考虑后刀面磨损及过缝冲击的拼接模具铣削力建模与实验研究

Modeling and experimental research on milling force of splicing die considering rear face wear and slit impact

针对拼接模具铣削过程中刀具易磨损引起铣削力变化的问题,对拼接模具铣削加工过程,提出了一种考虑球头刀后刀面磨损的铣削力建模方法。根据材料硬度的不同,把每一切削周期的切削厚度建成有关切削角度的函数关系,得到不同切削角度下的剪切力模型;同时将后刀面的摩擦效应力与后刀面磨损量建立函数关系,进而得到了不同切削角度下的摩擦效应力模型;最后通过引入单自由度斜体碰撞模型,采用等效弹簧阻尼法和霍普金森实验得到了冲击力模型。结合剪切力模型、摩擦效应力模型与冲击力模型得到了考虑后刀面磨损的拼接过缝处铣削力模型,最后对多硬度淬硬钢进行了铣削力实验。实验结果表明预测的铣削力幅值和变化趋势与实验值具有很好的一致性,验证了该铣削力建模方法的有效性,对拼接模具铣削加工工艺优化具有一定的理论指导意义。

In order to solve the problem of the change of milling force caused by tool wear in the milling process of splicing die,a modeling method of milling force considering the rear face wear of ball end cutter was put forward.According to the different hardness of the material,the cutting thickness of each cutting cycle was established as a function of the cutting angle,and the shear force model under different cutting angle was obtained.At the same time,the functional relationship between the friction effect stress of the rear face and the wear amount of the rear face was established,and the friction effect stress model under different cutting angles was obtained.The impact force model was obtained by introducing the single-degree-of-freedom italic collision model,using the equivalent spring damping method and Hopkinson experiment.Combined with the shear force model,friction stress model and impact force model,the milling force model at the splicing slit considering rear face wear was obtained.Finally,the milling force experiment of multi-hardness hardened steel was carried out.It was shown by the experimental results that the predicted milling force amplitude and variation trend are in good agreement with the experimental values,which verifies the effectiveness of the milling force modeling method,and has a certain theoretical guiding significance for the optimization of milling process of splicing die.