基于动力学不确定性的重型切削工艺参数优化

针对数控重型切削加工过程的切削稳定性具有不确定性的特点,提出了在切削稳定性和机床工作能力的约束下,获得最大材料去除率的工艺参数优化方法。根据重型切削加工的工艺特点建立三维动力学模型,以机床的固有频率、阻尼比、刚度和切削力系数作为不确定因素,结合排零定理和边理论对其进行不确定性分析,获得稳健的切削稳定性叶瓣图,结合切削深度、刀具直径和刀具齿数的关系,为加工过程选择能获得最大切削深度的刀具。在此基础上,建立工艺参数优化模型,选择最佳的轴向切削深度、径向切削深度和主轴转速的组合,最后以一台加工中心上某型号发动机缸体表面的粗加工过程为例进行了验证。

Optimization of Process Parameters for Heavy-Duty Milling Based on the Uncertainty of Cutting Dynamics

Considering the uncertainty of cutting dynamics, the optimization of heavy-duty milling parameters was presented to obtain the maximum material removal rate under the constraints of cutting stability and machine tool working capacity. The three-dimensional dynamic model was set up according to the property of the face milling cutter in heavy-duty milling, in which the natural frequency, damping ratio, machine tool stiffness, and cutting force coefficients were regarded as the uncertain factors. The zero-excluding theory and edge theory were used to analyze the uncertainty of obtaining a robust cutting stability lobes diagraph. Then, the cutting tool that could achieve maximum cutting depth was selected according to the relation of cutting depth, tool diameter, and number of teeth. Finally, the optimal model of process parameters selection was set up, and the optimal parameters of axial cutting depth, radial cutting depth, and spindle speed were selected. The results were verified with rough machining for a cylinder surface on a CNC machining center.