RELATION BETWEEN DRILL BIT TEMPERATURE AND CHIP FORMS IN DRILLING OF CARBON BLACK REINFORCED POLYAMIDE

Abstract

Polyamides have many application fields due to their good mechanical strength, high impact strength, good sliding properties etc. Recently, electrically conductive polyamides can be produced by adding carbon black, graphene, metals and carbon nanotubes and their usage have increased. Polyamides are generally manufactured by injection molding and extrusion method but drilling is often needed for the final product. In literature, there are not many studies on the drilling of polyamides and polyamide composites. In this study, drill bit temperature and chip forms were investigated during the drilling of unreinforced polyamide and carbon black reinforced electrically conductive polyamide. Drilling experiments were performed at three different feeds and cutting speeds. Depending on the experimental results, the drill bit temperature increased with increasing the cutting speed and decreasing the feed. Higher drill tip temperatures were measured in the drilling of carbon black reinforced polyamide than that occurred in the drilling of unreinforced polyamide. The chips were more deformed at high cutting speed and low feed. In addition, the chip forms of carbon black reinforced polyamide were observed more regular than that of unreinforced polyamide due to the fact that the chips of carbon black reinforced polyamide could conduct the heat to the drill bit and they were less affected by the heat.

Keywords

• Polyamide, carbon black, drill tip temperature, chip form

References

1. Ahmad, J.Y.S., 2009. Machining of Polymer Composites. Springer: New York.
2. Altan, M., and Altan, E., 2014. Investigation of burr formation and surface roughness in drilling engineering plastics. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 36, pp. 347-354.
3. Endo, H., and Marui, E., 2006. Small-hole drilling in engineering plastics sheet and its accuracy estimation. International Journal of Machine Tools and Manufacture, 46, pp. 575-579.
4. Gaitonde, V.N., Karnik, S.R., Rubio, J.C.C., Abrão, A.M., Correia, A.E., and Davim, J.P., 2012(a). Surface roughness analysis in high-speed drilling of unreinforced and reinforced polyamides. Journal of Composite Materials, 46(21), pp. 2659-2673.
5. Gaitonde, V.N. Karnik, S.R., Rubio, J.C.C., Leite, W.O., and Davim, J.P., 2012(b). Experimental studies on hole quality and machinability characteristics in drilling of unreinforced and reinforced polyamides. Journal of Composite Materials, 48(1), pp. 21-36.
6. Kim, I., 2007. Investigation of electrically conductive acrylonitrile-butadiene rubber. Journal of Vinyl & Additive Technology, 13(2), pp. 71-75.
7. Rubio J.C.C., Panzera, T.H., Abrão, A.M., Faria, P.E., and Davim, J.P., 2011. Effects of high speed in the drilling of glass whisker-reinforced polyamide composites (PA66 GF30): statistical analysis of the roughness parameters. Journal of Composite Materials, 45(13), pp. 1395-1402.
8. Rubio, J.C.C., da Silva, L.J., Leite, W.O., Panzera, T.H., Filho, S.L.M.R., and Davim, J.P., 2013. Investigations on the drilling process of unreinforced and reinforced polyamides using Taguchi method. Composites Part B- Engineering, 55, pp. 338-344.

9. Rubio, J.C.C., Panzera, T.H., and Scarpa, F., 2015. Machining behaviour of three high-performance engineering plastics. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 229(1), pp. 28-37.
10. Saad, A.L.G., Aziz, H.A., and Dimitry, O.I.H., 2004. Studies of electrical and mechanical properties of poly(vinyl chloride) mixed with electrically conductive additives. Journal of Applied Science, 91, pp. 1590-1598.
11. Uysal, A., Altan, M., and Altan, E., 2012. Effects of cutting parameters on tool wear in drilling of polymer composite by Taguchi method. International Journal of Advanced Manufacturing Technology, 58, pp. 915-921.
12. Wang, X., Kwon, P.Y., Sturtevant, C., Kim, D., and Lantrip, J., 2013. Tool wear of coated drills in drilling CFRP. Journal of Manufacturing Processes, 15, pp. 127-135.
13. Zhijun, Q., Xingxiang, Z., Ning, W., and Jianming, F., 2009. Poly(1,3-butylene acid)/carbon black as electrical conductive polymer composites. Polymer Composites, 30(11), pp. 1576-1584.