Order release is described as an essential decision function and a core parte of WLC (Missbauer, 2009). It occurs when orders (jobs) are released into the shop floor for processing. The concept behind controlled release is to release orders selectively, at the right moments in time, to improve shop performance. An order release mechanism is used, in combination with a pre-shop pool, to determine the moment and the orders to release into the shop floor. Releasing a set of orders is only feasible if it does not violate workload norms. Therefore, the orders generated by the planning system or arriving directly from customers over time are gathered in the pre-shop pool and are only released if they fit workload norms, usually defined in hours of work, of the required capacity groups (e.g. work centres) by the order’s routing. This means that the decision to release an order is based on its influence to the current shop floor situation. It is also based on the urgency of the order, i.e. orders are considered for release accordingly to a planned sequence.