Integration of measurement planning with aggregate product modelling for spacecraft design and assembly

Dimensional management captures key tolerancing attributes of a product at the design stage and manages dimensional variation during subsequent manufacture and assembly stages in a coordinated fashion. An essential part of dimensional management is the full integration of the measurement activity into the production process. This paper describes the use of aggregate product modelling (APM) as a vehicle for integrating dimensional management into complex product design and assembly. The motivation for this is to improve process flow and reduce process integration risk at major assembly levels. Based on the analysis of an aerospace assembly application, the link between the measurement strategy and the final measurement uncertainty of the finished product has been demonstrated clearly. Error propagation models were developed to quantify the contribution of different error sources to the overall uncertainty of a specific assembly process. The analysis could be applied to the whole design, assembly, and measurement process in a closed loop fashion, clearly illustrating the use of dimensional management in practice.