What Does Production Flow Look Like?
A key part of implementing Lean Manufacturing into a Production area is understanding Flow; how parts move along the processes, between each workstation and what this looks like across the week and month. The future state value stream map has provided a vision for what the Production flow will look like, defining which parts of the overall production process can flow easily, which parts needs direction and which sections need the highest level of control.
Production flow comes naturally for continuous process manufacturing and the tools we use to orchestrated production don’t apply here. The tools we are looking at are best used for discrete manufacturing with varying batch sizes in companies where people are needed to move product from one location to the next to get them through the manufacturing process.
As with many of the Lean Manufacturing tools, the aim is to get 80% of the parts moving along, allowing the other 20% for things to go wrong or some unusual event to occur – this may be simply expediting one lot of parts to meet an urgent customer need or for a batch of trial production or product R&D. Variation does occur and needs to be allowed for and tackled with problem-solving (a topic for another time).
Ideal flow will be when processes can be linked together and balanced. This way a fixed amount of work in progress is built into the process. Stability and good visibility are needed to establish this type of flow. The ultimate example of production flow is a moving line, where each part of the process is balanced and moves in harmony. If something goes wrong, the entire process stops as it is all tied together. This is what we see in car manufacturing and other high volume manufacturing processes.
For many manufacturing processes, the dream of a moving line is too far into the future to think about. Over the next few weeks, we will look at first-in / first out lanes (FIFO), supermarkets and kanban systems to help control production flow.