Lean process cycle time

Mike,
Your calculation for takt are absolutely right taking an average demand is the wrong part. We take maybe a six month look ahead in orders that is the customer demand. Takt may change up to 8 times a year on some value streams.
In aerospace we had 9 different aircraft types one would be on a move rate of three a week some one a month each had an individual takt time based on the demand for that  product.
The cycle time of each key stage or process was then evaluated if it was greater than takt you had to in goldratt terms exploit the constraint. You would create a yamazumi or line balance chart to identify the constrained stages from seeing this you can do many things .
Identify Value and Non Value add. eliminate the waste to get below takt. Introduce shifts on some stages or create identical stages called rate tooling. So you never under or overproduce as you are asking because the speed of your line increases and decreases with customer demand by flexing tooling positions and manpower.
Usually you had the luxury of one value stream getting faster as another slows down moving your manpower onto different contracts.
Hope you get this
All The Best
John M

Progress in manufacturing is measured by the production of high quality goods. The unit of progress for Lean Startups is validated learning-a rigorous method for demonstrating progress when one is embedded in the soil of extreme uncertainty. Once entrepreneurs embrace validated learning, the development process can shrink substantially. When you focus on figuring the right thing to build-the thing customers want and will pay for-you need not spend months waiting for a product beta launch to change the company's direction. Instead, entrepreneurs can adapt their plans incrementally, inch by inch, minute by minute.

By creating burn-up lines based on the CFD, you can make rough predictions based on your WIP and Throughput. This allows you to estimate if you’re on track with your planned work and whether or not you can expect to finish the work in a set amount of time. Using a burn-up on a CFD is similar to how a  burn-down chart  functions in the Scrum methodology, while providing additional flexibility. (Tip: Burn-ups work best when applied to a short time period; projecting an average over a longer timeframe will produce tidy, but highly inaccurate forecasts.)

Thanks for clearing up a general misconception. I myself used the term incorrectly for a while, then realized the difference – as you put it so clearly – and now I make sure to stress the distinction so others will not have the same confusion I did. In manufacturing, it may be self-evident, but in a service industry without automated / regulated flow, the terms are similar enough that it’s easy to be confused if you don’t start with a good definition. Thanks for giving us that and a good example as well,
Sue K.

Lean process cycle time

lean process cycle time

Thanks for clearing up a general misconception. I myself used the term incorrectly for a while, then realized the difference – as you put it so clearly – and now I make sure to stress the distinction so others will not have the same confusion I did. In manufacturing, it may be self-evident, but in a service industry without automated / regulated flow, the terms are similar enough that it’s easy to be confused if you don’t start with a good definition. Thanks for giving us that and a good example as well,
Sue K.

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