基于动力学的机床加工运动分析

Analysis of Machine Tool's Movement Based on Dynamics

数控定梁龙门机床的加工精度受多种因素影响,包括零部件的制造、装配误差、材料的刚度阻尼、振动、材料切削厚度等。从提高机床加工精度出发,根据拉格朗日动力学原理建立了机床的动力学模型;分析横梁、床身等部件的自由度关系,建立了机床运动学模型;采用ADAMS软件仿真机床的瞬态动力和运动关系,对比研究了不同的瞬态切削力变化对机床切削位移、速度的影响。结果表明:当机床切削厚度增大时,切削力、切削速度和切削加速度会随之增大,同时切削速度和加速度的变化滞后切削厚度和切削力的变化;在切削受力突变处切削速度有波动,移动加速度有突变,波动时间滞后切削力突变时间。仿真结果与实际机床加工情况吻合,为机床加工的运动分析提供参考。

The machining accuracy of NC fixed beam gantry machine tool is influenced by many factors, including parts manufac- turing, assembly, material stiffness damping, vibration and cutting thickness. Inorder to raise machine tool＇s machining precision, ma- chine tool＇ s dynamic modal was set up based on Lagrangian dynamic principle. By analyzing the freedom of beam and lathe bed, kine- matic modal was set up. By using ADAMS software, the relationship of machine tool＇ s cutting force and movement was simulated, and the influence of different instantaneous cutting force changeon displacement and speed was contrasted. The results show that ： when ma- chine tool＇ s cutting thickness increases, the cutting force, cutting speedand cutting acceleration increase, the changes of the cutting speed and acceleration lag the changes of cutting thickness and cutting force. The simulation results accord with the actual machine tool processing, and it providereference formovement analysis.