BASIC RESEARCH ON LAPPING PROCESS WITH INTRODUCING A METHOD OF ACOUSTIC AND BIVRATION MONITORING

在本研究中，我们提出并建立了研磨过程的监测技术，通过检测微小的声学和振动信号的功率级，阐明振动频率产生的原因，并指定监测的频率。设计了锥形喇叭和圆柱形夹具作为研磨重物，实现了低频和高频振荡信号的精确检测。前者主要是为了放大振动，而后者则是为了避免共振。在工作台顶部安装了加速度传感器或压电传感器，以检测频率高达100 kHz2的信号。当有一个工件的模型盘垂直振动而不旋转时，跳汰机的振动特性是典型的二阶系统，其固有频率为1.5-2 kHz。我们测量了磨料颗粒的直径分布，并估计了可能与接触有关的颗粒数量。根据赫兹定理，将接触部分的弹性变形视为弹簧，得到了固有频率的计算公式。在大腿缓慢旋转的情况下，由于接触条件每时每刻都在变化，情况似乎完全改变了，工作振动的频率扩展到了0.5-4 kHz。不同工艺条件下产生振动的频率分布表明，与加工状态有关的峰值频率存在于0.5 kHz~2 kHz范围内，峰值单位为分贝，与加工表面粗糙度呈线性关系。

In this research, we proposed and established the monitoring technique of lapping process by detecting the power level of small acoustic and vibration signals, clarifying why the vibration frequency is generated, and specifying the frequency for monitoring.1. A conical horn type and a cylindrical type jig as lapping weights were designed to detect low level and high frequency oscillating signal precisely. The former was designed mainly to amplify the vibration and the latter was to avoid the resonance. An acceleration pick-up or a piezoelectric sensor was mounted on the top of work to detect the signal up to the frequency of 100 kHz.2. When a model lap with a work was vibrated vertically without rotating, the characteristics of oscillation of the jig was that of typical second order system with the natural frequency of 1.5 -2 kHz. We measured the diameter distribution of abrasive grains and estimated the number of grains that might be concerned with the contact. Based on the Hertz's theorem, the elastic deformations of the contact portion were regarded as springs and the formulation of the natural frequency was obtained. In the case that the lap was rotating slowly, the situation seemed wholly changed and the frequency of the work vibration spread to 0.5 - 4 kHz , because the condition of contact was varied every moment.3. The frequency distributions of generated oscillation under various process conditions shows that the peak frequency that connects to the state of processing exists within the range from 0.5 kHz to 2 kHz and the peak value in dB has a linear relation to the surface roughness of the work.