Assembly sequences, assembly constraints, precedence graphs

In this paper, the authors present a critical discussion on relations between assembly constraints, assembly sequences and precedence graphs and a method to generate precedence graphs from any given set of assembly sequences. It is demonstrated that it is generally impossible to encompass assembly constraints for any product into a single precedence graph but that it is possible to encompass them in a precedence hypergraph as long as no some soft constraints have not been used to produce the assembly sequences. When soft constraints like clusters of components or early realisations for some tasks are used, several precedence graphs are required and the proposed method does not apply.