Abstract: Whisker-reinforced titanium matrix composites are widely used in aerospace, vehicle transportation and new energy fields because of their excellent properties such as high specific stiffness and strength; however, due to the material anisotropy, defects are easily generated in conventional hole-making processing, which restricts their mass promotion and application. To this end, a new technological process of low-frequency torsional vibration assisted helical milling (LFTVAHM) is proposed, and the cutting force model is further derived by combining the motion characteristics of low-frequency torsional vibration and the processing characteristics of helical milling; on this basis, the experimental study of TiBw/TC4 composites is carried out to verify the rationality of the cutting force model. The model simulation shows that the maximum average cutting force of end face resultant force decreases by nearly 13.05% and 13.64% respectively compared with conventional helical milling when the torsional vibration tangential feed is the same as the tangential feed per tooth. Experimental studies show that, the low frequency torsional vibration helical milling helps to reduce the defects such as exit/entry burrs, hole wall scratches and crushing, and can effectively reduce tool wear; compared with conventional helical milling, the hole wall roughness is reduced by 36.29%.

Key words: TiBw/TC4 composites, low frequency torsional vibration, helical milling, cutting force model, hole quality