In this stage, a release mechanism is used to determine the moment and the jobs that are actually released into the shop floor. When a job arrives at the pre-shop pool or when a job completes an operation, workload is updated and the pool is inspected in order to select a new job for release (see Fig. 1). Only those jobs for which the planned release time falls within a specific time limit are candidates for release. In this simulation study, the time limit was setto ‘‘ infinite’’ . This should improve the possibilities for load balancing within the release procedure (Land, 2006).