Teaching One Piece Flow

Teaching One Piece Flow. This teaching simulation shows the difference in Total Lead Time when there is batching versus when there is single-piece flow.

0. There is one item in this model: Item 1.

1. Add demand consistently. In this case, both Demand Blocks are set to a Constant of 1, ensuring that both lines get equal demand. This setup will help demonstrate the differences at the end. 

2. The Activity Blocks are the same between the two lines. The Activity Blocks labeled by 2b have a slightly longer Processing Time than the other Activity Blocks. This will cause a bottleneck before this Activity.

3. Wait for a Batch of 5. This Batch Block will batch Item 1 into groups of 5 before allowing it to move on in the process.

4. Unbatch all items. This Queue Block has a setting to Unbatch All Items, which is important to ensure that the subsequent Activity Blocks only work on each item individually.

5. Repeat the Batch and Unbatch process after the next step. This adds another round of batching to our process.

6. The second line does NOT have batching. By removing the Batching Blocks, we eliminate the batching requirement for the line.

7. Notice the difference in the Total Lead Time between the first and second lines. Total Lead Time refers to the time from item creation to entering that particular block. Since this is the last block, this is the total time through the simulation. In Process Playground, you can run the same simulation multiple times from the Run Menu. As a result, this output shows the mean across all runs (the Grand Mean) and the Standard Deviation between those runs.

Example models like this are great for explaining different lean concepts and showing their effects on the process. In this case, we have a significant decrease in time in the process when operating under the single-piece flow than when operating with batching.