I was having a chat with someone about ‘batching’ the other day, and wanted to point them to a short and simple post I wrote a few years ago that I thought would assist…so I looked for it…and couldn’t find it…and then realised that I’d never published it on this blog…so here it is:

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I wrote a post a bit back entitled One at a time please. In it, I attempted to explain (using my washing up at home¹) about the problems caused by doing things in batches, and that we should strive to shift our processes towards ‘single piece flow’.

This is such an important point that I thought that I would put forward another, hopefully more obvious, example.

Right, here goes:

What do you see here…

…yep, we had two fancy coffee machines in our last works kitchen.

If you were to watch people using them you would note that it is rare that they are both being used…but it does happen…so having 2 machines helps cope with the variation in our demand for a coffee (with spikes in demand unsurprisingly occurring Monday – Friday at around 10:30 and 15:00)

These machines need regular cleaning. I think, from my observations that this is performed weekly.

Cleaning

How about this picture?

Yep, this is what happened when they were both being cleaned.

We used to have a cleaner that liked to come in at around 10:30 (not such a good time really…but that’s a different story), open up both machines and then proceed to perform his cleaning steps one-by one for both machines. Something like this:

• Take out both sets of waste drawers, empty them and put them by the sink
• Take out both drip trays, empty and put them by the sink
• Open up both coffee hoppers and fill them
• Open up both creamer hoppers and fill them
• Open up both sugar hoppers and fill them
• Clean the pipes and connectors of both machines
• Wash and dry the waste drawers and drip trays for both machines
• Put everything back together for both machines
• Close the front drawers of both machines
• Wipe the outsides of both machines
• …and done. Nice job.

This takes some time…and what can’t happen whilst this is being done?

No one can make a coffee! (or hot chocolate or mocha or …..name some other weird drink made from permutations of powder)

What’s the purpose of the machine? To reliably make (good) coffee as and when someone wants one.

A change in cleaner

I noticed one day that we had changed our cleaner. I also noticed this:

Oh yes! She does exactly the same steps as the earlier cleaner…but she does it one machine at a time.

Now, for those die-hard ‘economies of scale’ fans out there:

1. There is hardly any time difference between the two cleaning approaches; BUT

2. We can all still make coffee whilst it’s being done!!!

Even better, she concentrates on one machine at a time (in a state of flow), likely making sure that all is okay with it, potentially causing her to think far wider than just repeating a set of standard steps.

So there you go: a short and simple example of the sense in reducing batch sizes as and when we can 🙂

Anyone for a coffee?

Footnotes

1: My earlier post: If this is the first time you’ve read about batches then please do read my earlier post  – it goes into more detail.

There was one among you who, in response to this earlier washing up ‘batch to flow’ post, spent quite some time explaining to me exactly how they emptied their dishwasher, specifying how they had experimented with which items of cutlery were best held between each digits. Nice! You know who you are…Tom 🙂

2: On cleaners: I don’t know why the cleaner changed or why they adopted their different approaches and I make no judgement on either of them. I just really like being able to get a coffee whilst the machines are being cleaned!

3. Simple, and complicated: I know that there are all sorts of batches ‘out there’ (whether temporal or quantity based)…and I know that there are constraints that need to be understood and worked with (you can’t usually just remove, or even reduce, batch sizes – you have to look at the ‘why’)….but the desired target condition of ‘single piece flow’ can be used as a vision to experiment towards, whatever the nature of your batch.