干式铣削对IN718熔覆层表面残余应力及粗糙度的影响和预测研究

Study on the influence and prediction of surface residual stress and roughness of IN718 fused cladding by dry milling

  • 摘要: 与湿式切削相比,干切削属于发生界面固态接触的极端制造,苛刻的切削工况导致加工表面质量恶化。为了准确地预测IN718(Inconel 718)熔覆层干式铣削后表面残余应力及粗糙度,提出了一种基于遗传算法(genetic algorithm, GA)增强的BP神经网络预测方法,构造改进的BP神经网络预测模型,并探讨铣削参数对表面残余应力及粗糙度的影响。结果表明,GA-BP模型将残余应力和粗糙度预测误差由24.8%和18.9%分别降至6.6%和10%,对小样本数据拟合的优势突出;铣削表面残余应力和粗糙度随进给速度和径向切深的提高而增大,主轴转速对残余应力的影响并不明显;影响残余应力因素优先顺序为径向切深>进给速度>主轴转速,影响粗糙度因素优先顺序为进给速度>径向切深>主轴转速。

     

    Abstract: Compared with wet cutting, dry cutting is classified as extreme manufacturing due to the solid-state contact at the interface, leading to stringent chip conditions that cause deterioration of the machining surface quality. To accurately predict residual stresses and roughness after the dry milling of IN718 fused cladding, a genetic algorithm-enhanced BP neural network prediction method has been proposed. An improved BP neural network prediction model has been constructed to explore the effects of milling parameters on residual stresses and roughness. The results demonstrate that the GA-BP model reduces prediction errors of residual stress and roughness from 24.8% and 18.9% to 6.6% and 10%, respectively, underscoring its advantages in fitting small sample data. Surface residual stresses and roughness have been observed to increase with higher feed rates and radial depths of cut, with spindle speed having a less pronounced effect on residual stress. The priority sequence of factors affecting residual stress has been identified as radial depth of cut > feed rate > spindle speed, while for roughness, it is feed rate > radial depth of cut > spindle speed.

     

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