Having established the customer added value and identified and optimized the value stream, the next step of Lean Thinking follows: The value stream must be brought into a continuous flow. In most cases this step requires a complete reorientation of the way of thinking and the idea of efficiency!

We are all born with a way of thinking that wants to group activities and tasks into "functions" or "departments". Our minds assume that it is efficient to group and collect things. Because it seems to make it easier to manage them. Studies with small children have already shown that the vast majority of them divide a process according to the different process steps. An example of this is the folding, packing, labeling and gluing of a letter. First they fold all letters, then they pack them, and after labelling all the envelopes, they close them last.

This way of working and organizing can also be found in many companies. Because here too, activities are carried out in lots. In the paint shop of an automobile manufacturer, this means that all green parts are painted first, before switching to the red parts and finally taking care of the yellow parts.

The parties are employed by this type of production and the equipment is under full capacity. Accordingly, our common sense tells us that this is also efficient. But this assumption is fundamentally wrong! Studies have shown that this type of work and the division of tasks results in very long waiting times. After all, most products just lie around waiting for most of the time to be processed.

One step at a time

Taiichi Ohno, the developer of the Toyota Production System (TPS), attributes this kind of human thinking to evolution. He justifies it with the fact that humans evolved away from the hunter and lost the "one thing after another" way of thinking. In the course of Lean Thinking, however, this way of thinking must be actively suppressed. After all, the increase in efficiency through a continuous flow is enormous.

So one should not focus on the organization or the equipment. Production works better if you focus on the product and its needs. Only then are all activities, from the design to the provision of a product, in a continuous flow.

Probably the best known case of using a continuous flow is Henry Ford with his assembly line production. He managed to reduce the production time of the Model T by 90%. He only achieved this by running the steps of assembling the car in the right order one after the other. However, this Ford assembly line production was only intended for a large production volume, where each product requires exactly the same parts. Taiichi Ohno recognized the need for a production with smaller production volumes. For this reason, the TPS does not work with an assembly line production, but with production stations. Between these stations the product can be quickly moved back and forth. In contrast to the Ford production method, the TPS should also give the employees the possibility to stop the production. This gives them the opportunity to report or correct errors.

Obstacles in the rethinking process

The efficiency of this type of production can be easily proven. In companies where it has been introduced, the efficiency has immediately doubled. In addition, significantly fewer errors occurred.

It has been known for decades that this type of production is not as efficient as the production sequence in a continuous flow. So why do so few companies make use of it nowadays?

The most fundamental problem is that flow-thinking is counterintuitive. For most people it seems obvious that work should be organized in "categories". Because they think that this is the only way to be truly efficient. In addition, companies have often already invested a lot of money in special equipment to handle this method of working. This, of course, also speaks against the changeover to flow-oriented production.

The lean alternative is to redefine the work of companies and stakeholders. This should enable them to make a positive contribution to value creation. This is because they can focus on the actual needs of the end customer at any point in the value stream, thereby promoting the value flow.