Monday, July 07, 2003

Automatic Icemakers

Recently, I've tried to describe various ways to undersand what lean looks like. Here's another try.

Last Saturday, in yet another example of how grown men tend to forget just how old they are, I made a quick movement in a game that I used to be able to make easily. No more. I pulled a hamstring. I felt it pop. Oh no, down I went. Embarrassed. In pain. Unable to walk for a day. And with more time to sit and think than expected over the long holiday weekend.

Standard therapy for a pulled hammy is called RICE; Rest, Ice, Compression, Elevation. It is the "ice" part of this that hit me as another example of lean.

As I made and replenished ice packs to put on my hamstring, it occured to me that the automatic icemaker in the freezer portion of our refrigerator is a great example of a lean system. It uses a limited amount of inventory (filling the container) to satisfy the normal needs of a family. It makes ice only when ice is needed. It has an automtatic, simple, mechanical flapper that gives a signal to either make more ice or stop production. When demand goes up (thanks to the silliness of it's owner, for example) it cycles more frequently. When demand goes down (as in the winter), it cyles less. It converts a batch process (12 cubes per shot) via the small "finished goods" inventory into a flow process (take as many cubes as you want). It is properly sized. Our unit would be totally inadequate in a resturaunt. But, it works fine for a family.

All of this is perhaps obvious. But consider this.

The icemaker sits idle for much of it's life. It does not maximize efficiency. If the container is full, it simply sits. Isn't this a waste? Isn't this inefficient? Didn't I pay for that ice maker? Don't I want it to keep going, flat out?

No. What I want is ice. I don't want an efficient ice maker. All I want is ice. In the amount that I normally use, whenever I want it. And if it sits idle through most of the cold Indiana winter time, what do I care? I already paid for it. The incremental use of water and electricity is not important. I just want ice.

The icemaker is correctly sized. It does just what I want. When I want it. And sitting idle is just fine.

It is a great example of what a lean machine looks like.

I hope this is helpful. And do be careful of your hamstring. Feel free to forward to a friend. Email me

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