Cutting high-performance materials with ultrasonically modulated cutting speed
Cutting high-performance materials with ultrasonically modulated cutting speed
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DOI：
10.1117/12.2565757
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发表时间：
2020-07
期刊：
影响因子：
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通讯作者：
Armin Reif;Sebastian Sitzberger;R. Rascher
中科院分区：
文献类型：
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作者：
Armin Reif;Sebastian Sitzberger;R. Rascher
轻量化结构的持续趋势和高达95%的相关加工率导致高性能材料的使用增加。对部件强度和质量的要求不断提高，以及相关材料的使用难以加工，需要进一步开发新的经济加工技术。在超声辅助加工中，附加的高频振动叠加在传统的加工过程中。刀具的振动通常是轴向或纵向于工件激励的，即垂直于切削方向。围绕刀具的旋转轴（扭转）的附加振动叠加也是可能的。这在切削方向上产生振动叠加。振动引发导致在刀具切削刃处的几微米范围内的振幅。这又导致切削速度或进给速率的高频变化。总的来说，额外的扭转振动重叠可以进一步降低切削力，增加刀具寿命并提高工件质量。为了使磨削工具产生扭转振动，需要通过仿真设计特殊工具。扭转振动的形成是通过超声焊极中的螺旋槽实现的。取决于旋转角度和槽的长度，轴向振动的一部分通过超声波发生器的轴向激励被转换成扭转振动。设计槽的目的是实现尽可能高的振动幅度。在模拟之后，将槽插入到工具中的相应的最佳几何位置。然后，通过加工脆硬微晶玻璃材料Zerodur来验证专门设计的磨削工具。扭转振动工具的第一次测试结果如下所示。
The continuing trend towards lightweight construction and the associated machining rates of up to 95 % lead to an increased use of high-performance materials. The ever growing demands on the strength and quality of components and the associated use of materials which are hard to machine require the further development of new, economical machining techniques. In ultrasonic-assisted machining, an additional high-frequency vibration is superimposed on the conventional machining process. The vibration of the tool is usually excited axially or longitudinally to the workpiece, i.e. vertical to the cutting direction. An additional vibration overlay around the rotation axis (torsional) of the tool is also possible. This generates a vibration overlay in the cutting direction. The vibration initiation causes vibration amplitudes in the range of a few micrometers at the tool cutting edge. This leads in turn to a high-frequency change in the cutting speed or feed rate. Overall, an additional torsional vibration overlap can further reduce cutting forces, increase tool life and improve workpiece quality. In order for a grinding tool to generate a torsional vibration, a special tool was required that had to be designed by simulation. The formation of a torsional vibration was achieved by helical slots in the sonotrode. Depending on the angle of rotation and the length of the slots, a part of the axial vibration is converted into a torsional vibration by an axial excitation of the sonotrode. The aim in designing the slots was to achieve the highest possible vibration amplitude. Following the simulation, the slots were inserted into the tool in the corresponding optimum geometric position. Afterwards, the specially designed grinding tool was validated by machining the brittle-hard glass-ceramic material Zerodur. The first test results with the torsionally vibrating tool are presented in the following.