Fundamentals of material-specific process damping on rounded and worn cutting edges

圆形和磨损切削刃上特定材料工艺阻尼的基础知识

• 批准号: 493837624
• 负责人: Professor Dr.-Ing. Berend Denkena
• 金额: --
• 依托单位: Institut für Fertigungstechnik und Werkzeugmaschinen (IFW)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/493837624?language=en
• 关键词: Fundamentals; material; specific; process; damping

Self-excited vibrations, so-called chatter vibrations, are often a limiting factor when the productivity of machining processes is increased. However, chatter vibrations can be suppressed by increasing the contact of the flank face with the material, since oscillation movements into the material are damped by the springback of the material. This effect is called process damping. A further method of avoiding chatter vibrations is the simulative prediction of suitable process parameters, in which chatter vibrations are avoided. However, taking the process damping effect into account within simulative models is associated with high inaccuracies. This is due to the fact that the existing process damping models do not adequately reflect the highly complex elastic-plastic deformation processes below the flank face. The damping force acting on the flank face is often modelled as the product of a constant process damping coefficient and the volume indented under the flank face. Some preliminary work shows that the process damping coefficient depends on the rounding of the cutting edge and the clearance angle. This can be attributed to thermal effects and the neglect of plastic deformations within the model. However, the exact relationship between tool geometry, the elastic-plastic material behaviour below the clearance and the process damping force is unknown. Therefore, the aim of the project is to obtain a fundamental understanding of the material- and geometry-dependent process damping on the basis of the elastic-plastic material behaviour during the flank-face contact. In order to achieve this goal, the contact conditions at the cutting edge for different cutting edge rounding and wear conditions are analysed in orthogonal cutting test by high-speed images and force measurements. Based on the experimental results a new process damping model will be developed, which will be implemented in a material removal simulation of the milling process to predict the dynamic tool behaviour.

自激振动，即所谓的颤振，通常是提高加工过程生产率时的一个限制因素。然而，可以通过增加后刀面与材料的接触来抑制颤振振动，因为进入材料的振动运动被材料的回弹所抑制。这种效应称为过程衰减。另一种避免颤振的方法是对合适的工艺参数进行模拟预测，从而避免颤振。然而，在模拟模型中考虑过程阻尼效应会带来很高的误差。这是由于现有的过程阻尼模型不能很好地反映后刀面下高度复杂的弹塑性变形过程。作用在后刀面上的阻尼力通常被建模为恒定的工艺阻尼系数与后刀面压痕体积的乘积。初步研究表明，加工过程的减振系数取决于刀具刃口的圆度和间隙角度。这可以归因于热效应和忽略了模型中的塑性变形。然而，刀具几何形状、间隙以下的弹塑性材料行为和工艺阻尼力之间的确切关系尚不清楚。因此，该项目的目的是根据弹塑性材料在翼面接触过程中的行为，对材料和几何相关的过程阻尼有一个基本的了解。为了达到这一目的，通过高速图像和测力分析了不同刀具刃口圆角和磨损条件下的刀具刃口接触条件。在实验结果的基础上，建立了一个新的过程阻尼模型，该模型将应用于铣削过程的材料去除模拟，以预测动态刀具行为。