Tham khảo tài liệu 'handbook of industrial automation - richard l. shell and ernest l. hall part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | operation. The only consistency is that the material must follow the specific 1 2 3 routing. In these applications the APB can not only handle the physical moves between cells but can manage the storage of WIP that will develop between cells as a function of intercell variability. In most APBs the use of closed system replenishment rules provides an automatic kanban that throttles the system from having a runaway cell. As a free side effect however these systems can be tuned by the addition of free totes extra totes in the system for use between cells . These free totes provide some internal slack to the strict kanban control allowing cells to operate more smoothly in the presence of brief interruptions in the planned continuous flow. For example one cell may produce a product that is placed in an empty tote and delivered to the next cell for the next process operation. To perform the first cell s function it needs raw materials and an empty tote in which to place the output to be transported to the next cell. The second cell may remove the product from the tote process it and place it in a finished product tote for delivery to a packaging station for shipment. The empty tote created is then sent back to the first cell for replenishment. Between each operation the loads may need to be stored to prevent work buildup at the workstation that may make the station inefficient. Then when it appears that the station will be able to accept the next load the system needs to get it out to the cell before it is needed to prevent idleness. The flow of product from cell 1 to cell 2 and so on is balanced by the back flow of empties to the sending cells. If a backup stalls one of the cells the backflow stops which in turn stops the forward flow of material. This provides for a self-metering system that needs little control logic to keep all cells operating in a balance with the total system s capacity. The ability of the system to keep running in lieu of single cell failures is .
