Influence of chisel edge thinning on helical point micro-drilling performance
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Chisel edge thinning can effectively improve the drilling performance of austenitic stainless steel. Four kinds of helical point micro-drills, each with a thinned chisel edge of a distinct length, are fabricated based on the mathematics models of the micro-drill by using a six-axis computer numerical control tool grinder. Micro-drilling experiments on 304 stainless steel are conducted. Drilling performance is evaluated according to the measured and observed micro-hole machining quality, chip morphology, thrust force, and tool wear of the micro-drill tip. With a decrease in the chisel edge length, the micro-holes drilled using thinned micro-drills have small entrance burrs, roundness errors, and regular shapes, which are attributed to an increase in self-centering capability. Owing to increased equivalent chip thickness and different directions of chip flow, micro-drills with thinned chisel edge can generate more small-size chips and improve chip breaking. In addition, the inner cutting edge with a positive rake angle replaces the chisel edge with a negative rake angle to cut the workpiece, significantly reducing the chip curl, thrust force, and tool wear of micro-drills. However, helical point micro-drills with critical chisel edge lengths by thinning exhibit less thrust force and tool wear than do helical point micro-drills with no chisel edge because of the increase in the uncut chip width of the micro-drill. Thus, with the selected parameter range, the optimal helical point micro-drill is the micro-drill with a specific chisel edge length by thinning to improve drilling performance.
KeywordsChisel edge thinning Stainless steel Micro-drill Drilling performance
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This work was supported by the National Natural Science Foundation of China (No. 51575049), National Basic Research Program of China (No. 2015CB059900), and Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology (No. 2015KM005).
- 1.Zhang SY, Liang ZQ, Wang XB, Zhou TF, Jiao L, Yan P, Jian HC (2016) Grinding process of helical micro-drill using a six-axis CNC grinding machine and its fundamental drilling performance. Int J Adv Manuf Technol 86(9–12):1–13Google Scholar
- 11.Nanbu Y, Ochiai K, Ehara K, Matsuda S (2010) High-aspect-ratio microdrilling of the nozzle for gas turbine(2nd Report): effect of thinning of microdrill and ultrasonic vibration. Proceedings of JSPE Semestrial Meeting (Vol.2010, pp. 1017–1018). The Japan Society for Precis Eng.Google Scholar
- 15.Kang SK, Lin C, Ehmann KF (1993) Comparative analysis of planar and helical micro-drill points. Trans NAMRI/SME XXI:189–196Google Scholar
- 18.Zhang SY, Wang XB, Liang ZQ, Zhou TF, Jiao L, Yan P (2017) Modeling and optimization of the flute profile of micro-drill. Int J Adv Manuf Technol 1–14.Google Scholar