Drilling of CFRP with an Electrodeposited Diamond Core Drill – Effects of Air Assistance and Tool Shape –
Yuto Kojima†, Ryutaro Tanaka, Yasuo Yamane, Katsuhiko Sekiya, and Keiji Yamada
Graduate School of Engineering, Hiroshima University
1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
†Corresponding author, E-mail: D155447@hiroshima-u.ac.jp
This research was conducted to investigate the characteristics of electrodeposited diamond core drills when used to cut CFRP.An eccentric core drill was usedto improve cutting characteristics. First of all, the cutting characteristics of a normal core drill were investigated at a few different feed rates and compared with those of a diamond coated twist drill. The effect of air assistance on chip evacuation were also investigated. The cutting forces, surface roughness profile of the hole, and tool appearance were used for evaluation. At the same feed rate, more cutting force was necessary for the normal core drill than for the twist drill. When air was blown in, the cutting forces required by the core drill decreased drastically, but delamination was evident. When air was drawn out, the cutting forces of the normal core drill were almost the same as when there was no air assistance. On the other hand, when an eccentric core drill was used, the cutting force required was lower when air was drawn out than when it was blown in. Additionally, the surface quality of the hole when air was drawn out was greater than when it was blown in. When the eccentric core drill with slits was used while air was drawn out, the cutting forces, surface quality of the hole, and tool appearance were the same as when an eccentric core drill without slits was used. However, there was little core jamming. Therefore, the eccentric core drill with slits had the longest tool life.
-  Y. Yamane, “Special Issue on Difficult-to-Cut Materials, Int. J. of Automation Technology, Vol.7, No.3, pp. 255, 2013.
-  X. Wang, P. Y. Kwon, C. Sturtevant, D. W. Kim, and J. Lantrip, “Tool wear of coated drills in drilling CFRP,” Journal of Manufacturing Processes, Vol.15, No.1, pp. 127-135, 2013.
-  D. F. Liu, Y. J. Tang, and W. L. Cong, “A reveiew of mechanical driling for composite laminates,” Composite Structures, Vol.94, pp. 1265-1279, 2012.
-  W. C. Chen, “Some experimental investigation in the drilling of carbon fiber-reinforced plastic (CFRP) Composite Laminates,” Int. J. Mach. Tools Manufact., Vol.37, No.8, pp. 1097-1108, 1997.
-  U. Heisel and T. Pfeifroth, “Influence of point angle on drill hole quality and machining forces when drilling CFRP,” Procedia CIRP, Vol.1, pp. 471-476, 2012.
-  Y. Karpat, B. Deger, and O. Vahtiyar, “Drilling thick fabric woven CFRP laminates with double point angle drills,” J. of Mat. Proc. Tech., Vol.212, pp. 2117-2127, 2012.
-  S. Tamura and T. Matsumura, “Cutting Force Prediction in Drilling of Unidirectional Carbon Fiber Reinforced Plastics,” Int. J. of Automation Technology, Vol.9, No.1, pp. 59-66, 2015.
-  C. C. Tsao and H. Hocheng, “Parametric study on thrust force of core drill,” Journal of materials processing technology, Vol.192-193, pp. 37-40, 2007.
-  C. C. Tsao and Y. C. Chiu, “Evaluation of drilling parameters on thrust force in drilling carbon fiber reinforced plastic (CFRP) Composite Laminates Using Compound Core-special Drills,” Int. J. Mach. Tools Manufact., Vol.51, pp. 740-744, 2011.
-  K. Y. Park, J. H. Choi, and D. G. Lee, “Delamination-Free and High Efficiency Drilling of Carbon Fiber Reinforced Plastics,” Journal of Composite Materials, Vol.29, No.15, pp. 1988-2002, 1995.