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.
Leveling
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.
Mixed Model Sequencing – Summary
Mixed Model Sequencing to manage different product types with different work content is tricky. This is now the twelfth post of this series. I knew it would be long, but I never guessed that it would be that many posts. This is almost a book (and will probably be part of a book in the future 🙂 ).
Mixed Model Sequencing – Complex Example Verification
As part of a much larger series on Mixed Model Sequencing, this post describes how to verify the sequence quality. It also describes how to determine the required buffer spaces to buffer against these fluctuations in workload. There may be some wiggle room here. Read on:
Mixed Model Sequencing – Complex Example Sequencing 2
In this seventh post on Mixed Model Sequencing, I will finish the sequencing of the more complex example with Product-Dependent Workload and Mixed Model Sequencing. This is now the tenth post in this series. I knew this sequencing topic was demanding, but even I am surprised how much there is to cover. Thanks for staying with me, and read on.
Mixed Model Sequencing – Complex Example Sequencing 1
Sequencing products due to different workloads of different products at different workstations is tricky. This is now the sixth post on Mixed Model Sequencing, and we finally start with our sequence! Wohooo!