Identification of variation sources for high precision fabrication in a digital twin context

Paper in proceeding, 2020

The aerospace industry is increasing its focus on fabrication in manufacturing, foregoing large castings to instead assemble and join smaller parts into final products. This increases the total amount of geometrical variation introduced during the production process, since the unique variation from each individual part can add to a propagating effect putting the final assembled product outside of tolerance limits. Geometry assurance and variation simulation has traditionally been applied as a part of the design process to develop robust manufacturing concepts that are as insensitive as possible to variation. A concept for geometry assurance has been proposed where variation simulation is conducted for each individual assembly using real measurements from incoming parts, making it possible to make adaptive adjustments to production parameters to optimize results. It is however not feasible to measure and simulate every aspect of the process. This paper provides a summary of relevant sources of geometrical variation for a high precision fabrication process, based on input from a fabrication process in the aerospace industry. Variation sources are analyzed and discussed from an industrial perspective, putting them in the context of an actual fabrication process as well as in the context of digital twins for geometry assurance.