摘要
在铣削加工过程中,由再生效应引起的颤振严重影响零件表面的加工质量,降低生产效率.合理分析铣削过程中颤振的产生机理和影响因素,获得稳定加工条件下最合适的加工参数,是实现加工过程的高效化和精密化的核心环节和基础.通过等效地简化"零件-刀具"系统为两自由度弹簧阻尼系统,将刀具和零件的接触过程转化为物理模型,建立了多因素耦合的铣削动力学模型.其次,通过全离散法将铣削动力学模型的求解等效地转化为传递函数矩阵特征值的求解,确定了所有特征值的模小于1为加工稳定性的判据.最后,通过准确标定和辨识铣削力参数和模态参数,揭示并实验验证了铣削稳定性的径向浸入比与螺旋角效应、过程阻尼效应和铣刀结构模态的耦合效应,认为在小径向切深下,螺旋角效应较为明显,当径向浸入比逐渐增大,螺旋角效应逐渐减小;在低转速时,过程阻尼效应作用明显,与只考虑再生效应相比,能获得更大的稳定域,随着转速增加,过程阻尼效应作用逐渐减小,考虑过程阻尼所获得的稳定域与只考虑再生效应获得的稳定域趋于重合.
The chatter caused by the regeneration effect will strongly influence a workpiece surface’s machining quality during the milling process and decrease the efficiency of output.Furthermore,under the condition of stable machining,the study of the generative process and effect factors should be performed to achieve the optimum milling parameters.High efficiency and accuracy in the machining process is important.In particular,by simplifying the workpiece-tool milling system as a two-degree spring-damping system,the multiple factors couple dynamics model of the milling mechanism is calculated by transforming the interaction between the workpiece and the milling tool into a physical model.And then the whole process of discretization is implemented to solve the dynamics problem for the transfer function matrix’s values.It is possible to determine the judgment criterion of machining stability by the relationship of the standard of all own values below.Finally,the parameters of the milling force and vibration mode are adjusted precisely to show the effect of the radial immersion ratio and helix angle,the damping effect of the process and the coupling effect of the structural mode.The experimental results show that under the condition of a limited radial immersion ratio,the effect of the helix angle on machining stability is evident.The larger the radial immersion ratio,the lower the machining stability effect of the helix angle.When the spindle speed is small,the process damping will affect the machining stability for the greater stability region compared to the regeneration effect.The effect of process damping is steadily decreased with the increase in spindle speed.The region of stability obtained through process damping would correlate with the region of stability obtained through the effect of regeneration.
作者
秦国华
娄维达
吴竹溪
石泰
吴铁军
QIN GuoHua;LOU WeiDa;WU ZhuXi;SHI Tai;WU TieJun(School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China;Department of Mechanical and Electrical Engineering,Dongguan Polytechnic,Dongguan 523808,China)
出处
《中国科学：技术科学》
EI
CSCD
北大核心
2020年第9期1211-1225,共15页
Scientia Sinica(Technologica)
基金
国家自然科学基金(批准号:51765047)
江西省主要学科学术和技术带头人培养计划(编号:20172BCB22013)
江西省科技厅重大研发计划(编号:20192BBEL50001)资助项目。
关键词
颤振
稳定性叶瓣图
过程阻尼
模态耦合效应
螺旋角
径向浸入比
chatter
stability lobe diagram
process damping
mode coupling effect
helix angle
radial immersion ratio
