振动切削深孔加工初始偏差对孔直线度误差的影响

构建了振动切削深孔加工钻杆在轴向振动、振动切削力和切削液流体力影响下的多跨动力学有限元模型。引入自由模态综合技术,将钻杆线性自由度的特征模态进行缩减,仅保留具有非线性动力特征的模态,从而可有效降低耦合系统自由度数,减小计算量。利用该缩减后的模型,研究了辅助支撑位置和加工深度与孔直线度误差的作用关系,获得了孔直线度随初始偏差量变化的规律,为大跨度振动切削深孔加工机床的精度设计和加工误差分析提供了依据。通过试验与数值计算结果的对比,验证了所提出方法的有效性与准确性。

Influence of Initial Deviation in Vibrating Deep Hole Drilling on Hole Straightness Error

Based on the extended Hamilton principle,the boring trepanning association(BTA) drilling shaft is established in the form of the Timoshenko element model using finite element method for vibrating drilling process.This model is developed that considers the axial vibration of drilling shaft containing vibrating cutting force and the hydrodynamic forces of cutting fluid.The linear degrees of freedom will be truncated by using modal synthesis with free-interface but nonlinear degrees of freedom of the system are retained in the physical space,and thus,the DOF of the coupled system are reduced.Further,the updated model is acquired to study the relationship between the axial hole straightness deviation and cutting parameters such as drilling shaft length and drilling depth.Simultaneously,the change rules of the axial hole straightness are obtained for the different position of intermediate supports or different initial deviation,so these can make a good reference for the dynamic design of large-scale drilling machine.Through the combination of theories with experiment,the correctness and effectiveness of the above methods have been verified.