A high-shear and low-pressure intelligent precision grinding system for complex-curved parts

Complex-curved parts made of superalloy, advanced ceramics, and other difficult-to-machine materials are frequently used in the aerospace field. The harsh environmental conditions place very high demands on their surface quality. Precision machining of the complex-shaped parts is facing great challenge. Furthermore, it is impossible to accurately control the contact state between the curved surface and the abrasive tool with the increased shape complexity, which will produce unpredictable grinding issues, e.g., surface scratches, grinding burns, and surface/subsurface cracks. To bridge the gap, a high-shear and low-pressure intelligent precision grinding system has been developed. A 9-axis motion which integrates a 6-axis industrial robot and a three-dimensional precision motion table is completed to adjust adaptively according to the shape of the complex-curved surface. A super elastic composite abrasive tool (SECAT) that attains high-shear and low-pressure grinding modes has been developed to improve surface quality. Its contact state with the complex-curved workpiece is kept stable by the closed-loop feedback of the 6-dimensional force signal. Experimental investigations of the newly developed system are demonstrated using the Inconel 718 alloy and zirconia ceramics workpieces. The surface roughness of both workpieces is quickly reduced to a nanometer level within several grinding strokes. Both the grinding efficiency and the surface quality are considerably improved.