基于低温微量润滑与超声椭圆振动复合切削表面完整性形成机理研究

Facing the requirements of ultra-precision machining on the high surface integrity of pure iron high plastic material for the detonation physics of significant scientific experiments, but there is a serious problem of plastic deformation on the surface of pure iron materials cutting by the traditional precision machining process, so a novel ultra-precision machining process of ultrasonic elliptical vibration-assisted cutting composite with cryogenic minimum quantity lubrication (CMQL) for pure iron high-plastic materials was proposed. Firstly, through the study of the thermal-mechanical coupling mechanism and friction-reducing mechanism on the solid-liquid surface during CMQL and ultrasonic elliptical vibration assisted composite cutting, the mechanism of the cutting process in the composite cutting process of high-plasticity materials was revealed. Secondly, the macroscopic plastic flow behavior of the surface material under the action of composite cutting, the fracture characteristics of the chip microstructure, and the geometrical formation characteristics and physical changes of the machined surface were studied, and then the removal mechanism and surface integrity evolutionary mechanism of the high plasticity material under the combined cutting action were explored. Finally, by establishing a prediction model of surface integrity based on ultrasonic elliptical vibration-assisted cutting composite with CMQL, the composite cutting process multiple parameters and multi-objective surface integrity are coordinated and optimized. The results will provide theoretical and technical support for the surface integrity of high plastic materials by ultra-precision cutting, which also has the important engineering value for improving the accuracy and reliability of the precision physics experiments.

面向爆轰物理等重大科学实验对纯铁类高塑性材料高表面完整性的超精密加工需求，针对传统精密切削纯铁材料过程中表面存在严重的塑性变形问题，提出基于低温微量润滑与超声椭圆振动辅助复合切削纯铁类高塑性材料的超精密加工工艺新方法。首先，通过研究低温微量润滑与超声椭圆振动辅助复合切削过程固-液表面的力热耦合作用机制与减摩润滑作用机制，揭示高塑性材料复合切削过程中切削过程作用机理；其次，研究复合切削作用下表层材料的塑性宏观流动行为、切屑微观组织的断裂特征以及已加工表面几何形成特征与物理变化规律，进而探明复合切削作用下高塑性材料去除机理与表面完整性演化机制；最后，通过建立基于低温微量润滑与椭圆振动复合切削表面完整性预测模型，实现复合切削工艺多因素与表面完整性多目标的协同优化控制。研究成果将为高塑性材料的超精密切削表面完整性提供理论和技术支持，对于提高精密物理试验的置信度和可靠性具有重要的工程价值。

本项目面向爆轰物理等重大科学实验对纯铁类高塑性材料高表面完整性的超精密加工需求，针对传统精密切削纯铁材料过程中表面存在严重的塑性变形问题，提出了基于低温微量润滑和超声椭圆振动辅助复合切削纯铁类高塑性材料的超精密加工工艺新方法。本项目首先建立了低温MQL与超声椭圆振动复合作用下物理仿真模型和刀具-切屑的摩擦模型，揭示了复合切削过程固-液表面的力热耦合作用机制。然后建立了低温MQL与超声椭圆振动复合作用下有限元模型，并进行计算验证了超声振动切削和低温MQL复合技术可以有效减小切削力和降低切削温度，揭示了低温与微量润滑液在超声椭圆振动切削过程中的减摩润滑作用机制。从理论上分析了椭圆振动切削表面形貌形成机理，建立了振动切削表面粗糙度三维仿真模型；建立了超声椭圆振动切削残余应力预测模型，分析了椭圆振动已加工表面残余应力的形成机制，在此基础上研究了椭圆振动工艺参数对表面残余应力的预测与试验验证影响。最后采用低温MQL与超声椭圆振动复合切削优化工艺技术作为精密物理实验样品的最终高精度曲面轮廓精度保障技术，制造出了满足精密物理实验制造工艺需求的样品，保证了物理实验过程数值模拟的置信度和可靠性，本项目的研究成果具有重大的工程应用价值。