One of the basic analyses applied on production lines is Yamazumi analysis. The greatest benefit of this analysis, used during workload balancing, is that it sets out value-adding and non-value-adding work clearly and explicitly. I believe this analysis must be done especially while one-piece flow is being set up. In this way the facts are brought into the open, and the points that need to be focused on are determined.
The word Yamazumi means "to stack" in Japanese. The work steps are shown stacked on top of one another for each station. Thus a way of using it emerges that is the same as the literal meaning of the word.
Toyota uses the Yamazumi chart to show workloads visually, to reveal non-value-adding work steps, and to achieve workload balance easily. Because the non-value-adding workload is laid out visually, all employees can focus on eliminating these workloads.
The best way to prepare a Yamazumi chart is to record the workstation on video while it is operating and then work on that recording. After the recording, each step is examined one by one on the chart. All the movements that are made are separated into those that create value and those that do not. The steps are placed, stacked and scaled according to duration, on a workstation basis. Value-adding operations are colored green, and non-value-adding operations are colored red. In this way non-value-adding operations are identified visually. At the same time Takt Time is marked on the chart, which creates the opportunity to compare it with the current state. Thus unbalanced workloads that run longer than Takt Time and cause the line to slow down come into the open. With the work to be done, these jobs can be distributed to the other stations, or an improvement can be made by working on how the job is performed. In this way the labor productivity of the line increases.
