采用薄膜热电偶的多层印刷电路板原位钻削温度测量

In-situ Drilling Temperature Measurement of Multilayer PCB Using Thin Film Thermocouple

针对工业用多层印刷电路板(PCB)加工过程中钻削温度难以准确测量的技术难题,提出了一种基于薄膜热电偶的PCB各板层原位钻削温度测量方法。根据PCB的截面结构采用材料叠层建模方法对PCB钻削过程进行建模仿真,掌握了钻削过程中PCB钻削温度的分布及变化情况,并确定了传感器最佳镀膜位置为钻头进给方向的垂直底部。采用直流脉冲磁控溅射技术,在不同层数的PCB上制备薄膜热电偶传感器,并对其静、动态性能进行研究,结果表明所研制的温度传感器在30~200℃范围内,塞贝克系数为37.4 μV/℃,非线性误差不超过0.65%,动态响应时间为0.095ms。对不同层数的PCB进行了多组钻削温度测量实验,结果显示,钻削过程中4层、12层、20层的最高钻削温度分别为49.30℃、53.90℃、63.90℃,且每组重复实验的温度相对稳定,温度测量误差不超过0.8℃。该测量方法为PCB高速钻削工艺改进提供了参考。

Aiming at the technical problems that it were difficult to measure drilling temperature accurately in the processes of the industrial PCB drilling, a method was proposed based on thin film thermocouple sensor to measure the in-situ drilling temperatures of each layer during PCB drilling processes. The drilling processes of PCB were modeled and simulated by method of layered material modeling according to cross-section structures of PCB. The distribution and variations of PCB drilling temperatures during the drilling processes were clarified. The sensor optimum coating positions were the vertical bottoms of the bit feed directions. Thin film thermocouple sensors were deposited on different PCB layers by DC pulsed magnetron sputtering. The static and dynamic performances of the sensors were studied. Results show that the Seebeck coefficient of the temperature sensor is as 37.4 μV/℃ in the range of 30~200 ℃. The non-linear error is less than 0.65%. The dynamic response time is as 0.095 ms.Several groups of drilling temperature measurements were carried out on different PCB layers. Results show that the maximum drilling temperatures of 4 layers, 12 layers and 20 layers during drilling processes are 49.30 ℃, 53.90 ℃ and 63.90 ℃ respectively. The temperature of each group of repeated experiments is stablize, and the errors are less than 0.8 ℃. In summary, the method provides a reference for improving PCB high speed drilling processes.