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控技术，借由侦测微小的声音与振动讯号的功率位准，厘清振动频率产生的原因，并指定监控的频率.设计了圆锥喇叭型和圆柱型夹具作为研磨配重，以精确检测低频和高频振荡信号。前者主要是为了放大振动，后者主要是为了避免共振。加速度传感器或压电传感器安装在工作的顶部，以检测高达100 kHz的频率的信号。当模型盘与工件垂直振动时，夹具的振动特性为典型的二阶系统，其固有频率为1.5 ~ 2kHz。我们测量了磨粒的直径分布，并估计了可能与接触有关的磨粒数量。基于赫兹定理，将接触部分的弹性变形视为弹簧，得到了接触部分固有频率的表达式。在研磨盘缓慢旋转的情况下，由于接触状态的变化，使得工作振动的频率在0.5 ~ 4kHz之间，这一情况似乎发生了完全的变化.在各种工艺条件下产生的振荡的频率分布表明，与加工状态相关的峰值频率存在于0.5 kHz至2 kHz的范围内，并且以dB为单位的峰值与工件的表面粗糙度具有线性关系。

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.