A planning tool for line balancing, sequence planning and employee deployment in high flexible mixed-model assembly lines to prefabricate modular living units – a case study

To effectively address customization needs in building production is of importance to receive contracts in off-site construction, which consequently means that the number of variants to be handled in prefabrication lines increase. New approaches in off-site construction aim to better cover the need of customization by increasing the flexibility of mixed-model assembly lines for module production. However, this potentially increased flexibility in the prefabrication plans needs to be appropriately considered in various planning tasks at the tactical and operational level. Consequently, this paper addresses the balancing of high flexible mixed-model assembly lines, the sequence planning of modules, the employee deployment planning and material requirement planning. An algorithm for a planning tool was developed and tested to support these tasks to provide suitable plans for operations managers, giving them the ability to manage and control the productivity of high flexible mixed model assembly lines. The test results revealed the generation of suitable solutions from a line balancing and sequence planning perspective but showed the need for further research to enable the application of outcomes from employee deployment planning not just at the tactical but also at the operational level. Cycle times calculated for available projects show a line efficiency of up to 70% and propose worker station and task reallocation in order to improve worker’s utilization and the number of specific workers needed. This research consequently contributes to enable a higher level of customization of products off-site construction but at the same time facilitating a high level of productivity and efficiency of module prefabrication lines.