Machining center cutting oil, as a key supporting material in metal cutting processes, has its core functions systematically summarized into eight major roles: lubrication and friction reduction, cooling and temperature reduction, chip removal and cleaning, rust and corrosion prevention, tool life extension, improvement of machining accuracy, reduction of workpiece thermal deformation, and environmental safety. These functions work together to ensure the stability and efficiency of the cutting process. Lubrication and friction reduction lower the friction coefficient between the tool and workpiece by forming an oil film, while cooling and temperature reduction rapidly dissipate heat from the cutting zone. Together, these constitute the foundational functions of cutting oil. The chip removal and cleaning mechanism effectively clears away metal chips generated during machining, and the rust and corrosion prevention characteristics protect both the machine tool and workpiece from corrosion, which is particularly crucial in humid environments. From a process optimization perspective, cutting oil significantly extends tool life, enhances surface finish, and suppresses deformation caused by high temperatures. Additionally, modern cutting oils are designed with environmentally friendly formulations to minimize their impact on operator health and the environment. These eight functions are interrelated, forming a comprehensive cutting protection system.

1. Lubrication and Friction Reduction
   Cutting oil forms a lubricating film at the contact surface between the tool and workpiece, effectively reducing direct metal friction and lowering cutting resistance by approximately 30%-50%. Its extreme pressure additives maintain oil film strength under high-pressure conditions, making it particularly suitable for difficult-to-machine materials such as stainless steel and titanium alloys.

2. Cooling and Temperature Reduction
   Through forced convection and vaporization heat absorption mechanisms, it rapidly dissipates heat from the cutting zone, reducing tool temperature by 150-300°C. Although mineral oil-based products have lower thermal conductivity compared to water-based fluids, stable temperature control can still be achieved through circulation systems.

3. Chip Removal and Cleaning
   Low-viscosity formulations, combined with light components such as kerosene, flush away chips and prevent built-up edge formation. In deep-hole drilling, they maintain clear chip evacuation channels, avoiding scratches on machined surfaces.

4. Rust and Corrosion Prevention
   Containing organic amine rust inhibitors, it forms a passivation film on metal surfaces, providing over 72 hours of inter-process protection for cast iron components. It is especially suitable for rainy regions or intermittent operating conditions in automated production lines.

5. Tool Life Extension
   It reduces flank wear, increasing the durability of carbide tools by 2-3 times. In high-speed milling, it delays the propagation of thermal cracks in tools.

6. Improvement of Machining Accuracy
   It suppresses built-up edge formation, reducing surface roughness Ra values by 0.8-1.6 μm. In precision thread machining, it ensures pitch errors remain below 0.02 mm.

7. Reduction of Workpiece Thermal Deformation
   It controls cutting temperature fluctuations within ±5°C, reducing deformation in thin-walled parts by over 40%. The effect is particularly significant for low-melting-point materials such as aluminum alloys.

8. Environmental Safety
   Chlorine-free formulations avoid the generation of harmful gases, with biodegradability rates >90%. Some products are NSF H1 certified, allowing incidental contact with food-grade workpieces.