There are many ways to schedule orders through a shop. Companies enlist everything from simple, visual signals to integrated, highly functional computer systems. All of these have their place. I am a proponent of the "simpler is better" approach to most things. Therefore, let me offer some simple production scheduling techniques.
1. Empty space. This is probably the simplest production trigger. By consuming items, users create empty space. When the supplying operation sees the empty space, whether it is an empty floor, shelf or pallet, it is a signal to produce the item that has been consumed. It's simple and effective, but this trigger has limitations. For one, the supplier and user of the parts must be in close proximity, or it is likely that the "empty space" signal will be missed.
2. Storage bins in a downstream operation. When a part storage bin at a downstream operation, such as assembly, is depleted or reaches a predetermined level, a replenishment order is generated. Such a system is intended to assure an uninterrupted supply of parts to the user. The quantity of items in the bin is based on the usage rate of the part and the re-supply time required. The size of the bin is determined by the quantity and size of parts. Some companies size a bin to hold as few as a day's worth (or even a few hours' worth) of parts, while others sizethe bin to accommodate larger quantities. The decision comes down to the reliability of the re-supply process. If parts are readily available, the risk of stockouts is lessened, and the bin size can be reduced. It is a simple technique, but it does require ongoing monitoring of the bins in the downstream department.
3. Markings on a wall or other vertical surface. Items such as flat cartons, sheet metal, wood products and containers of material can be stored along a wall and replenished by means of a visual signal. One such signal is a horizontal marking on the wall. A marking is set at a point where the material needs to be reordered. When this line becomes visible because material has been taken away, this is a signal that more material is needed. A line at a higher position on the same wall can indicate the maximum amount of material to be brought in. In such a system, exposing the reorder line initiates action. To make the reorder process as simple as possible, a preprinted reorder card or form should be attached to the wall at the reorder line. Once the line is exposed, anyone can take the necessary form and initiate the replenishment order.
4. Using totes. Tote pans can serve not only to carry and store components, but also to schedule replenishment of parts. If using totes to schedule production, it is important for information—including part number, reorder quantity and part user—to be marked on the tote. Some companies color-code totes by user department so they indicate the final destination of parts at a glance. Others use the information on the tote to indicate whether it is full or empty.
5. Schedule boards. A schedule board, whether it's an electronic billboard, a pegboard or a white board, will show what needs to be produced. Schedule boards come in many varieties, but each communicates the parts that are needed, how many of each are needed, and when they are needed. Schedule boards can be color-coded. For example, a board may contain cards with different colors on each face. One color will indicate that a part needs to be made. When turned over, the other color indicates that the part is in process. At a glance, you can see the status of each part on the board. Color-coding can also be used to indicate parts that should be grouped together and run at the same time.
Using a simple, visual scheduling system may make it easier to manage your shop.