Bat algorithm for designing cell formation with a consideration of routing flexibility

Cellular manufacturing system (CMS) is an approach that can be used to enhance both flexibility and efficiency in small-to-medium lot production environment. In cell formation, machines are grouped into cells based on their contributions to manufacturing process. Flexible routes have resulted in different machine sequences causing the changes in the movement of parts between cells. The movements in manufacturing shop floor lead to the efficiency of productivity relating to costs. Cell formation problem is classified into non-deterministic polynomial-time hard problem, of which the amount of computation required to find solutions increases exponentially with problem size. Solving this kind of problem by full numerical methods especially for the large size problem can be computationally expensive. The objectives of this paper were to describe the application of Bat Algorithm (BA) for designing cell formation aiming to minimise inter-cell part movement with a consideration of routing flexibility and investigate the appropriate setting of BA parameters that have an effect to the solution quality. A cell formation designing program was coded in modular style using a general purpose programming language called Tcl/Tk. The computational experiment was designed and conducted using ten datasets, in which the number of machines in each cell is either equal or unequal. The statistical analysis on the experimental results suggested that the population size and the number of iterations have statistical impact on the quality of the solutions obtained.