An Approach to Integrate Product and Process Design Using Augmented Liaison Diagram, Assembly Sequencing, and Assembly Line Balancing

Concurrent engineering is a product development approach in which engineers simultaneously design products and processes to improve customer satisfaction, enhance product quality, and reduce product costs. While various design methodologies have been proposed to support concurrent engineering, development of a systematic methodology that comprehensively integrates product and process design is still an ongoing research need. Traditional design for assembly (DFA) has been extended to concurrently design subassemblies and assembly sequences; however, the optimum assembly sequence depends on the efficiency of the assembly line and how assembly tasks are assigned to workstations without causing extensive idle time. This study extends past approaches in the concurrent design of products and processes by integrating assembly line balancing, assembly line design, and sensitivity analysis of assembly line design in addition to assembly line sequencing. In particular, this study proposes an approach to simultaneously design products and processes by integrating (1) a liaison diagram augmented with additional information on the type of liaisons (e.g., screw fixing, snap fitting, or contacting) to find stable subassemblies and corresponding assembly tasks, (2) assembly sequencing to generate all feasible assembly sequences that satisfy requirements for stable subassembly, (3) assembly line balancing to identify all possible assignments of tasks to workstations and to find corresponding cycle times and utilization, (4) assembly line designs that include the types and number of assembly lines for each product design, and (5) sensitivity analysis to evaluate the robustness of the assembly line design.