A lot of industries use continuously moving assembly lines. This is common in automotive, but also in many others. The challenge is to manage the fluctuations. You cannot decouple using inventory; you can decouple only long-term fluctuations using capacity, while all other fluctuations are decoupled using time. This is the first blog post of a series digging deeper into how to handle or NOT handle fluctuations on continuously moving assembly lines. This first post looks at the effect when workers move among different stations.
Fluctuation
The Benefit for Denso of Reducing Fluctuations
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.
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.
Toyota Change Point Management: Henkaten
Henkaten is an approach by Toyota to deal with changes in their manufacturing system. It is one of the lesser-known words of the lean vocabulary. Often translated as “change point,” it is about managing a change. However, there is no magic behind yet another Japanese word. It is all just the basics like most methods in lean manufacturing: attention to details, standards, and visual management. Let me show you!
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…
How to Reduce Part Variants
In my last post I looked at how to reduce product variants, and the inevitable conflict with sales. In this post I will look at how to reduce not the number of final products, but the number of part types that go into the final product… and here you often have a conflict with product development. However, like the reduction of the number of final products, this reduction in fluctuation has significant benefits for the company.