基于综合评价的SiCp/Al磨削表面质量试验

目的 针对高体积分数SiCp/Al加工表面缺陷复杂多样,提出其表面质量综合评价方法,研究磨削参数对SiCp/Al磨削表面质量的耦合影响规律,优化加工工艺.方法 基于SiCp/Al磨削加工表面缺陷,提出粗糙度综合指标SR为主、表面形貌为辅的表面质量综合评价方法,采用全因子试验方法分析低、高进给速度工况下主轴转速和磨削深度对表面质量的影响规律.借助Abaqus软件揭示SiCp/Al磨削表面形成机理,解释试验结果.结果 小切深(ap为5μm和20μm)时,粗糙度综合指标SR随着主轴转速ns的增加而先递减再增大;大切深(ap为40μm和80μm)时,SR随着ns的递增而递减或近似递减.低主轴转速(ns为2000 r/min和4000 r/min)时,SR随着磨削深度ap的增加(ap由5μm递增到80μm)而先增大再减小而后又增加;高主轴转速(ns为6000 r/min和8000 r/min)时,SR随着ap的增加而先增加再低进给量时减小或高进给量时增加.获得最佳磨削表面质量的最优磨削参数是:进给速度vf=50 mm/min,磨削深度ap=5μm,主轴转速ns=6000 r/min.兼顾磨削效率和表面质量的最优磨削参数是:vf=50 mm/min,ap=80μm,ns=8000 r/min.结论 表面质量综合评价方法的可靠性较高,主轴转速和磨削深度对表面质量的影响具有耦合性,减小磨削深度、采用适当主轴转速有助于改善表面质量.

Experiment of Grinding Surface Quality of SiCp/Al Based on a Synthetical Assessment Method

The work aims to propose a synthetical surface quality assessment method and analyze the influence of process parameters on the surface quality of high volume fraction SiCp/Al, as well as optimize the grinding process in order to solve severe and complex surface defects of machined SiCp/Al. Surface defects of machined SiCp/Al were observed via SEM to present a synthetical assessment method based on primarily the overall surface roughness indicator SR which integrates multiple indicators and secondly surface topography. The full factor experiments were carried out to analyze influence of spindle speed and grinding depth on surface quality at low and high feed rate conditions separately. Abaqus simulation was conducted to reveal formation mechanism of grinded SiCp/Al surface and then explain the experimental results. During the experiment, at smaller grinding depths (ap were 5 mm and 20 mm), the overall surface roughness indicator SR progressively decreased first as the spindle speed ns increased) and then increased as ns increased; at larger grinding depths (ap were 40 mm and 80 mm), SR progressively or approximately decreased as ns increased from 2000 r/min to 8000 r/min. Conversely, at lower spindle speeds (ns were 2000 r/min and 4000 r/min), SR increased first and decreased second and then increased as ap increased from 5 mm to 80 mm; at higher spindle speeds (ns were 6000 r/min and 8000 r/min), SR increased first as ap increased and then decreased at low feed rate or increased at high feed rate as ap increased. The optimized grinding parameters for the best grinding surface quality included feed rate of 50 mm/min, grinding depth of 5 mm and spindle speed of 6000 r/min; and the one for both grinding efficiency and surface quality included feed rate of 50 mm/min, grinding depth of 80 mm and spindle speed of 8000 r/min. Therefore, the synthetical assessment method of machined SiCp/Al surface has high reliability, the influences of spindle speed and grinding depth on the surface quality present coupling nature. Decreasing grinding depth and adopt appropriate spindle speed can improve the surface quality.