Computer-aided assembly planning for the diemaking industry

The paper describes a CAD-based approach to some management tasks related to the manufacture of stamping tools for car body parts. The proposed method generates assembly plans for draw dies and trim/pierce dies from their design information. Die assembly is a highly constrained process including a variety of part handling, measurement and surface finishing operations. As such, it escapes some critical assumptions underlying most generative planning methodologies in literature. Such complexity is faced through a comprehensive description model of the assembly process, which represents the space of all feasible operation sequences for any allowable die configuration within a predefined domain. Once a specific configuration has been retrieved from solid and surface CAD descriptions of die parts, the assembly model is instantiated into a graph-like data structure, which include only applicable operations and their precedence constraints. An instance describes operations at a sufficient detail level to support time estimation, process documentation and production scheduling. A prototype software tool derived from the assembly planning method has been tested in a real industrial context, in order to evaluate its potential impact on the efficiency of die manufacture.