A novel cryogenic machining concept based on a lubricated liquid carbon dioxide

A novel single-channel supply of pre-mixed (a) liquid carbon dioxide (LCO2) and (b) oil - delivered via minimum quantity lubrication (MQL) - represents a significant advancement in cryogenic-machining technology. In this proof-of-concept study, an attempt is made to advance the understanding of the oil solubility in LCO2 and to analyze the oil-droplets and their impact on machining performance. The results indicate that the physical and chemical properties of oil distinctively affect its solubility in LCO2. The achieved solubility further influences the achievable oil-droplet size and distribution and tool life.