Tuesday, July 10, 2007

Zero Inventory is about more than just saving money on holding stock.

The ideal batch size is one.

When you order one shiny new blue automatic Toyota Corolla with air-conditioning and power windows (but without the sports bumpers or tinted windows) precisely one order for a blue automatic Toyota Corolla with air-conditioning and power windows (but without the sports bumpers or tinted windows) enters the factory.

In a perfect pull system this means:
- one more engine block gets poured
- one more automatic transmission sub-assembly is delivered to the final assembly line.
- precisely 875 M5 screws are delivered (ok I made up that number)
- when the blue car body goes barrelling down the assembly line, an air-conditioning unit is manufactured to arrive at the assembly line at just the right time.

To achieve anything approaching this level of synchronicity is a special kind of magic. But I want to talk about WHY you'd do it. Why not just make make 500 engines, 500 air-conditioners, 500 transmissions and sit back and wait for the orders to pour in.

Why go to all the trouble?

When you don't buy more from suppliers than you can manufacture you don't have to waste money to have stock lying around gathering dust. When you don't manufacture more products than you can sell you're not wasting your time making the wrong thing. That's easy, anyone can see that.

The Lean Manufacturer takes it further than that: they look at the process involved in getting there. They recognise that while taking ANY forwards action is commendable, true perfection is unattainable; and that this fact should be seen as a motivator to remain constantly vigilant in the face of recent success.

A Lean Manufacturer is agile, able to change pace or direction at the drop of the hat. At all levels, from corporate direction and new model design through to deciding how many car-seats are to be delivered this hour, plans are worked and reworked right up until the last moment. The LM'er is able to respond to market demand.

While there is very little room for error in the Lean factory these things do happen: when a fault occurs at one station the ENTIRE line stops and EVERYONE rushes to that spot to fix the problem immediately. By committing themselves to the Lean path the weak links are quickly rooted out and strengthened.

When a factory operates according to a true pull-system everyone can be confident that their effort is valuable. People won't bust their guts for 3 weeks straight cranking widgets that are just going to sit in some warehouse somewhere, those widgets are going to be in the customer's hand by the end of the week: guaranteed.

How does this relate back to GTD?

So, you've got a ToDo list. Well done. When you organised you don't waste time doing things that don't need to be done. Ok. That's the easy part.

When you take it further and start applying GTD you learn WHY you have that list, and how it makes your life easier:
  • your life will never be perfect, but the closer you get the more serene you will be. Every step in the right direction is great. Seriously, well done. Now you know that you can take that step: go take the next.
  • when you have all your Stuff totally zipped up and captured you're able to change projects instantly. You can finish what you're doing and go play with the kids, safe in the knowledge that you aren't leaving some vital unclosed loop unrecorded.
  • because you concentrate more on what needs to be done immediately you have more feedback on the doability of your commitments. What can look like an easy week's work on a ToDo list suddenly becomes 90 hours of cumulative Next-Actions! That's good information to have at the START of the week BEFORE it becomes a problem.
  • When you use GTD you know that you're putting your efforts in the places you want your efforts to be. You're only ever bothering to do the stuff that leads you towards your goal.

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