Creep feed grinding of narrow-deep-groove with monolayer cBN abrasive wheels: Grinding performance and surface integrity

The creep feed grinding process is extensively utilized in precision machining of narrow-deep-groove (NDG) components. However, the perpendicular geometry between the side and bottom surfaces of NDG results in distinct surface integrity characteristics across different surfaces. This study investigates the material removal mechanisms and the distribution of surface integrity across the bottom, transition fillet, and side surface of NDG components during the creep feed grinding. A model for the maximum undeformed chip thickness (MUCT) across different grinding zone of the NDG is established. Key parameters, including grinding force, grinding temperature, morphology, roughness, microstructure, microhardness, and the residual stress, are investigated. The MUCT decreased from the bottom to the transition fillet and became a lower value at the side surface. The lowest grinding temperature of 153.1 °C was recorded on the bottom surface, whereas the highest temperature of 297.3 °C was observed at the side surface. The grinding temperature on the side surface is 22.4% to 31.7% higher than that on the bottom surface. Severe plastic deformation was observed on the bottom surface, resulting in a work-hardened layer with a thickness of 52.5 μm due to high grinding forces induced by larger MUCT. Compressive residual stress was generated on both the bottom and side surfaces, with a greater magnitude on the bottom compared to the side surface. The bottom surface residual stress value is 68.4% to 78.9% higher than that of the side surface. These findings provide deeper insights into multi-mechanism physics of grinding, thereby facilitating the precision manufacturing of high-reliability NDG components.