Feasibility of Supercritical Carbon Dioxide Based Metalworking Fluids in Micromilling

Abstract

This article investigates the feasibility of using supercritical carbon dioxide based metalworking fluids (SCCO2 metalworking fluids (MWFs)) to improve micromachinability of metals. Specifically, sets of channels were fabricated using micromilling on 304 stainless steel and 101 copper under varying machining conditions with and without SCCO2 MWF. Burr formation, average specific cutting energy, surface roughness, and tool wear were analyzed and compared. Compared to dry machining, use of scCOi MWF reduced burr formation in both materials, reduced surface roughness by up to 69% in 304 stainless steel and up to 33% in 101 copper, tool wear by up to 20% in 101 copper, and specific cutting energy by up to 87% in 304 stainless steel and up to 40% in 101 copper. The results demonstrate an improvement in micromachinability of the materials under consideration and motivate future investigations of SCCO2 MWF-assisted micromachining to reveai underlying mechanisms of functionality, as well as to directly compare the performance ofscCO2 MWF with alternative MWFs appropriate for micromachining.

Application of cutting fluids in micro-milling — A review

“…The authors stated that [BMIM] [I] had great surface tension (free surface energy), which cleaned out chips and resulted in a smaller surface roughness value [48]. Supekar et al [49] utilized a supercritical carbon dioxide-based cutting fluid (scCO 2 ) to enhance the micro-machinability of AISI 304 and OFHC 101 grade copper (Cu-101), and the results were compared to dry condition. Micro-milling with scCO 2 diminished surface roughness by up to 69% and 33% for AISI 304 and Cu-101, respectively, compared to dry cutting.…”

“…Micro-milling with scCO 2 diminished surface roughness by up to 69% and 33% for AISI 304 and Cu-101, respectively, compared to dry cutting. The reduction in surface roughness with the application of scCO 2 may be due to a local increment in material hardness, which reduces ploughing [49]. The effects of single-tool/multi-tool and supply/non-supply of cold wind machining operations on surface roughness were investigated during micro-milling of STD 11.…”

“…The superior performance of MQL with ultrasonic atomization, in comparison to MQL alone, is due to high-frequency vibrations that allow nanofluid to be broken into smaller and more evenly dispersed droplets that effectively move into difficult-to-reach regions at micro-milling interface. Supekar et al [49] used scCO 2 to enhance the micro-machinability of AISI 304 and Cu-101, and the results obtained from micro-milling with scCO 2 were compared to dry machining. Burr formation was used as a metric of machinability.…”

“…Reduced tool wear in greater loading (1% vol) water-based CuO nanofluids was achieved because of great heat dissipation from the cutting region at a great loading of CuO nanofluid. Supekar et al [49] employed supercritical carbon dioxide (scCO 2 ) to enhance the micro-machinability of AISI 304 and Cu-101, and the results obtained from micro-milling with scCO 2 were compared to dry machining. When scCO 2 was applied during micro-milling, a reduction in wear was found due to enhanced lubrication, heat removal, increased machinability, and hardness, or combination of them [49].…”

Cutting performance of a tool with continuous lubrication of atomized cutting fluid at the tool-chip interface

“…The scCO2 has a good dispersal ability just like gas and has a good solubility just like a liquid. Therefore, the scCO2 can effectively enter the cutting area and play the role of cooling in the worn area [20][21][22]. Rahim etc.…”