慢刀伺服变主轴转速车削非圆截面元件研究

Research on Variable Spindle Speed in Slow Tool Servo Turning of Noncircular Section Components

超精密非圆截面元件,如质谱仪中的双曲面四极杆,通常采用慢刀伺服(slow tool servo,STS)车削的方法加工。然而,由于STS的带宽较低,使得STS跟踪目标刀具轨迹的能力在一定程度上受到限制,导致被加工零件轮廓产生较大的形状误差。为了降低该误差,作者提出一种基于STS的变主轴转速(variable spindle speed,VSS)车削非圆截面元件的加工方法。阐述了如何根据非圆截面元件轮廓设计出相应主轴转速的变化轨迹。为验证所提方法的正确性,利用STS以主轴定转速和变转速方式分别车削了截面轮廓呈正弦变化的零件,并对刀具伺服输入信号进行了频谱分析。实验结果显示:变主轴转速车削正弦截面零件的形状误差小于定主轴转速车削。结果表明:所提出的VSS加工方法能够有效地提高车削非圆截面零件的形状精度。

Ultra-precision noncireular section components, such as hyperbolic quadrupole in mass spectrometer, can be machined by diamond turning assisted by slow tool servo （STS）. HOwever, the bandwidth of STS is usually small,which limits the STS＇ s capability in fol- lowing the required tool path,leading to a large form error, To reduce the form error,an approach was proposed to apply variable spindle speed （VSS） to STS-based turning. The designing of the VSS trajectory based on the noncircular profile of the optical component was presented. To validate the proposed approach,the experiment on the application of VSS in the STS-based turning process was conducted to machine a typical noncircular component which has a sinusoidal-wave along peripheral direction. The input signals which actuate the tool servo were also analyzed by using FFT to obtain their frequency spectrum. Experiments results showed that the form error of the noncireular component in VSS way is less than that machined in CSS way. Therefore the proposed approach is effective increasing a higher form accuracy of the machined noncircular optical components.