The Yamazumi chart is a bar chart used in the companies which apply the logical Lean to identify the workloads divided between a number of operators, typically of an assembly line or a production cell.
This allows to facilitate the assignment of new activities and to identify the removal of any tasks with no added value.
Yamazumi can be used in various ways: if the Yamazumi diagram is associated with the Takt Time, this diagram allows a direct visual and balance workloads among operators. In the axis of ordinates are workloads divided for all the operators of the analysis object; all these activities are shown stacked in columns corresponding to different activities of each operator. In the axis of ordinates depicts the time that each operator dedicated to the workload to be played; as upper limit is placed on Takt Time: if the “column” of an operator exceeds this limit, it means that his workload does not comply with the timetable and then or trying to reduce activities that add no value, or means serving a further operator in order to comply with the Takt Time.
This technique has the advantage of being a visual tool very simple and intuitive. If it is hung near a production line it allows workers and managers to immediately see where they originate delays and remedy, being able to thus increase the competitiveness between departments and be able to trigger continuous improvement.
At a time when there is the need to rebalance the workload due to an oscillation of the question or because, for example, the application of continuous improvement has led to a reduction of the working cycle, it is very simple to revise the division of tasks among workers. This type of diagram can also be used in kaizen perspective to understand where a process can be improved.
For example, we can point to a particular color activities that, in our opinion, have no added value and go to analyze them more carefully, if only to reduce the impact temporally. The areas that, on the contrary, are those that provide added value will be those on which focus more.
We can also identify a third color of assets that represent real waste that must be eliminated.