This is an excerpt from the book "Five Minute Lean", by David McLachlan - a wonderful book that blends teaching of the tools, culture and philosophy of traditional Lean with a modern-day Lean parable. You can get the whole book on Amazon here and enjoy your own copy.
Heijunka: Level the Workload when Demand Fluctuates
In a perfect world, we would know in advance what our orders or requests for service might be, so that we could have enough people or resources ready.
Unfortunately, in the real world, requests often come through in different amounts and at different times, with different items being requested. Most companies’ response to this is to either constantly be behind in orders or requests (while their customer suffers), or constantly have too much inventory or people in a desperate effort to meet demand, creating all kinds of waste (3.1).
We have already seen how to balance the Cycle times of our process with Line Balancing (3.4), but we can also balance our workload when demand fluctuates using Load Levelling, or “Heijunka”. By using information of previous orders (or demand), combined with information of upcoming orders (or demand), we can smooth things out considerably using the following techniques.
Let’s say a company regularly receives orders, for any type of item or service, for 100 items a week, but demand fluctuates from day to day (for example 40 on Monday, 20 on Tuesday, 20 on Wednesday, 10 on Thursday and 10 on Friday), we could use a small buffer of finished goods (like a Supermarket, 4.1) to respond to Monday’s high demand, then level production at 20 per day, meeting our 100 per week demand.
In Lisa’s case, if call volumes at the Shoe Emporium fluctuate from day to day, Lisa might get this information by checking the historical volumes from the last week, month and year. She might recommend having more people working on a Monday (a buffer, like the example above) who would assist in smoothing demand.
Figure 23: An example of Load Levelling, where daily demand fluctuates. We can use a buffer, or “supermarket” on Monday to meet demand, then smooth production at 20 per day.
Alternatively, we can also level the type of item we work on. Imagine a company has three types of products (products A, B and C), with daily demand being 20 for Product A, 10 for Product B and 5 for Product C, or a ratio of 4 : 2 : 1. Instead of simply lumping (or batching) the production of each item together at the same time or with the same operator, we can level it out so there is an even number being produced at all times, allowing us to respond to fluctuating demand more readily.
Figure 24: An example of Load Levelling, where the types of requests are different. Producing the Lean way, especially when we have one piece flow, we ensure there is an even number being produced at all times.
This is the type of thing that Lisa might use at the Shoe Emporium, if she got different types of sales and service requests by email. Instead of only one person performing one type of request, they can be spread across her team and ensure the requests are completed evenly instead of batching them together. This way there is less waiting while the one person completes their workload, and less chance of a single point of failure.
This is an excerpt from the book "Five Minute Lean", by David McLachlan - a wonderful book that blends teaching of the tools, culture and philosophy of traditional Lean with a modern-day Lean parable. You can get the whole book on Amazon here and enjoy your own copy.
Selected chapters from the story within Five minute Lean:
- Lean Parable – Where Lisa Makes a Change
- Lean Parable – Where Lisa Discovers a New Way
- Lean Parable – Where Lisa Performs a Balancing Act
- Lean Parable – Where Lisa Pulls the Trigger
- Lean Parable – Where Lisa Sets a New Standard
- Lean Parable – Where Lisa Becomes a Leader
Check out these selected chapters from the teachings within Five Minute Lean:
- Five Minute Lean – Go to the Gemba
- Five Minute Lean – Introduction
- Five Minute Lean: Glossary
- Five Minute Lean – Put it Together With Design for Ease of Use
- Five Minute Lean – Gather Direct Feedback and Indirect Feedback
- Five Minute Lean Summary
- Five Minute Lean – Eliminate the Eight Wastes to Improve Flow
- Five Minute Lean – Use Kaizen and Kaizen Events to Help Stakeholder Buy-In
- Five Minute Lean – The Power of Incentives – What is Measured and Rewarded Improves
- Five Minute Lean – Collect and Measure Feedback With the Net Promoter Score
- Five Minute Lean – Work Towards One-Piece-Flow (and Reducing Silos or Batching)
- Five Minute Lean – Implement With Agile for Fast Iterations and Feedback
- Five Minute Lean – Build in Quality with Error-Proofing and Autonomation
- Five Minute Lean – Create a New Standard Procedure and Checklist for Quality Control
- Five Minute Lean – Help Your Process Flow with Line Balancing
- Five Minute Lean – Organise Your Process with Five S
- Five Minute Lean – Use Feedback to Fix and Guarantee
- Five Minute Lean – Create a Pull System with FIFO, Kanban Triggers and Visual Management
- Five Minute Lean – Add Important Data to Your Map
- The Five Minute Catch-up