Mechanical drilling of PCB micro hole and its application in micro ultrasonic powder molding
Abstract
Purpose
This paper aims to present the main factors affecting the mechanical drilling of the printed circuit board (PCB for short) micro-holes and method of micro-ultrasonic powder molding (micro-UPM for short) by utilizing PCB micro-hole array.
Design/methodology/approach
To optimize the drilling process, the paper proposes the on-line monitoring methods for the drilling process including drilling force, drilling temperature, high-speed photography and vibration signals. Taking 0.10 and 0.15 mm micro-drilling as examples, the paper analyzes the drilling process of ultra-small micro-holes. Finally, by taking the PCBs with 0.10 and 0.15 mm micro-hole arrays as the micro-cavity inserts, utilizing ultra-high-molecule weight polyethylene powder with the average particle size of about 150 μm as raw material, two sizes of micro-cylinder array polymer parts are fabricated through micro-UPM process.
Findings
PCB micro-cavity inserts with micro-hole arrays fabricated by mechanical drilling has the advantages of low costs, high efficiency and good consistency. Taking 0.10 and 0.15 mm micro-drilling as examples, it is found that the both measured apertures are about 10.0 μm more than the diameter of the micro-drill bits on average. The average diameter of the micro-cylinders by micro-UPM process is smaller than that of the micro-hole with the same specification, while the value of the roughness of the cylinder surface is more than that of the hole-wall surface with the same specification.
Originality/value
This paper describes the challenges and the developments of mechanical drilling and by using PCB micro-cavity inserts with micro-hole arrays fabricated by mechanical drilling, two different micro-cylinder array polymer parts are successfully made and thus the application area of PCB micro-drilling is broadened.
Keywords
Acknowledgements
This work is supported by the National Natural Science Foundation of China (No.51175348, 51405306 and 51375315), the Project funded by China Postdoctoral Science Foundation (No.2014M552233), the Research and Development Foundation of Science and Technology of Shenzhen (No.JCYJ20140418095735629). The authors are grateful to Shenzhen Jinzhou Precision Technology Corp., for their generous offer of experimental equipment.
Citation
Liang, X., Li, B., Fu, L., Wu, X., Shi, H., Peng, T. and Xu, B. (2015), "Mechanical drilling of PCB micro hole and its application in micro ultrasonic powder molding", Circuit World, Vol. 41 No. 2, pp. 87-94. https://doi.org/10.1108/CW-12-2014-0057
Publisher
:Emerald Group Publishing Limited
Copyright © 2015, Emerald Group Publishing Limited