车削大螺距螺纹振动特性识别方法

The Identification Method of Vibration Characteristics in Turning Large Pitch Thread

车削大螺距螺纹过程中,机床、刀具和工件振动引起刀-工切削接触关系不断变化,使切削过程处于不稳定状态,已有的振动检测方法,无法揭示出大螺距螺纹车削振动的构成和影响程度.利用工件双自由度和刀具三自由度动力学模型,研究车削大螺距螺纹振动特性,提出振动响应测试和识别方法,建立振动激励判据,提取六种振动时域和频域特征参数,揭示机床主轴与刀具振动对转速、径向切深、加工余量的响应特性.结果表明,来自于机床主轴空转振动激励和刀具上的切削力高频振动激励决定了车削大螺距螺纹切削振动行为.

In the process of turning large pitch thread, the contact relationship between tool and workpiece are constantly changing due to vibration caused by machine, cutting tool and workpiece, so that the cutting process is unstable. The existing vibration test methods can not reveal the composition and the influence degree of turning vi- bration when turning large pitch thread. The vibration characteristics of turning large pitch thread is researched by using the dynamic model of workpiece tow freedom and the cutting tool three degrees of freedom, vibration response testing and identification methods are put forward, incentive criterion of vibration is established, and six kinds of vibration time domain and frequency domain feature parameters are extract. The response characteristics of the machine tool spindle to the tool rotating speed, the radial cutting depth and the machining allowance are revealed. Resuits showed that the excitation caused by machine tool spindle idling vibration and cutting force high frequency vibration of tool determine the turning large pitch thread cutting vibration behavior.