High speed cryogenic finish machining of Ti - 6Al4V with polycrystalline diamond tools

Schoop, Julius; Sales, Wisley Falco; Jawahir, I.S.

doi:10.1016/j.jmatprotec.2017.07.002

Cited by 74 publications

(12 citation statements)

References 16 publications

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“…This can be attributed to the capacity of cryogenic machining to provide better cooling and lubrication through the reduction of heat generation at the cutting zone. Schoop et al [17] used polycrystalline diamond tools to machine Ti-6Al4-V alloy under three different cooling/lubricating environments: cryogenic cooling, hybrid cooling/lubrication (cryogenic cooling and minimum quantity lubrication), and conventional flood cooling. In this study, it was observed that the use of hybrid cooling/lubrication approach resulted in better surface integrity, lower cutting force.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on chip deformation of Ti-6Al-4V titanium alloy in cryogenic cutting

Zhao

Gong

Ren

et al. 2018

Int J Adv Manuf Technol

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This paper first develops a cryogenic cutting system with adjustable jet temperature (− 196~20°C), and then carries out a series of dry cutting and cryogenic turning experiments for titanium alloy. Metallographic microscope is used to observe the chip morphology of titanium alloy and the geometric characteristic parameters of the chip are measured using a Digimizer image measurement software. The influence of cutting speed and cooling conditions on the chip morphology, chip height ratio, and serrated pitch has been analyzed. The experimental results reveal that the cutting speed and cooling conditions play significant roles on the chip morphology and serrated characteristics of titanium alloy. During the cryogenic cutting process, with the increase of cutting speed, the chip height ratio and serrated pitch of titanium alloy chip increase. It has been found that under the condition of cryogenic cutting, the lower jet temperature, the more obvious serrated characteristic of titanium alloy chip. It is also found that the fibrous adiabatic shear band exists in the shear zone; the chip height ratio and serrated pitch remarkably increase.

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Section: Introductionmentioning

confidence: 99%

Experimental study on chip deformation of Ti-6Al-4V titanium alloy in cryogenic cutting

Zhao

Gong

Ren

et al. 2018

Int J Adv Manuf Technol

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“…Better heat dissipation mechanism helps keeping a check on tool wear progress, which, in turn, helps maintaining cutting edge's geometry and suppressing the machining forces. In other works, hybrid cryogenic cooling/lubrication was reported to yield the lowest machining forces compared to both emulsion and cryogenic conditions in machining of titanium alloys [11,13]. The effect of milling orientation was neither very significant nor clear.…”

Section: Specific Cutting Energy and Machining Forcesmentioning

confidence: 82%

“…Sartori et al reported that an MQL system amalgamated with a CO 2 and LN 2 distribution system could optimize the lubrication and cooling effect, leading to a significant reduction in crater wear [10]. In another study, it was reported that machining under flood coolant does not reduce surface roughness [11]. The authors also reported that LN 2 hybridized with oil-based MQL can yield the lowest cutting forces of all the tested coolants.…”

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confidence: 99%

Sustainable Milling of Ti-6Al-4V: Investigating the Effects of Milling Orientation, Cutter′s Helix Angle, and Type of Cryogenic Coolant

Iqbal

Suhaimi

Zhao

et al. 2020

Metals

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Ti-6Al-4V, the most commonly used alloy of titanium, possesses excellent mechanical properties and corrosion resistance, which is the prime reason for the continual rise in its industrial demand worldwide. The extraordinary mechanical properties of the alloy are viewed as a hindrance when it comes to its shaping processes, and the process of milling is no exception to it. The generation of intense heat flux around the cutting zones is an established reason of poor machinability of the alloy and unacceptably low sustainability of its machining. The work presented in this paper attempts to enhance sustainability of milling Ti-6Al-4V by investigating the effects of milling orientation, cutter's helix angle, cutting speed, and the type of cryogenic coolant and lubricant on the sustainability measures, such as tool damage, cutting energy consumption, process cost, milling forces, and work surface roughness. It was found that micro-lubrication is more effective than the two commonly used cryogenic coolants (carbon dioxide snow and liquid nitrogen) in reducing tool wear, work surface roughness, process cost, and energy consumption. Furthermore, down-milling enormously outperformed up-milling with respect to tool wear, work surface quality, and process cost. Likewise, the high levels of cutter's helix angle and cutting speed also proved to be beneficial for milling sustainability.Metals 2020, 10, 258 2 of 25 environmentally [3]. The problem is generally negotiated either by lowering the material removal rates or by applying emulsion-based coolants, neither of which actually offers a sustainable solution.With regard to quashing the intense heat flux around the cutting areas, the application of cryogenic fluids, especially liquid nitrogen (LN 2 ), fares very well. The fluids offer a viable solution because of extremely low operational temperatures, no waste generation, and controllable flow rates. Additionally, application of micro-lubrication, also known as minimum quantity of lubrication (MQL), also proved to be very beneficial in enhancing tool life and improving surface quality in machining of titanium alloys conducted at medium cutting speeds [4,5]. MQL is a near-dry machining method in which a miniscule quantity of lubricating oil is pulverized into a stream of air, and the resulting aerosol is applied onto the cutting areas [6].Although steady progress is being made regarding quantification of the effects of cryogenic coolants with regard to the continuous machining processes, not much effort is being put up concerning interrupted machining processes, such as milling. Cryogenic milling is distinct from continuous machining processes performed under cryogenic environment in the sense that the cutting teeth of a milling tool periodically and rapidly engage and disengage with the work material, leading to cyclic heating (caused by thermal energy released by work material's plastic deformation) and cooling (caused by interaction with the incoming cryogenic fluid) of the cutting edges. Such a course is expected to induce...

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“…However, the increased cutting forces that go along with this increased mechanical strengthening of the cryogenically machined surface may not be acceptable in some applications, such as thin-walled turbine blades and long and slender shafts. Therefore, future work will need to investigate the trade-off and optimization of the positive effects of cooling with those of lubrication, as has been preliminarily done in some of the author's previous work for 'hybrid' high speed cryogenic machining of Ti-6Al4V with polycrystalline diamond tools (PCD) [26]. In that particularly study, reduced cutting forces and increased tool-life were noted for the combined cryogenic and oil lubrication mode, which was compared to cryogenic-only and oil lubricated machining.…”

Section: Comparison and Interpretation Of Experimental Data And Modelmentioning

confidence: 99%

In-Situ Calibrated Modeling of Residual Stresses Induced in Machining under Various Cooling and Lubricating Environments

Schoop

2021

Lubricants

Self Cite

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Although many functional characteristics, such as fatigue life and damage resistance depend on residual stresses, there are currently no industrially viable ‘Digital Process Twin’ models (DPTs) capable of efficiently and quickly predicting machining-induced stresses. By leveraging advances in ultra-high-speed in-situ experimental characterization of machining and finishing processes under plane strain (orthogonal/2D) conditions, we have developed a set of physics-based semi-analytical models to predict residual stress evolution in light of the extreme gradients of stress, strain and temperature, which are unique to these thermo-mechanical processes. Initial validation trials of this novel paradigm were carried out in Ti-6Al4V and AISI 4340 alloy steel. A variety dry, cryogenically cooled and oil lubricated conditions were evaluated to determine the model’s ability to capture the tribological changes induced due to lubrication and cooling. The preliminarily calibrated and validated model exhibited an average correlation of better than 20% between the predicted stresses and experimental data, with calculation times of less than a second. Based on such fast-acting DPTs, the authors envision future capabilities in pro-active surface engineering of advanced structural components (e.g., turbine blades).

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High speed cryogenic finish machining of Ti - 6Al4V with polycrystalline diamond tools

Cited by 74 publications

References 16 publications

Experimental study on chip deformation of Ti-6Al-4V titanium alloy in cryogenic cutting

Experimental study on chip deformation of Ti-6Al-4V titanium alloy in cryogenic cutting

Sustainable Milling of Ti-6Al-4V: Investigating the Effects of Milling Orientation, Cutter′s Helix Angle, and Type of Cryogenic Coolant

In-Situ Calibrated Modeling of Residual Stresses Induced in Machining under Various Cooling and Lubricating Environments

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