An Augmented ε-Constraint Method for a Multi-Model Assembly Line Balancing Problem with Parallel Workstations and Zoning Constraints

This paper develops a 0-1 integer-programming model for multi-model assembly line balancing and equipment selection problem. In the investigated model, parallel stations are allowed under zoning constraints. Under zoning constraints, assignment of different tasks to the same workstation may be forced (positive zoning constraint) or may be forbidden (negative zoning constraint). There are two objectives for the investigated problem: (1) Optimizing the number of workstations over the assembly line and (2) Minimizing the total equipment costs. An augmented ε-constraint method is proposed to solve the investigated problem. To illustrate effectiveness of the proposed model, a numerical example is conducted. Results show the performance of the proposed model.