基于外圆车削加工机理的轻合金表面形貌研究

Study on Surface Morphology of Light Alloy Based on External Cylindrical Turning Mechanism

摘要:

构建轻合金车削表面形貌预测模型，对于提高车削参数优化效率和零件表面质量具有重要意义。首先，基于外圆车削加工机理，考虑刀具几何结构尺寸、机床振动和切削加工弹塑性变形对加工表面形貌的影响，建立工件表面形貌仿真模型，并进行切削实验验证；然后，采用三维表面粗糙度算术平均高度 Sa、均方根高度 Sq表征表面形貌，对比仿真与实验所获得的表面形貌和表面粗糙度；最后，以切削效率和表面粗糙度为优化目标，采用非支配排序遗传算法（NSGA-Ⅱ）优化切削参数，获得切削参数非支配解集。结果表明：在不同切削参数下波峰高度变化趋势基本一致，Sa的平均相对误差为 3.95%，Sq的平均相对误差为 8.34%，说明模型较为准确，具有较好的预测效果，能反映工件的表面质量。

Abstract:

The construction of the prediction model of light alloy turning surface morphology is of great significance for the optimization of turning parameters and the improvement of part surface quality. Based on the mechanism of cylindrical turning, the simulation model of workpiece surface topography is established considering the influence of tool geometry, machine vibration and cutting elastoplastic deformation.Cutting experiments were conducted to verify and compare the surface morphology obtained from simulation and experiments.The trend of peak height variation tended to be consistent under different cutting parameters;Three-dimensional surface roughness arithmetic mean height Sa and root mean square height Sq are used to characterize the surface topography. The average relative error of Sa is 3.95% and the average relative error of Sq is 8.34%,,indicating that the model is accurate and has good prediction effect, and can reflect the surface quality of the workpiece.Finally, with cutting efficiency and surface roughness as optimization objectives,the cutting parameters were optimized using Non-Dominated Sorting Genetic Algorithm II (NSGA-II), and the non-dominated solution set of cutting parameters was obtained for reference by decision makers.