A sequential consideration for assembly sequence planning and assembly line balancing using the connector concept

In an ever-changing era, fast responses in the research and development (R&D) of products should be made to satisfy the various needs of customers. The sequential consideration for assembly sequence planning and assembly line balancing can contribute to shrinking the gap between design and manufacturing. The so-called assembly sequence planning refers to a task in which planners arrange a specific assembly sequence according to the product design description as well as to their particular heuristics in assembling all the components of a product. Assembly line balancing is concerned with how to effectively arrange every assembly task so as to reach the highest efficiency and the shortest idling time in the total assembly line. In this study, connectors equipped with assembly engineering information (combination, direction, tool, and cycle time) serve as the basic units to replace the traditional method in which only parts are taken into consideration. Connectors can be defined as the basic units that offer limitations to components, and when these units are combined, they will perform the required functions. Under the constraints of connector-based precedence graph, similarity between connectors is used to arrange the assembly tasks. When the result meets the cycle-time requirements and the types of stations to which the connectors belong, the arrangement of stations based on the assembly sequential order is processed. Genetic algorithms are proposed to solve the arrangement of connectors and the selection of stations. Two examples illustrate how to apply the model in practical cases.