Some companies have already reached the limits of the traditional manufacturing model, in other words the Manufacturing Resource Planning (MRP II) model. This means that, if a company and its competitors have achieved the same goals - in terms of customer service level or on-time deliveries - the company needs to find other methods of improvement in order to be more competitive from a manufacturing point of view. Also, because the continuous improvement philosophy is now a common rule in the manufacturing environment, when a company has reached a limit it needs to find a solution to progress further.