Ultrasonic lubrication assisted milling of CFRP: Elimination of fiber pull-out

Conventional machining of advanced materials is commonly faced with some difficulties like low surface quality, delamination, and fiber pull-out. Therefore, a variety of approaches are represented to improve this process. In this study, different cooling and lubricating methods (dry, water, oil, and MQL) plus ultrasonic vibration are applied to analyze the milling of carbon fiber reinforced plastic composite. The aim is the reduction of surface roughness and the area of fiber pull-out. As a result, it was seen that water and oil method decreased the area of fiber pull-out, while they increased the surface roughness, due to the generation of chemical reaction with workpiece material. The best result was achieved when the MQL method was coupled with ultrasonic vibration where the surface roughness was reduced up to 55% compared to the conventional milling with other lubricating methods. The positive effect of ultrasonic vibration on surface roughness was more than fiber pull-out area. Therefore, if only the elimination of fiber pull-out is desired, the MQL method is the best method, but if the surface roughness is also the target, then the combined method of MQL with ultrasonic vibration is the best method.