复杂薄壁件高效高精多轴加工的几何建模与工艺优化

Complex thin-walled parts are widely used in defense, energy and transportation industry, manufacturing level of which is the crucial index of judging the manufacturing capability of a nation. It is highly demanded to develop techniques of fabricating this kind of part with high accuracy and efficiency. Aim at issues hereinbefore, Starting from modeling geometry concerning process of five-axis machining, this research conduct the study of process modeling and optimization of machining complex thin-walled parts with high accuracy and efficiency. A precise model of swept volume formed by five-axis motion of cutters is set up on the base of the study to solving the boundary of curve family formed by intersecting moving cutter with parallel planes. A device is designed and fabricated to measure the deflection of thin-walled parts, meanwhile a FEM model is established and adjusted according measured and predicted deflection. Then a neural network system is trained to represent the deflection caused by cutting forces. After the dynamic geometric model of workpiece is established, the model of calculating engagement between workpiece and cutter is set up. Based on the geometric models established above, addressing the deflection over tolerance and lower cutting efficient, a optimal model of tool path for five-axis finishing milling and a optimal model of tool path for four-axis rough plunging are established respectively. By employing computing intelligent methods, multi-axis machining process of complex thin-walled parts with high accuracy and efficiency is achieved eventually. The research achievement could enrich and improve the CNC machining theory of complex thin-walled parts and further satisfy the needs of national major equipments.

复杂薄壁件广泛应用于国防、运输、能源等领域，其制造水平是衡量一个国家制造能力的重要标志，其高精高效加工是目前亟需解决的问题。针对以上难题，本研究从五轴加工过程的精确几何建模入手，开展复杂薄壁件高精高效工艺建模与优化研究。通过对刀具截面曲线族边界求解问题的研究，构建刀具五轴运动扫掠体的精确模型和快速求解方法。通过建立复杂薄壁件工艺刚度测量方法，并结合有限元方法与神经网络方法，实现薄壁件挠度的快速计算。构建加工过程中工件的动态几何模型，建立五轴运动中刀具工件动态啮合关系的精确模型。在上述几何模型的基础上，针对复杂薄壁件加工变形大、加工效率低问题，分别建立五轴点铣精加工路径优化模型、以及高效率四轴插铣刀具路径优化模型，结合计算智能优化求解方法，最终形成复杂薄壁件高效高精多轴数控加工工艺方法。丰富和完善了复杂薄壁件多轴数控加工理论，满足我国重大装备对复杂薄壁件多轴加工技术的需求。

复杂薄壁件广泛应用于航空、国防、运输和能源等领域，其制造水平是衡量一个国家制造能力的重要标志。高精高效加工复杂薄壁件是智能制造的核心技术。本基金项目的目的是高精高效加工复杂薄壁件。它的内容包括（1）五轴加工中刀具扫掠体精确建模和快速求解方法；（2）刀具与工件动态啮合关系的精确建模；（3）复杂薄壁件数控加工的工艺优化；（4）复杂薄壁件高效率四轴插铣优化方法。在本基金项目支持下，项目负责人和其合作者对复杂薄壁零件多轴数控加工中的几何学和工艺学进行了深入的研究，取得了三项原创性的重要成果，对复杂薄壁零件的多轴数控加工的学术研究做出了实质性的贡献，也为工业界高精高效加工复杂薄壁零件提供了核心技术。这些成果总结如下。.原创性地提出了一套快速精确地建立五轴加工中瞬时未变形切屑模型的方法。该方法彻底地解决了传统的未变形切屑建模方法计算时间长和模型精度低的缺点。该方法可以有效地实现五轴数控加工复杂薄壁零件的几何仿真和物理仿真。从而优化切削参数保证被加工零件表面的精度和零件的加工效率。该成果发表在国际一流期刊Computer-Aided Design上，得到了学术界和工业界专家的高度评价。.成功地开发了一套优化细长薄壁空心轴的加工工艺的方法。通过建立准确的刀具实体模型，将该刀具模型应用到切削力预测中，提高了切削力预测的精度。通过建立该轴的过程模型，将切削力准确地加载在该轴模型上，利用有限元分析的方法计算出该轴的瞬时回弹量。通过优化切削参数，保证该轴在加工时的回弹量不超过它的公差。该技术已经成功地应用在中航发公司，使该公司的智能制造技术有实质性的提高。.有效地提出了一个优化多轴插铣开式叶盘的插刀路径的方法。该方法可以自动计算插刀的位置和方向，保证尽可能少的叶片余量，同时插刀不干涉叶盘的叶片。该方法已经通过了实验室的多次验证，效果非常满意。它可以直接应用于航空发动机企业，提高叶盘的生产效率。