Effects of machine component damping on dynamic behaviour and process stability of machine tools

机床的精度和性能取决于切削过程和机床结构的动态顺应性之间的相互作用。颤振可能是由于刚度或阻尼不足引起的大的动态顺应而产生的。这些自激振动限制了机床性能，导致工件表面质量变差，降低了刀具寿命。为了在开发过程中计算和优化机床的动态性能，必须了解力流中所有结构部件和关节的刚度、质量和阻尼。虽然质量和刚度值通常是已知的，但经过验证和参数化的精确阻尼模型仍然缺失。为了减少这些缺陷，德国研究基金会资助了“机床中的阻尼效应”研究小组。在子项目“机床部件阻尼效应测量方法”中，亚琛工业大学机床实验室（WZL）开发了方法基础，用于参数化机床部件的阻尼模型。在这里，不同的设计变量和不同的润滑对部件的阻尼有显著的影响。在本项目中，可重复确定阻尼的方法和关于进给轴部件阻尼效应的知识将用于改善机床的动态性能。为此目的，将检查应用伙伴的两种不同的机床，加工中心和车床。这两台机器的进给轴部件的阻尼特性将在试验台的帮助下确定。基于对阻尼效应的了解，对机器部件进行选择性修改。例如，单轨制导系统可以被不同的设计变体所取代，以确保整个机床的动态性能得到改善。将测量改进后的机床的动态行为，从而研究是否可以通过简单的部件修改来操纵机床的动态顺应性和过程稳定性。

The accuracy and performance of machine tools are determined by the interaction between the cutting process and the dynamic compliance of the machine structure. Chatter vibrations may occur due to large dynamic compliances which are caused by insufficient stiffness or damping. These self-excited vibrations limit the machine performance, cause a bad surface quality of the workpiece and reduce tool life. In order to calculate and optimize the dynamic behavior of a machine tool in the development process, knowledge of stiffness, mass and damping of all structural components and joints lying in the force flux is necessary. While mass and stiffness values are usually well known, validated and parameterized accurate damping models are still missing. In order to reduce these deficits, the research group "Damping effects in machine tools" is being funded by the German Research Foundation. Within the subproject "Methods for the measurement of damping effects in machine components" methodological foundations were developed by the Laboratory for Machine Tools (WZL), RWTH Aachen, for parameterizing damping models of machine tool components. Here, a significant influence of different design variants and various lubrications were detected on the damping of components. In this project, the method to repeatable determine damping and the knowledge about damping effects of feed axis components will be used to improve the dynamic behavior of machine tools. For this purpose two different machine tools of the application partners will be examined, a machining center and a lathe. The damping behavior of the feed axis components of both machines will be determined with the help of test benches. Based on the knowledge of the damping effects, machine components will be selectively modified. For example, the monorail guidance system might be replaced by different design variants which ensure an improvement of the dynamic behavior of the entire machine tool. The dynamic behavior of the modified machine tool will be measured and as a result it will be investigated whether the dynamic compliance and the process stability of the machine tool can be manipulated by the simple modification of components.