A Mathematical Programming Formulation for Cost-oriented Multi-manned Assembly Line Balancing Problem

Multi-manned assembly line balancing problems are usually occurred in plants producing large-sized high-volume products such as automobiles and trucks. In this paper, a cost- oriented objective function is presented for a multi-manned assembly line balancing problem. This kind of objective function may be used to balance final assembly lines of products in which manufacturing process is very labor intensive. A mixed-integer mathematical programming model is proposed to solve the problem optimally. The proposed formulation has been used to solve some small size problems by considering both time-oriented and cost-oriented objective functions. The experiments show that, given the same precedence graph of multi-manned assembly line with a same cycle time, two different optimal solutions can be actually found when switching from time-oriented to cost-oriented objective functions, and vice versa. This difficulty increases the complexity of the cost-oriented multi-manned assembly line balancing problems with respect to the multi-manned assembly line balancing problems addressed in the literature.