How to Create a Yamazumi Chart
Step 1: Collect Data
Before creating a Yamazumi chart, if you have not already, you will need to collect data. You must first understand the flow of the process from start to finish and list out each operation or task in the order it happens. This will form the basis of the sequence of tasks that will appear on the X-axis of the chart.
Next, for each operation listed, measure the cycle time (how long the process takes). This can be collected with direct observation using a stock watch or with digital tools that collect data from machines.
Step 2: Categorize Activities
Following the data collection, the next step is to break down the cycle time of the activities in each step into VA, NNVA, and NVA.
Value Add analysis Pie chart
Value-Add Activity:
Value-added activities are those that directly contribute to meeting the customer’s requirements. The customer finds these steps valuable and is willing to pay for them because they directly transform the product or service.
Examples include:
- Machining a part to customer specifications
- Assembling components into the final product
- Painting a product in the customer’s chosen color
Necessary Non-Value-Added Activities (NNVA)
Necessary Non-Value-Added activities do not add direct value to the product or service but are currently required to support the value-added steps under the existing process configurations. These are often due to technical limitations, regulatory compliance, or current organizational structures and should be minimized whenever possible.
Examples include:
- Quality inspections to ensure the product meets quality standards
- Moving materials between workstations due to layout constraints
- Setup times for machinery
Non-Value-Added Activities (NVA)
Non-Value-Added activities are operations that take time, resources, or space but do not add any real value to the product or service from the customer’s perspective. These are considered waste and should be eliminated.
Examples include:
- Waiting for materials to arrive or machines to become available
- Excess inventory that ties up capital and space
- Rework due to defects in earlier stages of the process
By categorizing activities into these three groups, you can more accurately assess where your process can be streamlined. This categorization also informs where to focus your continuous improvement efforts: eliminating NVA activities where possible, reducing NNVA activities, and ensuring that VA activities are performed as efficiently as possible.
Step 3: Create the Yamazumi Chart
Most people use Microsoft Excel or a similar spreadsheet tool to create Yamazumi charts. These tools are flexible and allow you to input your data, create stacked bar charts, and adjust the visual presentation.
Specialized Software
There are also specialized Lean Six Sigma software tools available that can help you create more sophisticated charts with additional features for analysis.
Excel Method
Creating a Yamazumi chart in Microsoft Excel involves several steps to properly visualize the process time for each step, along with the categorization into VA, NNVA, and NVA activities.
If you would like to follow the process but do not have data, feel free to download our demo data to practice the next steps: Demo data download.
Here’s a step-by-step guide on how to create one:
Step 3.1: Data
Before you open Excel, make sure you have your process data ready. You will need:
- A list of each step in the process sequence.
- The time taken for each step, broken down into VA, NNVA, and NVA.
Step 3.2: Table of data creation
Open a new Excel workbook and set up your data in columns:
- In Column A, list the process steps.
- In Column B, list the value-added time (VA) for each step.
- In Column C, list the necessary non-value-added time (NNVA).
- In Column D, list the non-value-added time (NVA).
Step 3.3: Insert Stacked Bar Chart
- Highlight the data you just entered.
- Go to the ‘Insert’ tab on the Excel ribbon.
- Click on ‘Bar Chart’ and choose ‘Stacked Bar.’
You should now have your Yamazumi Bar chart, and you can use the tools in Excel as needed to change the styling, etc.
Step 4: Analyze the Chart
Now that you have the chart, the next step is to analyze it and identify opportunities to improve the following:
Cycle Time Variations
Look for variations in cycle time across different steps. Steps that are significantly longer might indicate bottlenecks, while shorter steps might indicate areas where operations are highly efficient.
Waste Identification
Examine the proportion of non-value-added time in each step. Large segments of NVA time are opportunities for waste reduction.
Workload Balance
Assess the distribution of work. In a balanced process, steps should have relatively even cycle times. Discrepancies may suggest that some operations are overburdened while others are underutilized.
Step 5: Optimize the Process
Use the insights from the Yamazumi chart to make informed decisions about process changes. This might involve redistributing tasks, combining steps, or changing the sequence of operations.
Continuous Improvement
The Yamazumi chart is not just a one-time analysis tool but part of an ongoing process of continuous improvement. After making changes, the process should be reevaluated and a new chart created to measure the impact of those changes.
By going through these detailed steps, you will not only create a Yamazumi chart but use it as a dynamic tool to drive process improvement in your organization.