Q 438. What is a Yamazumi chart? How can it help improve the process efficiency? Explain using an example

 

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Yamazumi Charts are basically stacked bar chart , These charts are very useful in identifying multiple stage wise impact on single category to identify the root cause. These charts help user to identify key pain area within process which require high attention.Generally Yamazumi charts are used to analyze cycle time of each process steps, Takt time calculation or access performance break up of macchine or Operator. It is useful in balancing work flow of the process and prioritize key area of bottleneck. It is also helpful in identifying Value adding activity and non-value adding activity in process flow.Yamazumi charts gives warning signal for to identify key waste to eliminate or reduce. It is generally useful in projects like changeover time reduction, SMED/ECRS activities, Lead time reduction , Station wise waste analysis for Yield related projects etc.

Yamazumi means to “to pile” or “to stack up” in Japanese. These graphs help visualize process performance through a stacked bar graph for Value Add and Non-Value Add activities.

 

Simplifying process steps and eliminating non-value add activities are critical contributors to improve performance of the process. Yamazumi charts help with visualization of the process steps, variation between operators and/or workstations. This method was used by Toyota for Line balancing and workflow optimization.

 

Here I am using a simple example of Pizza Order Delivery (using Yamazumi chart for Process Efficiency):

We have 60 Orders per Day to deliver, Each day of 6 Hours Productive Time.

Takt Time: (6*60)/60 = 6 Mins

Steps of creating Yamazumi Chart:

·        Y axis for Time and X axis for Process Steps

·        Below Hypothetical Example for X axis: “Current state/As is state”

 

Process Steps	Process Time (minutes)
Step 1. Order Received	7
Step 2. Dough Preparation	15
Step 3. Toppings	5
Step 4. Oven	3
Step 5. Retrieve and Slice	7
Step 6. Package	5

 

·        Draw Graph with Takt time as Secondary Axis (6 Mins)

·        Graph below represented by blocks for Non Value Added Activity for sub processes

 

 

Process efficiency using Yamazumi Chart:

 

Yamazumi charts help visualize Waste. Being able to differentiate value added activity versus nonvalue added activity encourages organization to challenge current way of working and think of ways to improve.

 

1.      It is used for simple easy visualization to show the problem areas and highlight bottlenecks. Any process step that goes beyond Takt time is immediately a candidate for Optimization.

2.      This graph has also been used for Line Balancing i.e. to balance work content between the processors/workstations.

3.      Integrate and Visualize results of Lean Technique ECRS (Eliminate, Combine, Re-Arrange and Simplify) using Yamazumi charts

-        Eliminate - Eliminate Waste and Non-value add activities. In the example, all process steps optimized by eliminating waste

-        Combine – Combine steps to optimize the flow. Step 3 & 4, as well as Step 5 & 6 combined

-        Re-Arrange – Remove bottlenecks by re-arranging the steps. Step 2 has 2 processors to avoid bottlenecks and process orders faster

-        Simplify – Make the process flow and work easier

Process Steps	Process Time (minutes) – Current State	Process Time (minutes) – Post Improvements
Step 1. Order Received	7	5
Step 2. Dough Preparation – Dough Making	15	6
Step 2a. Dough Preparation – Pre heat		5
Step 3. Toppings	5	6
Step 4. Oven	3
Step 5. Retrieve and Slice	7	6
Step 6. Package	5

 

 

 

Yamazumi charts can be used to motivate teams and leadership towards Continuous Improvement and driving process efficiency in a systematic way.

 

 

What is Yamazumi Chart?

The Yamazumi (Japanese for to stack up) chart is a Lean tool that is used in Business Process Improvement. It displays the source of the cycle time of a process. It is a stacked bar chart. It helps in improving the process efficiency through the optimization of the process.

Each process is plotted on the X-Axis. Each task of the process is either designated as Value Add or Non-Value Add or Non-Value Add Step that is necessary and is individually stacked up on a bar chart. The Y-Axis measures the mean cycle time.

A Value-Added Step is any activity that changes the form, fit, or function of the material or to meet the customers’ requirements or an activity that the customer is willing to pay for. It is done right the first time. A Non-Value-Added step is a waste, adding no value to the customer but raises cost and increases the time. NVA steps include defects, errors, omissions, setup, inspection, and the 7 causes of waste. (TIMWOOD). Required NVA steps are a business, employee, or process necessity such as accounting, payroll, and inspection.

A target cycle time which generally is the mean cycle time is plotted and the line balancing of the process is undertaken. Besides line balancing the Yamazumi chart can also be used for waste reduction. Line balancing can be done through rearranging, deleting, or combining tasks/processes.

How Yamazumi Chart improve process efficiency?

The Yamazumi chart is a tool that helps to quickly visually identify the cycle times, VA and NVA components of each process, and the potential areas of bottle-necks. An unbalanced line leads to bottle-necks at the processes with higher cycle time.

The visual identification of the process helps in balancing the line and adjusting the cycle time of each process closer to the takt time. This would improve the throughput and hence process efficiency.

Example

After line balancing, the throughput has improved from 51.4 units per hour to 64.3 units/hour

References: http://www.leanlab.name/what-is-the-yamazumi-chart

Yamazumi chart is a simple visual management tool that has graphical summary of a process which help identify the opportunities for initiating Kaizen events. It is good indicator to see the variation among workstations that do the same set of activities. Yamazumi is a Japanese term which means to stack up so in this chart each process activity is individually presented in a stacked-up bar chart. The steps can be seen as separate blocks within the bar for each operator and it becomes easy to focus on the steps which take longer or operators who take longer. The steps can also be categorized as VA/BVA and NVA and at a quick glance optimization opportunity can be arrived at.

The Y axis represents the cycle time and X axis represents the operators doing the task or processes

Using Yamazumi Chart we can graphically present the step wise time, from here we can easily recognize that process4 is the bottle neck and it has non value added time presented by the red section, if we worked on reducing the time spent there, the bottle neck will be solved and the line will meet the takt time.
Similarly on the below exampple, Operator # 2 has exceeded the Takt tim annd has about 35 econds of NVA time whch if worked upon would help reduce the time for Opertor #2 and remian within Takt time. 

Benefits:
•    Reduces delay
•    Reduces cost associated with time
•    Helps in line balancing
•    Establish improvement mindset
These would overall help in improving efficiency of the workshop/process. 
 

 

About Yamazumi Chart

 

In general, Yamazumi word was originated from Japanese, and it means “to stack up”.

In the world of Lean & Six Sigma, the projected process data is seen as stack bar chart (Yamazumi) to understand the process pain parts (or) areas observed slowness (or) for the visibility of unusual steps (or) non-value adding steps.

Yamazumi charts helps in showing a way to identify unwanted activities. (or) It's another tool to enhance the waste elimination in the process.

 

Explanation of Yamazumi Chart with an Example

In an Organization, The Digital Products Unit, “Director” has raised a concern with the "Vice President" of Procurement Shared Services about the several delays in order delivery by the suppliers. Specially with IT categories.

Surprising part is that, the budget/cost are getting approved immediately when the scope of work and planning are in place. Few orders are getting On time, and some are delayed for months, and it is impacting the production. Digital unit doesn’t have visibility of any activities after the cost approval of the project. Eventually this has become a bigger complaint on delayed orders.

VP of Procurement wanted to have a general body meeting with the Director, Procurement Managers, and the Quality Manager to address the issue and narrate the current state of process and possibilities/various areas to improve the efficiency of the process from the IT Need to Delivery.

Hence, the VP requested the quality manager to look for the historic events of all the procurement transactions with respect to IT needs. Also advised to produce an “Eloquent 1 Page Visualization” of the data with issues.

The Quality Manager after collecting the historic data, has produced below Yamazumi Chart, and found interesting investigations about the delays of some orders.

 

Based on Yamazumi Chart in the general body meeting, below observations were discussed: -

-        Order delays are only with New Suppliers.

-       Number of days processing and progressing each step varies for different categories of IT needs i.e. Application Development has less turnaround when compared to Infrastructure & other categories.

-       Adequate time is required to Securely run RFP/RFQ with potential new suppliers, organizing DEMO’s and selecting the right supplier to fulfil the IT need.

-       Various Approvals (legal, supplier addition, background checks) are necessary to onboard new supplier to the Company to ensure/avoid/zero any kind of risks & complications.

 

Meeting ended with: - The Identified Red One’s in Yamazumi Chart were shortlisted for further study and process standardization.

The Director and the VP has appreciated the quality Manager for this kind of visualization and enlightening the process activities, days it took at each phase, for various categories with New & Existing Suppliers.

 

Thus, The Yamazumi Chart has helped in projecting full picture of IT Procurement from “Needs to Delivery” of all categories.

 

 

Supplementary Details: -

In the recent days it is observed that the analysis, investigations & projections are expected instantaneously with availability of wide varieties of data.

Here, Tableau is very helpful in providing the Stack charts/ Yamazumi Charts.

Below is a sample picture extracted from Tableau depicting the various sales of IT brands and their price categories at various regions.

 

Yamazumi is a Japanese word, means Stack-up! Yamazumi chart is a stacked bar chart that shows line balancing of cycle time, workloads b/w number of operators typically in an assembly line/work cell. Yamazumi chart can be used to one or multiple products in the assemble line. Toyota used this chart to visually present the series of task and facilitates work balance long with elimination of NVAs

 

If productivity to be improved you need to be aware of where your time is going and what are the value-added steps and non-value added steps, if you fail to identify the VA and NVAs then productivity will suffer. To identify the VA’s and NVA’s Yamazumi chart would be helpful.

Yamazumi chart is kind of stacked bar chart and it graphically represent the processes for optimization purpose. “Yamazumi” is a Japanese word and  can be translated as stack up. To create Yamazumi chart, we have to select a process and calculate the time taken by value added, non- value added and necessary activities in the identified process. Yamazumi chart then shows these activities in a form of stacked bar. This can also be compared with Takt time. If the bar height is more than the Takt time (target value), the process steps can be rearranged , improved or deleted to optimize the process.

 

The chart helps in business process improvement by visually showing how the processes are overloaded (stacked bar height more than the Takt time) or underutilized. This way teams can perform line balancing analysis and identify areas to do Kaizen.

Yamazumi is a very famous chart when it comes to identifying bottlenecks in the process. The best answer has been provided by Chaitanya. Other answers are worth a read for the examples quoted.