Quantifying hole quality through geometry accuracy and surface qualities in rotary ultrasonic machining of carbon fiber–reinforced plastic composites

摘要

Rotary ultrasonic machining has been approved as an effective and efficient hole making process for carbon fiber–reinforced plastic composites. Hole quality plays an important role in assembling carbon fiber–reinforced plastic compo-nents and can be affected by the carbon fiber reinforcement structures. In this study, experiments are conducted toassess hole quality in carbon fiber–reinforced plastic composites with three carbon fiber reinforcement structures underdifferent combinations of machining variables. Hole quality is quantified through geometrical accuracy (perpendicularity,cylindricity, and hole diameter) and surface qualities (delamination and surface roughness). Results show that the highestlevel of interlacement among yarn of plain woven structure induce the highest level of compression to the workpieceand the largest amount of additional material removal, leading to the largest perpendicularity and hole diameter. Theworst fabric integrity of unidirectional structure generates the largest amount of non-uniform material removal on themachined surface, resulting in the largest cylindricity. It is also found that compared with woven structures, unidirectionalstructure is more likely to induce push-out delamination due to its smaller critical energy release rate. The lowest con-stancy of the fabric in twill woven structure leads to the largest surface roughness.