A roughing/cementing robotic cell for custom made shoe manufacture

In the shoe manufacturing process, in order to attach the upper with the corresponding sole, it is necessary to 'scrape' a thin layer of material off the upper surface so that glue can penetrate the leather and adhere; an operation called 'roughing'. This paper describes the design and the implementation of an innovative robotic cell for roughing and cementing of shoe uppers, which operates at the moment in a pilot plant for custom-made shoe production. The small size of the production lots, as required by customization, and the accuracy needed to follow the complex 3D roughing paths, require a considerable degree of flexibility to minimized setup time. In order to meet these severe requirements, the robotic cell, described in this paper, integrates CAD-CAM generated tool paths with the use of a force controlled head, mounted at the manipulator wrist, which allows real-time adaptation of the trajectory in order to ensure continuous and stable contact between the tool and the shoe to be processed, regardless, to a certain extent, of the inaccuracies in the path specification. The paper describes the development details involved in the design of the cell, with a special emphasis on the active head and the overall control architecture.