Al7075-T6薄壁件铣削残余应力建模及工艺参数优化

PREDICTION MODEL OF RESIDUAL STRESS AND OPTIMIZATION OF PROCESS PARAMETERS IN MILLING OF AL7075-T6 THIN-WALLED PARTS

为了实现铣削表面残余应力的准确预测及优化,以Al7075-T6铝合金薄壁件为研究对象,首先通过对正交铣削模型受力分析,提出了一种同时考虑加工参数和铣削力、热的表面残余应力预测模型,并与传统指数型经验模型对比,证明改进残余应力预测模型的优越性。利用田口算法和平均信噪比分析工艺参数对工件表面残余应力影响的显著性,获得残余压应力生成的最佳工艺参数组合,实现残余应力的优化,并用实验和预测模型对优化的工艺参数进行验证。结果表明:与传统指数型模型相比,改进的X、Y方向表面残余应力模型预测精度分别提高了18.5%和8.2%;参数优化后的工件X、Y方向残余压应力分别增加了16.0%和6.3%,同时表面粗糙度值并未明显下降,以上成果为航空航天薄壁件残余应力的主动控制提供了理论基础。

In order to achieve accurate prediction and optimization of milling surface residual stress. In this paper, Al7075-T6 aluminum alloy was taken as the research object. Firstly, a surface residual stress prediction model was proposed by analyzing the forces of orthogonal milling model and considering the machining parameters, milling force and heat. Compared with the traditional exponential empirical model, the superiority of the improved prediction model was proved. Taguchi algorithm and average signal-to-noise ratio were used to analyze the significant effect of process parameters on residual stress on workpiece surface, and the optimal process parameters for residual compressive stress generation were obtained. The optimized process parameters were verified by experiment and prediction model. The results show that compared with the traditional exponential model, the prediction accuracy of surface residual stress in X direction and Y direction is improved by 18.5% and 8.2%, respectively. After parameter optimization, the residual compressive stress in X and Y direction increases by 16.0% and 6.3%. The surface roughness value did not decrease obviously, which provides a theoretical basis for active control of residual stress of aerospace thin-walled parts.