车铣复合加工中心床身动态特性分析和优化设计

发布时间：2018-06-26 18:49

本文选题：CK6140车铣复合加工中心 + 床身　；参考：《济南大学》2017年硕士论文

【摘要】：高效切削加工技术的发展使得切削速度不断提高,对加工中心的复合功能也提出了新要求,评价加工中心优劣的指标不在局限于机床的静态特性,而是重点评价能够决定加工精度、工件表面质量、生产效率以及刀具使用寿命的机床动态特性,对切削加工系统的动态特性研究已经成为高档数控机床研发制造的关键共性技术问题。本文对CK6140车铣复合加工中心的床身进行了模态分析。利用Workbench有限元仿真软件对床身进行模态仿真,数值计算求解床身结构的前三十阶固有频率,得到十三阶模态的数值模态参数;采用单输入多输出的SIMO锤击法进行了数据采集工作,运用Matlab编制的最小二乘复指数法程序对基于采集数据的频响函数进行拟合和模态参数识别,得到了床身结构前十三阶的试验模态参数;通过试验结果与仿真数值计算结果对比验证了仿真数值计算的正确性。对CK6140车铣复合加工中心的床身进行了动态特性分析。分析了铣削加工时的切削力,利用Workbench有限元仿真软件对床身变形、床身谐响应进行了分析,发现第一阶模态到第三阶模态的固有频率与谐响应分析的共振峰频率基本重合,说明了床身结构对于低阶模态,尤其是第一阶模态非常敏感,假如工作频率接近低阶模态频率,就会产生剧烈的共振现象。对CK6140车铣复合加工中心的床身结构进行了优化设计。利用吉村允孝积分法建立了阻尼块与床身型腔间机械结合面的等效动力学模型,以阻尼块的属性、数量为设计变量,以降低实际工况下床身的最大动力响应幅值及改善低阶模态固有频率为优化目标,确定合理的优化参数,提出基于附加阻尼方法的床身动态优化方案。通过分析方案,床身的动态特性得到了显著的改善。
[Abstract]:With the development of high efficiency machining technology, the cutting speed is increasing, and the new requirements for the complex function of machining center are put forward. The evaluation index of machining center is not limited to the static characteristic of machine tool. It focuses on evaluating the dynamic characteristics of machine tools that can determine machining accuracy, workpiece surface quality, production efficiency and tool life. The research on the dynamic characteristics of cutting system has become a key common technical problem in the research and manufacture of high grade NC machine tools. Modal analysis of the bed of CK6140 turn-milling complex machining center is carried out in this paper. The first 30 natural frequencies of the bed structure are numerically calculated and the numerical modal parameters of the thirteenth mode are obtained by using the Workbench finite element simulation software. The single input multiple output Simo hammering method is used to collect data. The frequency response function based on the collected data is fitted and modal parameters are identified by using the program of least square complex exponent developed by Matlab. The experimental modal parameters of the first thirteenth order of the bed structure are obtained, and the correctness of the simulation numerical calculation is verified by comparing the experimental results with the simulation results. The dynamic characteristics of the bed of CK6140 turn-milling complex machining center are analyzed. The cutting force during milling is analyzed, and the deformation and harmonic response of the bed are analyzed by using the Workbench finite element simulation software. It is found that the natural frequencies from the first to the third modes basically coincide with the resonance peak frequencies of the harmonic response analysis. It is shown that the bed structure is very sensitive to the low-order modes, especially the first-order modes. If the operating frequency is close to the low-order modal frequency, there will be a violent resonance phenomenon. The bed structure of CK6140 turn-milling complex machining center was optimized. An equivalent dynamic model of the mechanical interface between the damping block and the bed cavity is established by using the Yoshimura Yunxiao integration method. The attribute and quantity of the damping block are taken as the design variables. In order to reduce the maximum dynamic response amplitude of the bed under actual working conditions and improve the natural frequency of the low-order mode as the optimization objective, the reasonable optimization parameters are determined, and the dynamic optimization scheme based on the additional damping method is proposed. By analyzing the scheme, the dynamic characteristics of the bed are greatly improved.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG65

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