Production lines have fluctuations. Sometimes production takes longer, sometimes shorter, than the average. This makes the line balancing tricky. Besides using a simple buffer between workstations, it is also possible to adjust capacity. Other approaches I have written about include the rabbit chase and the bucket brigade. Here I present a variation of the bucket brigade called „One Up One Down.“
In lean manufacturing – or in fact, in any kind of production system – you have to solve problems. Depending on the problem, you may need a creative solution and have to access the wisdom of the crowd. For this I have a workshop structure that I frequently use for problems that have lots of different options. Let me show you my workshop structure with which I’ve had quite good results.
This is the second post of a two-post series on shop floor etiquette (first post here). I find this a very necessary post, as I have way too often observed visitors to the shop floor lacking manners (and occasionally, I may have lacked manners myself 🙁 ). Hence, please do not treat this post as optional, but try to incorporate it into your daily shop floor work. Being accepted on the shop floor is crucial for any successful change on the shop floor.
There is often a distinct lack of appreciation and good manners toward shop floor employees. Yet, lean manufacturing happens on the shop floor. Not in Excel, not in PowerPoint, not in meeting rooms. As such, you need to become part of the shop floor in order to change the shop floor. For this, you need the support and goodwill of the people on the shop floor. The first step to getting their support is to have good shop floor manners. Due to the length of the post, I have divided it into two posts. These two posts will give you some guidelines on how to behave on the shop floor. (The second post is here)
In my last post, I started to show the main reasons why EPEI leveling with a fixed repeating schedule so often fails (for details on EPEI leveling, see Theory of Every Part Every Interval (EPEI) Leveling). This post continues with more reasons and also gives some advice on how to reduce the damage or even increase its chances of success. It also has a suggestion for a test to determine if your system is ready for leveling.
Again, there seems to be a lean religion that claims that putting up a leveling box will lead to salvation. Well, Lean is not a religion or magic. Lean is hard work, and you actually need to understand what you are doing. Just copying something without understanding is a good way to fail, especially with leveling.
In my last post I presented the EPEI leveling pattern (also known as EPEC, EPEx, Heijunka, fixed repeating pattern, or simply leveling). While in theory this approach looks pretty solid, in my experience it rarely works in practice. In fact, most of these types of leveling that I have seen were complete rubbish. They were a dog-and-pony-show to please management at the expense of performance and shop floor efficiency.
Furthermore, lean manufacturing seems often to be confused with a religion. People believe that if you put up a leveling box your manufacturing system will have salvation. Well, Lean is not a religion. Lean is hard work, and you actually need to understand what you are doing. Just copying something without understanding is a good way to fail, especially with leveling.
I occasionally watch the reality show Undercover Boss, where top executives work undercover in their own companies. Over and over again I see these managers making the same mistake: They have no understanding whatsoever of what is really happening on the front lines. It is a typical case of not going to the shop floor often enough, or in lean speak, no genchi genbutsu (Japanese for „go and see“). So, <dramatic voice> Why do bosses all make the same mistake? Will they ever learn? Will you enjoy this post? See for yourself in the post below! </dramatic voice>.
Standard wisdom for creating a good material flow is to use FiFo lanes (First in, First out). In other words, the first part that goes into the line should also be the first part that comes back out. As such, FiFo lanes and its big brother, Supermarket, are essential for any lean material flow. However, some rules of wisdom can be bent and others can be broken. Here are the top five cases when NOT to use a FiFo lane.