Size Effect‐Driven Dynamic Cutting Force Prediction in High‐Speed Dry Milling of Plain‐Woven <scp>CF</scp> / <scp>PEEK</scp>

ABSTRACT The plain‐woven carbon fiber reinforced poly‐ether‐ether‐ketone (CF/PEEK) composites have the advantages of melt processing performance and excellent mechanical properties compared with traditional thermosetting prepregs. However, their cutting mechanisms are unclear, which could cause machining defects. Therefore, we presented the size effect in their high‐speed dry (HSD) milling, which is driven by the material's intrinsic structural characteristics. Based on the size effect, three innovative theoretical foundations are then produced: impact effect, specific surface enhancement effect, and three‐phase enhancement effect. These foundations clarify the cutting processes of plain‐woven CF/PEEK, including bending, stretching, shearing, impacting, pressing, delamination, and bouncing. Based on this insight, a high‐precision HSD milling force prediction model of plain‐woven CF/PEEK has been established, achieving a remarkable 90.1% accuracy rate. This model elucidates the causes of surface defects through the lens of the size effect. The model discusses the change of material properties and includes two extreme fiber orientations: 90° and 0°. It has strong adaptability and scalability, which can adapt to more complex fiber weaving conditions and wider fiber orientation angles. This model clarifies the cutting mechanisms of HSD milling of plain‐woven CF/PEEK and has great potential in controlling its machining defects.