Minimizing the assembly cycle time on a revolver gantry machine

摘要

In printed circuit board (PCB) manufacturing the revolver head gantry machines are nowadays popular because of their flexibility, accuracy and high speed. The operation control of this kind of machines includes, for example, selecting the nozzles into the revolver, assigning the component reels to feeder slots, and determining the pick-up and placement sequences of the components. We consider in this article the feeder assignment and the pick-up and placement sequencing problems. Unlike to some previous literature on these problems, we suppose that each component can be picked up by a nozzle of a certain type, only. For the feeder assignment problem a new heuristic is given and tested against four existing algorithms. The proposed heuristic considers the types of the r nearest neighbors of each component on the PCB and assigns component feeders close to each other according to the closeness of the component types on the PCB. The experimental tests are performed using two data sets based on realistic PCBs. The new heuristic outperformed the previous methods with 3.4% faster placement times. For determining the pick-up and placement sequences four rule-based algorithms are introduced and their performances evaluated. The best two of these construct the sequences greedily around the placement position of a starting component, which is selected in turns as the component nearest to each corner of the PCB.