초음파진동을 이용한 다층 PCB 기판의 마이크로 드릴링

Micro drilling of multi-layer PCB with the use of ultrasonic vibration

Multi-layer printed circuit board(PCB) is being used widely for the product with relatively complex circuits such as TV, VTR and FAX. With the rapid enlargement of electronic and IT industry, the hole machining technology on multi-layer PCB is increasingly required to improve. Thus, the micro drilling with ultrasonic vibration can be a good method for hole machining. Unlike conventional drilling, ultrasonic vibration applied drilling introduces less wear and fracture of not only tool but also internal surface of workpiece due to little cutting resistance, thus, machinability can be improved. The experiment is conducted through the comparison between the results of conventional drilling and ultrasonic micro drilling as well as among each results by the variation according to not only feed rate of drill but also amplitude and frequency of ultrasonic vibration. The multi-layer PCB consists of 6 layers and ${\Phi}$0.3 diameter drill was used. As a result, it was found that the state of internal surfaces of holes on multiple layer PCBs is improved by the application of ultrasonic vibration.