Just in Time (JIT) is a powerful tool in lean. However, it is not an easy tool. Using it without understanding the requirements can quickly make things worse. I have written about related topics before, but during the COVID-19 pandemic, Just in Time was often blamed for a lack of material, usually by people who do not understand how just in time works.
This last post of my series looks at fluctuations that originate downstream from your location. In other words, how to reduce fluctuations originating from your customer. Granted, this often is the most difficult one, as you usually have not so much influence over your customers (unless you have a monopoly). Let’s have a look.
Fluctuations can also originate within your area of responsibility. In my previous post, I looked at how to reduce fluctuations coming from upstream. In this post I look at your shop floor. Using the source-make-deliver structure, this post is about reducing fluctuations at “make.”
This post will list a number of tools that can help to reduce fluctuations. They can reduce fluctuations in the material flow, including its inventories and the durations and lead times. Since reducing fluctuations (mura) is an underlying important idea throughout lean manufacturing, a lot of tools can help. And, depending on how you interpret tools, this list is not even complete.
This post looks at how to reduce fluctuations (mura) in manufacturing. It is a continuation of the previous post that looked at why fluctuations are so bad. Be warned, tackling fluctuations is often a tedious task that never ends, but it one of the important fundamentals for lean manufacturing. After all, the more stable a system runs, the more efficient it is. Leveling is one major method to reduce fluctuations that focuses on the production schedule. Line balancing is another one that focuses on the work content.
In a previous post I wrote about the relation between utilization, fluctuation, and waiting time, and its approximation by the Kingman formula. Let me show you a quick and easy dice game where we simulate a supermarket checkout to let participants experience the effect of utilization, fluctuation, and the (worse) combined effect of both.