超声横向激励下轴向运动金刚石线锯振动切割分析

金刚石线锯由于切缝窄、柔性好而广泛应用于Si、SiC等超硬脆材料的切割过程中，而超声振动在硬脆材料加工方面具有独特的优势。将超声振动应用于线锯切割过程中，在分析轴向运动弦线振动模型的基础上，利用变量分离求解出线锯在两种不同位置超声激励下横向受迫振动位移场的函数表达式以及线锯系统自然频率的函数表达式；研究讨论了线锯系统的参数对固有频率的影响；分析了线锯临界速度以及线锯往复切割时线锯中点振幅与超声激振线锯系统参数的关系；提出了工件进给速度是影响超声振动线锯切割模式的决定因素。用多普勒激光测振仪对线锯的固有频率、线锯超声激励频率和在振动切割SiC中线锯不同点处的频率进行测定，并对线锯施加超声和不施加超声切割SiC进行了对比实验。结果表明超声振动切割能减小23%～38%的切割力，能明显改善切割表面的质量。测定和实验结果与模型分析有较好的一致性。

Vibration Cutting Analysis of Axially Moving Diamond Wire Saw Excited by Transverse Ultrasonic Wave

The diamond wire saw has been widely used in cutting the hard and brittle materials, such as Si and SiC single crystals, because of its narrow kerf and great flexibility. The ultrasonic vibration has a unique benefit in cutting the ultra-hard and brittle materials. Based on the analysis of vibration model of axially moving string, the expressions of transverse vibration displacement field in which the wire saw is excited in different positions by ultrasonic wave are solved by applying the separation-of-variables method, and the expression of system natural frequency is obtained, too. The effect of wire saw system parameters on natural frequency is discussed. The critical speed of wire saw is analyzed. The relation among the midpoint amplitude of wire saw excited by ultrasonic wave when wire saw reciprocatedly cuts and the parameters of wire saw system is analyzed. It is proposed that the feed speed of workpiece is a decisive factor affecting cutting mode of wire saw excited by ultrasonic wave. Doppler laser vibrometer is used to measure the natural frequency of wire saw, the vibration response frequency of wire saw excited by ultrasonic wave, and the frequencies of wire saw in different positions when wire saw cuts SiC ingot with ultrasonic vibration. Comparative experiments of cutting SiC are carried out with and without ultrasonic vibration.The result shows that cutting forces is reduced by 23%～38% with ultrasonic vibration cutting, and the quality of the cut surface is improved obviously. The measurement and experimental results are consistent with the analysis results of model.