Integrated Design of Robotic Grippers for Pre-shaped Uncured Composite Compounds

The increasing demand for lightweight automotive frames is pushing toward adopting composite materials and automating the related manufacturing and assembly processes. Carbon Fiber Sheet Molding Compounds, CF-SMC, enable custom-shaped car body parts fabrication through a single-step compression molding process. Nevertheless, conventional manual stack-up impacts productivity since it is the operation required to enable the compression molding. Robotic manipulation of the pre-shaped uncured composite stacks can relax the continuity between these two phases. The handling process requires dedicated grippers to keep the deformable composite stacks within the shape deviations required to fit on the compression mold. To this aim, a two-stage integrated approach to design the robotic grippers is presented in this work. Bounded by the maximum allowed deformation to fit the mold, the first stage returns the grasping pattern, that is the optimal grasp point map. The second stage aims to identify the lightest stiffer frame for the gripper. A Computer-Aided Design platform is adopted to integrate the two phases of the method. A car body panel is the use case selected to implement the design steps described and demonstrate the feasibility of the proposed approach.