Synergistic Lubrication Effect of Texture and Copper on Cutting Performance for Broaching Tool

Abstract The broaching process is a heavy-duty and highly efficient metal-cutting technique. The heavy load encounters significant thermal and mechanical stresses on the tool during broaching, resulting in considerable friction within the tool–chip contact area. The friction adversely affects both workpiece quality and tool life. To address this issue, laser technology is utilized in this study to create three distinct textures on the rake face of the broach. Subsequently, an innovative rotary covering device is developed to cover the solid lubricant (copper) to both surfaces and grooves of the cutting tool. A broaching test is carried out to evaluate the impact of different textures and copper on-chip deformation. The findings demonstrate that employing a stripe-textured broach reduces the chip deformation coefficient by 16.1% compared to its nontextured counterpart. The tool surface covered with copper reduces the chip deformation coefficient by 7.7%. Copper not only reduces surface defects but also forms a lubricating film during cutting operations, thereby serving as an effective solid lubricant. The synergistic interaction between texture and copper enhances heat dissipation during cutting processes, consequently reducing temperatures within the tool–chip contact area. The temperature reduction alleviates plastic deformation in localized regions of the workpiece, resulting in narrower burrs. Therefore, using rotary friction for covering copper onto the rake face of a broaching tool represents a straightforward yet cost-effective strategy for optimizing frictional conditions and enhancing cutting performance.