高速加工热缩加长刀杆与刀具配合径向夹持刚度分析

STIFFNESS ANALYSIS OF THE MATCHING OF LENGTHENED SHRINK-FIT HOLDER AND CUTTING TOOL IN HIGH SPEED MILLING

建立热缩加长刀杆与刀具配合的有限元模型,给出一种合理确定模型中接触刚度系数的有效方法。随后对不同过盈量、夹持长度及主轴转速对热缩加长刀杆与刀具配合的径向夹持刚度的影响进行分析。最后在建立径向夹持刚度测量方法的基础上,对有限元分析结果进行验证。结果表明,合理的接触刚度系数是正确建立热缩加长刀杆与刀具配合有限元模型的关键;热缩加长刀杆与刀具配合间存在有合理的配合过盈量与夹持长度,以保证配合间夹持均衡而具有很好的夹持刚度,又不至使刀杆强度超过其屈服条件而降低刀杆的使用寿命和精度;当转速超过一定范围时,应考虑离心力对热缩加长刀杆与刀具配合径向夹持刚度的削弱作用。

A finite element model of the matching of lengthened shrink-fit holder and cutting tool is established and an available approach to determine the reasonable contact rigidity coefficient is obtained. Subsequently, the influence of different interference, grip length and spindle speed on the grip rigidity of the matching of lengthened shrink-fit holder and cutting tool. Finally, the finite element model is verified based on the construction of measurement method of the grip rigidity. The results show that a reasonable contact rigidity coefficient is a key to create a correct finite element model of the matching of lengthened shrink-fit holder and cutting tool; there is a reasonable interference and grip length between the lengthened shrink-fit holder and cutting tool so that to have a steepless grip and have a good radial grip rigidity and at the same time to avoid the strength of lengthened shrink-fit holder to exceed it＇ s yield limit which will reduce the precision and service life of lengthened shrink-fit holder; when spindle speed reach a extension the weakening influence of the centrifugal force on the radial grip rigidity of the matching of lengthened shrink-fit holder and cutting tool should been taken into account.