The changeover wheel is a visualization of a good changeover sequence. In this series of posts I will go deeper on how to use such a changeover sequence in planning your production sequence. The concept itself is simple, but there are still some pitfalls in using it. This first post looks deeper at generating a first sequence. My next post will then optimize the sequence, where we will also learn why you probably should not shoot for the perfect solution, but merely for good enough.
SMED
(EN) Changeover Sequencing under Duress: Problems with Make and Deliver
In my last post I looked at strategies to manage changeover sequencing if your supplier gives you trouble. Basically, you can sometimes reduce the damage by fine-tuning the prioritization (i.e., by using the limited raw materials to make the most important parts). This second post in this series looks at similar situations if your customer acts up, or if your own system makes problems. In other words, after discussing „source“ in the last article, we now look at the „make“ and „deliver“ part. Admittedly, some of the approaches are similar to the problems with „source.“
(EN) Changeover Sequencing under Duress: Problems with Source
Changeover sequencing helps you to produce more efficiently with smaller lot sizes, less inventory, and/or less changeovers. But despite a good changeover sequence, sometimes things blow up in your face. Your supplier does not deliver, your customer wants more than you planned, or your main process went belly-up and is waiting for repairs. In any case, something is forcing your hand and messing up your changeover sequence, or more generally your entire production sequence. What do you do? Well, depending on what happened, you may have options to mitigate the damage. This first post will look at mishaps originating from your supplier, and the next post will look at difficulties originating from your customer or even from your own system.
(EN) Replenishment Time Stability for Changeover Sequencing
Changeover sequencing is simply creating a production sequence that reduces the changeover effort. For example, in injection molding, colors are often changed from light to dark to reduce the cleaning effort. However, like all production sequencing (like leveling, lot sizing, prioritization,….), it adds to the replenishment time. Especially if you are using pull production, a consistent replenishment time reduces fluctuations, whereas an inconsistent replenishment time increases fluctuations and hence waste. But how can we get a more consistent replenishment time?
(EN) How to Prioritize in Changeover Sequencing
Changeovers take away time from production, and often require larger lot sizes as well. The best response would be of course to reduce changeover times, but this is a lot of work and may not always be possible. Another frequent option is to sequence the changeovers to reduce the overall changeover time. This post looks at a way to sequence production while also being able to prioritize production.
(EN) SMED – Creative Quick Changeover Exercises and Training
One popular approach to battle waste is to streamline changeovers. Changing machines from one setup to another is often a time-consuming exercise. Hence, in lean manufacturing, reducing changeover times is a well-known method for improving efficiency. This post will show a number of examples where these quick changeovers (also known as SMED) can be practiced in an unusual environment.
(EN) The History of Quick Changeover (SMED)
In the previous post, I explained the basics of a quick changeover. In this post, I will go through the history of quick changeovers (also known as SMED). It is quite interesting to learn how things have developed during the twentieth century. The next post will look at different, unusual ways to teach SMED.
(EN) Quick Changeover Basics – SMED
One popular approach to battle waste is to streamline changeovers. Changing machines from one set-up to another is often a time-consuming exercise. Hence, in lean manufacturing, reducing changeover times is a well-known method for improving efficiency. In this post, we will go through the basic approach of improving changeover time, also known as quick changeover or single minute exchange of die (SMED).