blocks before and after optimization were carried out. The conclusion is that uniform turbulence is easy to be formed after the restraining modular block is optimized. Finishing experiments were carried out on a self-made low viscosity liquid-solid two-phase abrasive flow machining equipment. The experimental results indicate that the uniform surface roughness is obtained after the restraining modular block is optimized. And the surface roughness value reduces from Ra=93.28nm to Ra=42.78nm after 50 hours’ finishing, which proves the feasibility and effectiveness of this method.

abrasive flow, restraining modular block, turbulence, finishing

针对结构化表面不易采用工具实现精密光整加工的问题,提出了一种基于低黏度液-固两相磨粒流的精密光整加工新方法。该方法采用约束模块与被加工结构化表面构成磨粒流流道,将低黏度液体与微细磨粒按照一定体积分数混合形成液-固两相磨粒流,当磨粒流以湍流状态流经所构建的流道时,通过磨粒微力微量切削的频繁作用实现流道表面的逐步光整加工。由于磨粒流在湍流状态下易于实现表面加工纹理无序化,从而提高表面质量,因此对比研究了约束模块优化前后所构成的流道中磨粒流的压力分布、速度分布和湍动能分布,得出优化设计后的约束模块易于形成均匀湍流的结论。在自行搭建的低黏度液-固两相磨粒流加工装置上进行了光整加工试验,结果表明,经过50h的光整加工,工件表面粗糙度由Ra=93.28nm减小到Ra=42.78nm,从而证明了该方法的可行性和有效性。

磨粒流, 约束模块, 湍流, 光整加工

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