加跟刀架的细长轴车削加工尺寸误差的仿真

为探索跟刀架的作用机理,开发了一个联合模型用以仿真细长轴车削尺寸误差的形成过程。该模型由3部分组成:切削力统计模型、工件变形模型及尺寸误差的几何分析。值得注意的是,切削力与实际切削深度间存在耦合效应,因此切削力不能直接求得,这里采用二分法进行迭代运算来解决此问题。最后,通过一系列试验对仿真模型进行验证,结果表明仿真值与实测值比较一致。由仿真结果可知,跟刀架刚度对细长轴中部尺寸误差的影响最显著,而降低这个部位的尺寸误差也是细长轴车削的难点所在,因此,改进跟刀架结构是提高尺寸精度的有效途径。本文的主要贡献是在建立跟刀架的力学模型的基础上分析了影响细长轴车削尺寸误差的主要因素。

Simulation of Diameter Error During Turning Slender Bar Supported by Follower Rest

To explore the mechanism of the follower rest,a united model is developed to simulate the formation of the diameter error of the slender bar.The model consists of three parts: an empirical model for the cutting force,a model for the workpiece deflection and the geometric analysis of the diameter error.It is noted that the cutting force cannot be directly calculated due to the presence of coupling between the cutting force and the actual depth of the cut.To solve this problem,the dichotomy is used to determine the coupled cutting force.Finally,a series of experiments are conducted to verify the simulation model.And the good agreement between numerical and experimental results is acquired.Simulation values show that the stiffness of the follower rest is the most significant influencing factor of the dimensional accuracy at the middle section of the slender bar.Since the most difficult task lies in the reduction of the diameter error at the middle section,efforts should be made to improve the structure of the follower rest.The primary originality is to develop a mechanical model of the follower rest and to investigate the main influencing factors of the diameter error of slender bars.