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|| Stampfer, B.; Zanger, F. & Schulze, V. (2018), "In-Process Analysis of Minimum Quantity Lubrication during Drilling of AISI 4140". Advances in Production Research, eds. Schmitt, R. & Schuh, G., pp. 541-550.
Minimum quantity lubrication (MQL) is an established concept to meet high ecological and economical demands in metal machining. Compared to flood cooling, MQL massively reduces the efforts associated with the supply and disposal of the lubricants and the handling of emulsion contaminated chips. At the same time, MQL can reach a similar tool life. The mechanisms that have an influence on this effect are a matter of ongoing research.
For this work, aerosol was generated by a 1-channel MQL system and supplied to a drilling process with AISI 4140 specimen. The drilling torque, feed force and workpiece temperatures are evaluated under different MQL air input pressures and tool cooling channel lengths. The results are interpreted by the help of flood cooling reference tests and high speed camera recordings, which reveal the open-jet atomisation of lubrication ligaments at the tool exit, arising from different MQL operation parameters.
| [ 2 ]
|| Stampfer, B.; Golda, P.; Zanger, F.; Schießl, R.; Maas, U. & Schulze, V. (2019), "Thermomechanically coupled numerical simulation of cryogenic orthogonal cutting". 17th CIRP Conference on Modelling of Machining Operations (17th CIRP CMMO), eds. Ozturk, E.; Mcleay, T. & Msaoubi, R., pp. 438-443.
During machining of Ti-6Al-4V, high thermal loads arise, which demand for advanced cooling concepts, such as the application of liquid nitrogen. An efficient approach to analyze the thermomechanical mechanisms which influence the tool life and the workpiece distortions is the usage of coupled numerical simulations.
In this work, the Finite -Element-Method was used to simulate the tool-workpiece-interaction and the chip formation, whereas the detailed treatment of the nitrogen fluid flow and its heat transfer is solved by an in-house program using the Finite-Difference-Method. Both simulations are coupled by appropriate boundary conditions, which are updated iteratively during the calculation.