Development of Vibration Diagnostic System for Improving Thread Machining Technology

提出了一种新的振动分析方法，该方法特别关注了工件旋转运动与刀具直线进给运动之间的同步误差，这种误差直接导致了加工螺纹的超前误差。在螺纹机和螺纹磨床上对该方法进行了验证。研究结果总结如下：1。一种新的螺纹切削振动分析方法由扭静态特性试验、扭动态特性试验、间歇切削试验、怠速运行试验和螺纹切削试验组成。通过脉冲切削扭转动态特性试验，可以得到刀具与工件之间的扭转固有频率。扭振固有频率可通过断续切削试验确定。利用快速傅立叶变换分析仪对空转和螺纹切削过程中记录的同步误差进行处理。通过参考被测螺纹机中包含的旋转传动机构的原理图，根据FFT分析仪处理的同步误差的频率成分，可以揭示导致加工螺纹超前误差的特定部件。一种新的螺纹磨削振动分析方法，包括空转试验、快速停机试验和螺纹磨削试验。采用与螺纹加工机相同的方法处理空转和螺纹磨削时的同步误差后，可以发现引起磨削螺纹引线误差的特定部位。以某螺纹磨床为例，确定了驱动横移工作台的丝杠在一节距内产生的主要导偏误差，并通过导偏误差测量试验得到了明显的识别。新提出的螺纹切削和螺纹磨削振动分析方法可有效地应用于许多机械加工车间中使用的其他螺纹生产设备的振动诊断。

A vibration analysis method was newly proposed which was paied special attention to the synchronous error between rotational motion of a workpiece and straight feed motion of a cutting tool, which directly caused lead error of a machined thread. The method was demonstrated on a threading machine and a thread grinding machine. The results are summarized as follows :1. A new vibration analysis method for thread cutting consists of torsional static characteristic test, torsional dynamic characteristic test, intermittent cutting test, idle running test and thread cutting test.2. By applying torsional dynamic characteristic test by impulsive cutting, torsional natural frequency between a cutting tool and a workpiece can be obtained. The torsional natural frequency can be identified by intermittent cutting test.3. Synchronous error which was recorded during idle running and thread cutting was processed by an FFT ( fast Fourier transform ) analyzer. By consulting a schematic drawing of a rotational transmission mechanism which is contained in a tested threading machine, specific parts can be revealed which cause a lead error of a machined thread based on frequency components of synchronous error processed by an FFT analyzer.4. A new vibration analysis method for thread grinding consists of idle running test, rapidly stopping test and thread grinding test.5. After synchronous error during idle running and thread grinding was processed by the same manner as the case of threading machine, specific parts can be revealed which cause a lead error of a ground thread. In the case of a tested thread grinding machine, it was ascertained that a lead screw for driving a traverse table mainly caused a lead error during one pitch which was remarkably recognized by lead error measuring test.6. A newly proposed vibration analysis method for thread cutting and thread grinding can be effectively applied to diagnose other thread production equipments which are used in many machine shops.