基于辐射声压的微细刀具超声振动表征方法

Characterization method for ultrasonic vibration of micro tools in ultrasonic machining based on radiated acoustic pressure

将超声振动叠加在微细刀具上进行小结构件的精密加工是超声加工的典型应用。刀具的超声参数是影响超声加工结果的重要因素,通常需要在加工前对其状态进行测量。但由于刀具几何形状的复杂性,目前还没有合适的方法对微细刀具的超声振动状态进行直接或间接表征。为解决此问题,基于辐射声压提出了一种微细刀具超声振动状态的表征方法,理论研究了刀具超声振动参数与其辐射声压之间的关系,分析了在不同测量条件下声压测量值与理想刀具辐射声压的差异。测量了不同形状微细刀具辐射的声压分布,提出了表征微细刀具超声振动的声压测量策略,并根据此策略搭建了实验平台,结果实现了对不同直径(0.1~0.9 mm)微细麻花钻工作频率的准确识别和对刀具振动相对幅值的定量描述。结果说明基于辐射声压的表征方法可以在低成本和高适应性条件下实现对微细刀具超声振动状态的在位表征。

It is a typical application of ultrasonic machining to superimpose ultrasonic vibration on micro tools for precision machining of small structural parts.In ultrasonic-assisted machining,the ultrasonic vibration of the tool is an important parameter that affects the machining quality.However,due to their micro diameter,measuring directly or indirectly the ultrasonic vibration of micro-tools with complex geometry by using the exist method poses a current challenge.To solve the problem,an acoustic characterization method for the micro-tool's ultrasonic vibration is proposed.The relationship between the tool ultrasonic vibration and the radiated sound pressure is studied theoretically.Additionally,the differences between the measured sound pressure under different measuring conditions and the ideal sound pressure radiated by the tool are analyzed,and the sound pressure distribution radiated by different micro-tools is measured.Then a sound pressure measurement strategy is proposed and the corresponding experiment platform is established to characterize the ultrasonic vibration of the micro-tool.By using the acoustical measurement strategy,the working frequency of micro twist drill with different diameters(0.1~0.9 mm)is identified and the relative amplitude of tool vibration is quantified.The method based on radiative sound pressure can be used to in situ characterize the ultrasonic vibration state of micro-tools at low cost and high adaptability,which supplies a fundamental tool for the ultrasonic-assisted micro-machining process study.