Improve assembly line balancing by changing cycle time

Assembly line balancing belongs to a type of combinatorial optimization problems. It is affected by many factors. Thus some assembly lines are difficult to obtain solutions with high balancing under the fixed cycle time. A mathematical model is presented to improve the balancing of assembly lines by altering the cycle time. Considering the slack time and smoothness, an objective function is formulated under the fixed cycle time. Based on the objective function, a new slack time function and smoothing index function combining a penalty factor are developed. A sample is used to compare assembly line balancing under the fixed and variable cycle time and demonstrates that the solution under the variable cycle time is optimal. The proposed method provides flexibility for decision makers to balance assembly lines with low balancing.