Machining Performance of Cryogenic Minimum Quantity Lubrication-Assisted High-Speed Milling 2343ESR Mold Steel

To improve the machinability of 2343ESR mold steel and promote environmentally sustainable machining, this study systematically investigates its cutting performance in high-speed milling assisted by cryogenic minimum quantity lubrication (CMQL). A series of comparative high-speed milling experiments were conducted under dry cutting and CMQL conditions to elucidate the synergistic cooling and friction-reducing mechanisms of CMQL in the cutting zone. The effects of cutting parameters on key indicators including cutting forces, surface roughness, and tool life were investigated. Tool wear mechanisms were further analyzed and compared based on microscopic observations of workpiece surface damage and tool wear morphologies. The results show that, compared with dry cutting, CMQL reduces resultant cutting force by approximately 15.7-25.2% and surface roughness by about 14.6-29.9%. With the assistance of CMQL, the machined surface defects such as tearing, spalling and microcracks were effectively suppressed. In addition, adhesive wear and flank wear of the tool were significantly retarded, thereby achieving a significant improvement in tool life. These findings demonstrate that CMQL-assisted high-speed milling is a high-efficiency, high-quality and environmentally friendly machining technology with broad application potential for 2343ESR mold steel.