数控铣削过程中工件的振动测试及分析

Testing and analysis on the work-piece vibration in numerical control milling process

利用振动信号分析仪及加速度传感器,通过锤击法得到了加工系统在铣削前后的固有频率;测试了数控铣床在不同主轴转速的铣削过程中工件的振动响应,得到了工件振动加速度信号的时域曲线及自功率谱密度曲线.研究表明:1)随着主轴转速的降低,工件振动的自功率谱密度值减小,铣削振动的最大能量是最小值的4.3倍;2)随着主轴转速的降低,工件高频振动的时间缩短,当转速降低到某一值时高频振动消失.铣削过程中工件振动的最高频率是最低频率的11.7倍.

By the vibration signal analyzer and the acceleration sensor,the natural frequency of the machining system before milling has been obtained by the hammering method,and the vibration responses of the work-piece in the milling process with different rotational speeds are tested on numerical control milling machine.Moreover,the time domain curves and the self-power spectral density curves of the acceleration signals of the work-piece vibration are obtained.The study indicates that：1） with the decrease in rotational speed,the self-power spectral density of the work-piece vibration decreases and the maximum vibration energy in milling process is four times of the minimum value;2） with the decrease in rotational speed,the time of high-frequency vibration of the work-piece reduces and the high-frequency will disappear when rotational speed reduces to a certain value.By the tests,the maximum frequency of the work-piece in the milling process is twelve times of the minimum one.