A Yamazumi Chart, a Yamazumi Board, and is also known as the operator line balance chart. It is a visual tool that can be used in lean production/lean manufacturing to assist with continuous improvement as well as cell design. It allows you to visualize the various work elements included in each step of the task at hand and compare them to the takt time that had initially been predetermined.
The literal Japanese translation of “Yamazumi” is to “stack up.” Thus a Yamazumi chart is a stacked bar graph of the company activity times within a particular task or process.
What is Takt Time?
The demand rate or a limit given by your customers in how much you are able to produce is referred to as "takt time".
To calculate the Takt Time of a particular task, you divide the total amount of available work time by the average number of parts that the customer has required.
In other words, the Takt Time is essentially the speed at which your business should run. The faster the time, the higher the amount of inventory and profits, whereas a lower time indicates that you have failed to meet the demands of the customer. When creating your work cells and process for a particular task, the Takt time is one of the most crucial factors you should take into consideration.
In What Ways is a Yamazumi Chart Beneficial?
The purpose of creating a Yamazumi Chart is to be able to determine which areas, as well as employees, are facing levels of work that might be causing them anxiety or stress thus causing them to fall behind.
It also helps to point out others that are experiencing down time or “idle” time that can assist with the task thus lessening the burden of the operators mentioned above.
It helps to balance out the workload as realistically any business can only operate at the speed of the slowest link in the chain of the overall workflow. Your yamazumi chart can help you to determine the weakest links in the task at hand.
You can also use a yamazumi chart to help differentiate between the value adding and non-value adding processes which then allows you to determine how you can cut production and other costs by eliminating those non-value operations which are slowing down your production costs and times.
As well, you can use the Takt time to determine the peaks and lows of your overall manufacturing process. You can draw a line across the light of the Takt time and once you have balanced the workload the time will be under the initially allocated Takt time.
Japanese workers are using a yamazumi chart in the picture to the left. Not everything needs to be digital.
Timing Work Elements for Yamazumi
To properly balance a work cell, you will need to know the demand take (aka the Takt time) as well as how much time is required for each task to be completed. In olden days, a supervisor would determine the workspace by observing the workers overall time with a stopwatch to arrive at the standardized times required to complete a task. With today’s technological advances, it makes far more sense to utilize video equipment to record the production process as opposed to a stopwatch and then later the entire team can sit as a whole to analyze the manufacturing process.
Yamazumi Chart Example
The Takt Time on the Right is the total time available to be spent per individual process. Each process is broken up into value added, non-value added and necessary operations. You add each time for all the operations together and can compare against the takt time. Assuming that each of these operations is happening concurrently.
How can a Video Recording of the Production Process Assist in the Creation of a Yamazumi Board?
As with other lean production tools, a yamazumi board will involve the entire production team in the overall analysis of the task, as well as in how to make improvements. As mentioned above, a video of the time required to complete a process can be analyzed by the entire production team as well as the managerial staff to determine the Takt time needed for a particular task.
Through analyzing the different tasks and people involved in the production process, you can also oversee how each process is being conducted and how each step affects the overall product production. You gain time to choose and fine-tune those processes and steps that are the best means of production for a particular task.The process should then be allocated, or broken down, into small steps that can be easily timed and managed, as well as being labeled as other value-adding or non-value adding elements.
To determine this, you would have to time the following tasks:
- Time it takes to for the employees to reach the production floor/machinery (non-value added time)
- The time needed to select/input the work component (non-value added time)
- Time required to return to the workstation (non-value added time)
- Time required to affix necessary components to the necessary equipment (non-value added time)
- The time it takes to operate the essential equipment (value added time)
Determining the Factors with a Yamazumi Chart?
You can indicate many factors from studying a Yamazumi chart. For instance, if the overall operation time takes longer to complete than the Takt time, you need to distribute the workload more evenly. As well, you can more efficiently review non-value added tasks and refine, reduce and remove those that are deemed unnecessary or inhibit the value added factors.
Ideally, your Takt time should be consistent overall. It is a wise practice to create your work cells to incorporate such instances an unforeseen event or increased productivity times, such as seasonal demands, etc. A good rule of thumb is to create a workflow diagram based on a normal operation as well as one for busier production times or those times when you might be short staffed. It is better to be prepared for a variety of scenarios to keep your Takt time at a steady rate over time using a yamazumi chart.