With reference to the research findings in the multi-product Hybrid system, a large kanban size often leads to the result of higher average fill rate, and lower average manufacturing lead time. Contrarily, a smaller kanban size need more frequent machine set-up, thus the non-productive time is increased significantly. In other words, for a larger kanban size situation, the productive time in normal working hours can be maximized, and the factory may probably benefit from savings such as the reduction of labour hours in overtime production, and energy. However, a fill rate of over 100% is not desired. Therefore, the kanban size needs to be controlled within limits.