Abstract:

A novel abrasive flow polishing medium is developed using methyl vinyl silicone rubber as the matrix， with the addition of dimethyl silicone oil， silicon carbide （SiC） abrasives， and other components. The rheological properties and machining performance of the medium are systematically evaluated. Through micro-morphology analysis and rheological testing （including creep compliance， stress relaxation， and dynamic modulus scanning）， the effects of the medium components on its viscoelastic behavior are investigated. Increasing the machining oil content enhances the fluidity， but an excessive amount （>20%） leads to a decrease in elasticity. Medium II （30% matrix， 20% machining oil， 45% SiC， and 5% thermal stabilizer） exhibits elasticity-dominant behavior （G^{\text{'}} >G''） over a wide frequency range （86.9‒628 rad/s） and shows significant shear-thinning characteristics， making it suitable for high-shear polishing conditions. Compared with the styrene-butadiene rubber-based medium， the methylvinyl polishing medium demonstrated superior thermal stability， wear resistance， and wall adhesion properties. The new medium is applied to screw polishing machining tests， and the results show that under tidentical parameters， the methyl vinyl polishing medium achieves an 89.23% improvement in surface roughness Sa of the screw， outperforming the 74.71% improvement rate of the styrene-butadiene polishing medium.

Key words: methyl vinyl, polishing medium, abrasive flow machining（AFM）, rheological property, surface roughness

摘要：

以甲基乙烯基硅橡胶为基体，添加二甲基硅油、碳化硅（SiC）磨料等，研制了一种新型磨料流抛光介质，并系统评估其流变性能与加工效果。通过微观形貌分析与流变测试（蠕变柔量、应力松弛、动态模量扫描），主要研究了介质组分对其黏弹性行为的影响，发现提高加工油含量可增强流动性，但过量（大于20%）会导致弹性下降，介质二（30%基体、20%加工油、45%SiC、5%热稳定剂）在宽频范围内（86.9~628 rad/s）表现出弹性主导（G^{\text{'}} >G''），且剪切稀化特性显著，适配高剪切抛光工况。与丁苯橡胶基介质对比，甲基乙烯基抛光介质展现出更优的耐热稳定性、耐磨性及壁面黏附性能。将新型介质用于螺杆抛光加工试验，结果表明：相同参数下，甲基乙烯基抛光介质使螺杆表面粗糙度Sa的降幅为89.23%，优于丁苯抛光介质的Sa降幅74.71%。

关键词: 甲基乙烯, 抛光介质, 磨料流加工, 流变性能, 表面粗糙度