A heuristic algorithm for minimizing total production time for a sequence of jobs on a surface mount placement machine

In the high-mix, low-volume environment faced by many electronics manufacturers, setup engineering techniques are becoming increasingly important for competitiveness. This is especially true in printed wiring board (PWB) assembly where assignment of components to machine slots is a very time-consuming task. In this paper the authors develop the intelligent slot-assignment algorithm to sequence a group of PWB assembly jobs on one placement machine with the objective of minimizing the total production time. The algorithm consists of two stages: the assignment stage and the reassignment stage. In the first stage, new parts are assigned on the machine with the objective of minimizing setup time; while in the second stage, parts are reassigned to different locations on the machine to minimize the runtime. The authors also demonstrate that the algorithm tends to produce job sequences which are close to the optimum.