I have written a lot about leveling and the value of fluctuation in previous blog posts. In this post I will show quantitatively what the benefit of reduced fluctuations is for Denso, part of the Toyota group and a supplier to many other car makers too.
Inventory
On Leveling and Fluctuations—How Does Toyota Do Leveling?
My last two posts in this three-post series on leveling talked about fluctuations and leveling in general, and the challenges and costs associated with leveling. In this last post I will go into greater detail on how Toyota does its leveling. Because Toyota does this actually quite well.
On Leveling and Fluctuations—The Downsides of Leveling
In my last post I gave you a brief introduction to fluctuations and leveling. And, I already hinted that there are two downsides to leveling: properly set up it handles only fluctuations coming from upstream, and—what is rarely talked about—there is an increase in inventory and/or waiting time to decouple the fluctuations in leveling. The second one especially is widely ignored or even vehemently denied in industry, but it is definitely there. Let me show you!
On Leveling and Fluctuations—Introduction
Leveling (or Japanese heijunka) is a common topic in lean manufacturing. Leveling combats one of the three evils in manufacturing: unevenness or fluctuations (in Japanese mura). While reducing fluctuations is an excellent goal, it is unfortunately not free, and there is significant effort not only for implementing and maintaining the leveling system, but also on the way the fluctuations are reduced. While everybody talks a lot about the benefits of leveling, very few talk about the cost. This may be one reason why so many leveling systems fail. Let me show you the hidden not-so-nice side of leveling.
Real vs. Planned Data in Pull Systems
Pull systems like kanban and reorder point are a cornerstone of inventory management and fluctuation reduction in lean manufacturing. The production is managed based on ACTUAL consumption. Theoretically, it is also possible to include expected but not yet actual consumption. In this post, I will explain to you the concept behind it and why I think it is a bad idea…
On the Benefits of Putting Your Processes Close Together
Putting your processes closer together in manufacturing obviously saves space. However, there are many more benefits of putting processes closer together. Let me give you a run down of the benefits:
Steps Toward One-Piece Flow
One-piece flow—while often defined differently—is one of the True Norths in lean manufacturing. Get your material flowing! In theory that is easy. In practice, however, there are many obstacles standing between where you are and where you want to be, also for one-piece flow.
What Are the Advantages of One-Piece Flow?
One-piece flow is strongly connected to lean manufacturing. It moves each product to the next stage as soon as it is completed at the previous stage in the value stream. This brings lots of benefits. While I have written about one-piece flow before, in this post I would like to go into detail on the beautiful benefits of it.