Dynamic contact angle model of bionic micro-abrasive droplet wetting and experimental study

Abstract

Micro-grinding techniques are widely used in orthopedic surgeries involving bone tissue removal. However, insufficient dynamic wetting of coolant droplets on rotating micro-grinding tools can disrupt coolant coverage and interfacial heat transfer, causing thermal damage during bone micro-grinding. Bionic hydrophilic/hydrophobic tools inspired by desert beetles offer a promising approach, but the relationship between droplet wetting dynamics and grinding temperature remains unclear. This study investigated droplet dynamics and interfacial forces on bionic micro-grinding tools to clarify their wetting behavior and its relationship with grinding temperature. The combined effects of centrifugal force, surface tension, abrasive pinning force, and viscous resistance on dynamic wetting were analyzed. A dynamic contact angle model was established incorporating tool rotational speed, abrasive mesh number, and rough-surface slip effects. Experimental observations of dynamic contact angle evolution validated the model, with errors ranging from 7.67% to 12.28%. Bone micro-grinding experiments further examined the effects of grinding parameters on temperature. The results showed that grinding temperature was jointly governed by tool rotational speed and droplet dynamic wetting state, with dynamic contact angle and temperature exhibiting consistent variation trends. These findings clarify the connection between coolant wetting dynamics and thermal responses and provide a theoretical basis for understanding dynamic wetting on bionic tool surfaces and supporting temperature control during high-speed bone micro-grinding.