Lubrication regimes

Lubrication regimes describe different ways lubricants protect moving parts. In **boundary lubrication**, a thin film forms, preventing direct metal contact but offering less protection. **Hydrodynamic lubrication** occurs when a thick, continuous film completely separates surfaces, allowing smooth movement. **Elastohydrodynamic lubrication** happens under high pressure, where the lubricant and surfaces deform slightly, still maintaining separation. These regimes affect wear and efficiency: boundary provides minimal protection, hydrodynamic offers optimal isolation, and elastohydrodynamic occurs during heavy load conditions. Understanding these helps in choosing the right lubricant and design for machinery longevity and performance.