Multiple-part cyclic hoist scheduling using a sieve method

The paper proposes an algorithm for generating optimal cyclic schedules of hoist moves in a printed circuit board electroplating facility where transportation of parts between workstations is performed by a computer-controlled hoist. The objective of the scheduling problem is to maximize the throughput rate. Unlike many previous algorithms which consider 1-part cyclic schedules, the proposed algorithm provides an exact solution for the more complicated case of r-part cyclic schedules where r>1. The algorithm is illustrated with numerical examples comparing 1-part and multiple-part optimal schedules.