多点变约束下硬旋铣大型螺纹的动态响应与表面粗糙度研究

发布时间：2018-11-10 13:04

【摘要】：大型螺纹硬态旋风铣削加工技术具有工件多点变浮动支撑约束、随动抱紧装置动态夹持、铣刀盘超长距离移动、多刀具周期性断续渐进成型切削等特点,使得螺纹工件系统动态响应、切削特性以及螺纹滚道表面粗糙度等,都与普通切削方式有着明显区别。为实现对大型螺纹硬旋铣过程的优化控制和进一步提高大型螺纹全长的加工质量,本课题以大型螺纹数控旋风铣床为研究对象,分别从工件系统动态响应以及螺纹滚道表面粗糙度方面进行研究。首先开展了大型螺纹硬旋铣工艺参数试验,对切削力、振动和螺纹滚道表面轮廓形貌进行了分析,然后提取了其相应的特征值,研究了各主要切削工艺参数和多点变支撑装夹约束对铣削工件系统的动态响应和螺纹滚道表面粗糙度的影响规律以及影响程度,提出了优化的切削工艺参数组合。其次依据瑞利梁理论和模态形函数法建立了硬旋铣大型螺纹工件系统动力学模型,并考虑到螺纹工件自转、卡盘-顶尖边界条件和切削力沿轴向移动的特点,研究了浮动支撑个数、间隔距离以及随动抱紧装置抱紧刚度对切削点处动态响应的影响和多点变约束下螺纹全长的动态响应,进而优化多点变浮动支撑装夹约束条件,进一步提高硬旋铣大型螺纹全长的加工质量。最后采用回归方法和BP神经网络方法建立了基于工艺参数的表面粗糙度和振动预测模型,从而实现对大型螺纹硬旋铣过程中的表面粗糙度和振动的优化控制,有助于指导实际生产,减少废品的出现,提高经济效益。
[Abstract]:The technology of heavy thread hard state whirlwind milling is characterized by multi-point variable floating support constraint of workpiece, dynamic clamping of follower and clamping device, super-long distance movement of milling cutter disc, periodic incremental cutting of multi-cutting tools, and so on. The dynamic response of the thread workpiece system, cutting characteristics and surface roughness of the thread raceway are obviously different from the common cutting methods. In order to realize the optimization control of large screw thread hard rotary milling process and further improve the processing quality of large thread length, this subject takes the large-scale thread numerical control whirlwind milling machine as the research object. The dynamic response of the workpiece system and the surface roughness of the thread raceway are studied respectively. In this paper, the cutting force, vibration and surface profile of the thread raceway are analyzed, and the corresponding characteristic values are extracted. The effects of main cutting parameters and multi-point variable support clamping constraints on the dynamic response of milling workpiece system and the surface roughness of thread raceway are studied. The optimized cutting process parameter combination is proposed. Secondly, according to Rayleigh beam theory and modal shape function method, the dynamic model of hard rotary milling large-scale screw parts is established, and the characteristics of rotation of thread workpiece, chuck center boundary condition and cutting force moving along axial direction are considered. The effects of the number of floating support, the distance between the floating support and the clamping stiffness of the follower on the dynamic response at the cutting point and the dynamic response of the thread length under the multi-point variable constraint are studied, and the constraint conditions of the multi-point variable floating support clamping are optimized. Further improve the machining quality of the full length of hard rotary milling large thread. Finally, a prediction model of surface roughness and vibration based on process parameters is established by using regression method and BP neural network method, which realizes the optimal control of surface roughness and vibration in the process of hard rotary milling of large screw threads. It is helpful to guide actual production, reduce the appearance of waste products and improve economic efficiency.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG62

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