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.”
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.
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?
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.
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 🙂 ).
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:
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.
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!