What is a Yamazumi Chart and Why You Should Use It

The first step to becoming productive is becoming aware of what you spend your time on. This is also true when it comes to business processes. If too much process time is spent on wasteful activities, you can expect productivity to suffer. Wasteful activities also increase costs, decrease employee satisfaction, and negatively impact the customer experience. Having a way to see where wasteful activities are occurring in the process can help businesses eliminate them. This is where a Yamazumi chart can help.

What is a Yamazumi Chart?

Yamazumi in Japanese means “to stack up.” A Yamazumi chart is a graph that shows the cycle time of each task in a process step displayed as a stacked bar graph. It’s a tool to visualize machine and operator cycle time to assess performance. It’s also a good indicator of variation among workstations that do the same thing. Variations, or mura in Japanese, result in muda or waste in the form of delays and excess inventory. It was used early on by car manufacturing companies, like Toyota, for their line balancing and workflow optimization activities.

A sample Yamazumi chart is shown below where the x-axis shows the workstations or operators and the y-axis shows the cycle time per workstation. Each block in a stack represents a task in that workstation or by that operator.

Another variation of the Yamazumi chart looks similar to the first one but this time, the x-axis shows the different process steps. Tasks are still represented by blocks in each stack that are color-coded to denote which ones are value-adding from the non-value-adding.

Yamazumi charts usually have the takt time horizontally highlighted within the graph. Any workstation, operator, or process time that goes beyond the takt time is immediately a candidate for optimization. At a glance, you would know how long a task takes up from your process. It’s a simple yet powerful tool that pinpoints where the problems are occurring.

Benefits of a Yamazumi Chart

Here are 3 benefits of using a Yamazumi chart and why you should consider using it for your manufacturing business.

Reduces Costs Due to Time Wastage

By having a visual tool that shows how much time is being spent where, you can easily see where time is being wasted, such as bottlenecks and delays. Eliminating non-value adding tasks not only decreases costs but brings back the time that could be spent on more value-adding activities or investments.

Aids in Line Balancing

A Yamazumi chart can help you quickly spot what processes are overburdened or underutilized. It’s also helpful when there is a need to rebalance the line or rearrange the process. This usually happens when takt time changes. A Yamazumi chart can also help you compare performance between workstations or machines. By having cycle time available across all your lines, you can see which ones need to be optimized. Achieving a more balanced line will help you achieve predictability and ensure customer demand is met consistently on time.

Helps Establish a Kaizen Mindset

Being a visual tool, a Yamazumi chart can be an effective motivator for employees to improve the process. And as they religiously measure and evaluate their performance, continuous improvement, or kaizen, is much more achievable. A Yamazumi chart also helps companies ensure that all their process tasks add value to their end goal. Challenging the current process and thinking of ways to further improve it to add more value can be instilled in the company’s culture with the aid of visual indicators such as a Yamazumi chart.

Waste Elimination with a Yamazumi Chart

Process waste can be seen in all business processes. To achieve optimal levels of productivity, waste must be reduced, if not eliminated. A Yamazumi chart becomes a warning signal for business teams to spot and combat wastes by targeting where they occur in the process. It’s also a tool to monitor and compare process performance against targets. Furthermore, it can be a tool to show improvement opportunities and push business teams to find ways to do the work more efficiently.