Evaluation of on-machine measuring method for dynamic stiffness of thin-walled workpieces
Evaluation of on-machine measuring method for dynamic stiffness of thin-walled workpieces
复制标题
薄壁工件动态刚度在机测量方法评价
DOI：
10.1016/j.procir.2018.08.204
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Matsubara Atsushi
中科院分区：
文献类型：
--
作者：
Umezu Takuma;Kono Daisuke;Matsubara Atsushi
由于薄壁零件在加工过程中产生的静态和动态位移，其加工一直是人们研究的热点问题。加工条件的设定要充分考虑到工件的振动特性。自动在机系统可用于测量工件的动态硬度，从而实现可靠且频繁的测量。在这项研究中，评价了一种在机上测量工件动态刚度的装置。分析了冲击试验机上测量法与冲击试验法之间固有频率差异的原因。用Rayleigh-Ritz方法研究了振子和加速度计附加质量对固有频率的影响。进行了切割试验，以验证是否可以根据在机动刚度测量的测量结果来设置合适的切割条件。在机测量法与冲击试验法之间的固有频率差异是由压电致动器接触产生的附加质量引起的。当附加质量为当量质量的5%或更小时，固有频率差仅为10赫兹或更小。在使用足够大质量的工件进行的切割试验中，在机测量方法与冲击试验的一致性是可以比较的。当受迫振动较小时，通过在机动刚度的测量，可以准确地估计出稳定极限。
Machining of thin-walled workpieces is a popular issue due to its static and dynamic displacements during machining. It is required to set machining conditions sufficiently considering the vibration characteristics of the workpiece. An automatic on-machine system to measure the dynamic stiffness of the workpiece enables a reliable and frequent measurement. In this study, an on-machine measurement device for workpiece dynamic stiffness is evaluated. The cause of the difference in natural frequency between the on-machine measurement method and impact test is investigated. The influence of the additional mass by a shaker and accelerometer on the natural frequency is investigated using the Rayleigh-Ritz method. A cutting test is conducted to verify whether appropriate cutting conditions can be set from the measurement results of the on-machine dynamic stiffness measurement. The natural frequency difference between the on-machine measurement method and impact test was caused by the additional mass by the contact of the piezoelectric actuator. When the additional mass is 5% or less of the workpiece equivalent mass, the difference in natural frequency was as small as 10 Hz or less. In the cutting test using the workpiece with the sufficiently large mass, the compliance between the on-machine measurement method and impact test was comparable. When the forced vibration was small, the stability limit was correctly estimated from the on-machine dynamic stiffness measurement.