International Journal of Machine Tools & Manufacture 41 (2001) 2245–2260 Shane Y. Hong, Irel Markus, Woo- cheol Jeong. New cooling approach and tool life improvement in cryogenic machining of titanium alloy Ti-6Al-4V. Steven McFarland October 16, 2009. Introduction.
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International Journal of Machine Tools & Manufacture 41 (2001) 2245–2260
Shane Y. Hong, Irel Markus, Woo-cheolJeong
New cooling approach and tool life improvement incryogenic machining of titanium alloy Ti-6Al-4V
October 16, 2009
Fig. 2. The hardness of Ti-6Al-4V versus temperature.
Fig. 1. The strength and elongation of Ti-6Al-4V versus temperature.
Fig. 5. A photograph showing LN2 flowing out of the nozzle.
Fig. 4. The design implementation of the cryogenic nozzle. (a) When both primary nozzle and auxiliary nozzle are used to inject liquid nitrogen; (b) only the primary nozzle is used.
Fig. 6. Tool life comparison between flooding LN2 and emulsion cooling.
Fig. 7. Tool life comparison of different cooling approaches at 1.5 m/s (300 ft/min).
Table 1. Highest temperatures at the cutting tool insert measured by the imbedded thermal couple at the tool insert and obtained by finite element (FE) analysis and their corresponding tool lives
Clearly, focused cooling with a small LN2 flowrate to the rake, or to both the rake and flank, are the preferred approaches for cryogenic machining.
Table 3. Tool life testing result for machining Ti-6Al-4V
For the cryogenic cooling, especially with “two nozzles on”, an adequate tool life can be obtained even at a cutting speed of 2.5 m/min, at which even the emulsion cooling can only lead to an unacceptable tool life (less than 1 min).
Fig. 10. Expanded tool life testing results in terms of total volume removal at different cutting speeds.