真空预载液体静压支撑的薄壁件镜像铣削加工精度和表面质量研究

High quality and high efficiency machining of thin-wall, low-stiffness and large-scale skin parts with complex curved surface is in great demand in the aerospace field. Mirror milling is an efficient and green processing technology for large-scale skin parts. The support technology of mirror milling is the key technology to ensure the machining accuracy and surface quality. Aiming at the problems of poor machining accuracy and surface quality, as well as the scratches on the support surface in the sliding and rolling support modes, a new technology of vacuum preloading hydrostatic support is proposed. The machining accuracy and surface quality of thin-wall parts by mirror milling with vacuum preloaded hydrostatic support are systematically studied. The vacuum preloaded hydrostatic support system is designed and developed by studying the mechanical properties and stability of the support system. The milling force and machining deformation under vacuum preloaded hydrostatic support are studied. The influence rules of the support system and milling process parameters on the machining accuracy and surface quality are analyzed. The surface topography and roughness prediction model of thin-wall parts by mirror milling are established. According to the bending characteristics of skin surface, the matching relationship of “workpiece-tool-support-process parameters” is studied, and reasonable support system and milling process parameters are determined. The project will provide theoretical and technical support for the research and development of mirror milling technology and equipment, which achieves high quality and high efficiency mirror milling of aircraft skins.

复杂曲面、薄壁低刚度大型蒙皮零件的高质高效加工是航空航天领域的重大需求。镜像铣削技术是大型蒙皮零件的一种高效、绿色加工新技术。镜像铣削的支撑技术是保证铣削加工精度和表面质量的关键技术。本项目针对目前镜像铣削采用滑动、滚动支撑存在加工精度和表面质量差、支撑表面容易产生划痕等问题，提出真空预载液体静压支撑新技术，系统研究采用真空预载液体静压支撑的薄壁件镜像铣削加工精度和表面质量。通过研究支撑系统的力学特性和稳定性，设计和开发真空预载液体静压支撑系统；研究真空预载液体静压支撑下的铣削力和加工变形，分析支撑系统和铣削工艺参数对加工精度和表面质量的影响规律，建立薄壁件镜像铣削表面轮廓和粗糙度预测模型；针对蒙皮曲面特征，研究“工件-刀具-支撑-工艺参数”之间的匹配关系，确立合理的支撑系统参数和铣削工艺参数。项目研究将为研发蒙皮镜像铣削技术和装备，实现飞机蒙皮镜像铣削的高质高效加工提供理论和技术支持。

面向航空航天领域对复杂曲面、薄壁低刚度大型蒙皮零件的高质高效加工的重大需求，本项目针对目前镜像铣削采用滑动、滚动支撑存在加工精度和表面质量差、支撑表面容易产生划痕等问题，提出了真空预载液体静压支撑新技术，系统研究了采用真空预载液体静压支撑的薄壁件镜像铣削加工精度和表面质量。通过研究支撑系统的力学特性和稳定性，设计并开发了真空预载液体静压支撑系统；研究了真空预载液体静压支撑下的铣削力和加工变形，分析了支撑系统和铣削工艺参数对加工精度和表面质量的影响规律，建立了薄壁件镜像铣削表面轮廓和粗糙度预测模型；针对蒙皮曲面特征，建立了“工件-刀具-支撑-工艺参数”之间的匹配关系，确立了合理的支撑系统参数和铣削工艺参数，选择液膜刚度最大时对应的进液压力和较大的真空负载可以得到更好的工件厚度一致性，厚度方差≤0.5×10-5 mm2。选择较大的每齿进给量、较大的径向切深、较小的轴向切深、较小的刀尖圆弧半径可以得到较小的表面粗糙度，加工表面粗糙度Ra≤0.5μm。项目研究为研发蒙皮镜像铣削技术和装备，实现飞机蒙皮镜像铣削的高质高效加工提供了理论和技术支持。