A Lean Enterprise is centered on the concept of flow. Flow is one of five key Lean Principles identified by Womack and Jones in their book Lean Thinking. They stressed that you need to make value flow. It was this creation of flow that would make it possible to eliminate waste. When material and information flow continuously, there is less waste in the system. This is true by definition. If there were a lot of waste, material and information would not be flowing.
The first step is to focus on the analyzing the value stream. Find out why the inventory is necessary and what purpose the work in progress is serving, then reduce the amount of things that are waiting around. If frequent machine breakdowns are the problem, then focus on the machine and reduce the stoppages. If the quality is unstable, then repair the equipment and standardize the workers’ processes to reduce variability. If people are holding inventory because they are afraid of running out of parts, then talk with the leader of the area and decide how many parts should be held. As the ability of the area improves, the inventory can be reduced accordingly. Focus on the foundation of the value stream. Keep reducing the amount of things waiting around and get closer to flow.
Once the amount of things that are waiting is reduced this will mean that you have less time to solve problems that occur in everyday operations. Problems will appear faster, and also will affect other areas faster. This is actually the desired result. Many things in the company will now have to speed up to prevent production stoppages. Once you get enough strength, you can continue to reduce the amount of inventory.
Creating flow gets production and engineering involved. People have to come up with improvement ideas. Kaizen involves every employee - from upper management to operators. Everyone is encouraged to come up with small improvement suggestions on a regular basis.
Once you get to one-piece flow then you can make a Kanban for the line and start with a downstream pull system. As the name suggests, creating flow is about making and moving one item at a time (or the smallest batch size possible) through a series of uninterrupted steps, with each step in the process making exactly what is requested by the next step while never knowingly passing poor work forward.
Flow is often not actively pursued because people feel it is more realistic to eliminate waste from work processes, introduce workplace organization through 5S or apply other lean tools. This is a mistake – it turns out that, when you introduce flow into any process, problems (i.e., opportunities to deliver customer value) become vividly apparent and demand immediate attention. Introducing flow can be a bit scary, but it can also sharpen your focus on improvements that will be immediately felt by your customers!
A consistent flow of work is essential for faster and more reliable delivery, bringing greater value to your customers, team, and organization.