考虑刀具磨损的铣削加工精度可靠性分析及工艺优化设计

Accuracy reliability analysis and process optimization design of milling processing considering tool wear

针对难加工材料铣削过程存在的加工精度低、刀具寿命短等问题,建立了考虑刀具磨损的铣削加工精度可靠性模型,并进行了加工精度可靠性分析与工艺优化设计。利用高斯过程表征刀具磨损动态误差,结合某BC轴数控机床运动误差与刀具制造误差建立铣削加工精度可靠性模型,从而运用基于单循环Kriging代理模型的时变可靠性分析方法求解可靠度值;建立以加工效率最高为目标、期望加工精度可靠度和刀具寿命为约束条件的铣削加工工艺优化设计模型,并以序列二次规划法求解优化设计模型,确定最佳工艺参数值。优化结果表明,经工艺参数优化设计后,加工效率提高11.10%,加工精度可靠度与刀具寿命分别达到99.29%和42.37 min,为难加工材料铣削加工工艺参数选择提供了一种有效的方法。

Aiming at the problems of low machining accuracy and short tool life in the milling process of difficult-to-cut materials,the reliability model of machining accuracy considering tool wear was established,and the accuracy reliability analysis and process parameters optimization were carried out.Gaussian process was used to characterize the dynamic error caused by tool wear,and the reliability model of machining accuracy was established by combining the driving error of BC-axis machine tool with the tool manufacturing error.The single-loop Kriging surrogate modeling for time-dependent reliability analysis method was used to solve the reliability value.With machining efficiency as the optimization object and reliability of machining accuracy and tool life as the constraint condition,the model of optimization design was proposed.The sequential quadratic programming method was used to obtain the optimum process parameters.The results proved that the machining efficiency was improved by 11.10%,the reliability of machining accuracy and tool life reached 99.29%and 42.37min respectively after optimization design,which provided an effective method for the selection of process parameters in the milling process of difficult-to-cut materials.