The value stream is the totality of all specific actions required to develop a particular product. As already mentioned, this can be a good, a service or increasingly a combination of the two.

Consequently, it is necessary to identify and understand the entire value stream. This step in Lean Thinking, is often overlooked by companies and leads to enormous amounts of Muda (jap. Waste).

If one examines the process in terms of its components, one will inevitably be able to divide each process step into one of the following three categories:

  1. Value-added: The activity directly serves the delivery of the customer's added value and is necessary for the desired performance
  2. Not value-creating, but necessary: While this activity does not serve to directly create value, it is necessary in a supportive manner for a value-creating activity. For example, commuting times that cannot be eliminated with today's technology.
  3. Waste: These activities do not provide any added value for the customer. One example is unnecessary waiting times or rework due to unclean work

In the above-mentioned activities, the aim is to optimize the value-adding activities, reduce the necessary activities and eliminate waste in its entirety.

Source of error: Lack of overall process understanding

A good example of value stream mapping and optimization is given in the book "Lean Thinking" by James P. Womack and Daniel T. Jones. Pratt & Whitney, the largest manufacturer of jet engines, once examined the processes used to manufacture their various engines. They found that there was a lot of waste in the step between the supplier and the processor of the raw materials. The supplier was supplying titanium and nickel in a form and with a surface finish that the processor of the materials could not use as optimally. In the process of manufacturing the individual parts for the aircraft engines, more than 90% of the expensive raw materials were thrown away as scrap.

How could such enormous waste have gone undetected for years in such a highly complex and highly technological industry as the aviation industry? The answer is simple: The companies involved in the supply chain never communicated their requirements or wishes to the other suppliers. Just as little were the suppliers aware of each other's workflows. Once this lack of communication was discovered, Pratt & Whitney was able to significantly reduce the cost of its engines. Among other things, the supplier of the raw materials supplied the materials to be processed in a form that was more suitable for the manufacturer of the aircraft parts.

Direct communication instead of structural change

The story described shows that lean thinking must go beyond the company itself. In process optimization and value stream mapping, it is important to consider all suppliers and customers. Subsequently, one demands that these communicate with each other. Only in this way can everyone respond to the needs and requirements of the next link in the process chain. The entire process, from conception through production to delivery to the end customer, is the observation horizon of the value stream analysis.

When considering the entire value stream and its optimization, a misunderstanding often arises. This refers to the need for a new body to coordinate the participants. The introduction of a control body would cancel out the actual added value of the value stream analysis and optimization. This is because the understanding of the overall process and the direct communication of the requirements would be missing. It would also massively restrict the learning process of the companies actually performing the work.

In order to make a company and the associated upstream and downstream ?lean? and efficient, there must therefore inevitably be a shift in thinking towards better B2B communication. The value stream must be transparent for everyone in order to be able to discuss possible optimization potential.