Lean for High Takt Times
By Andy Wagner:
Mark’s Note: After some of my adventures in blogging about lean in aerospace, I got a volunteer to add some perspectives from that industry. Thanks to Andy for joining up and I look forward to his contributions. Click on his name for his bio.
Mike Wroblewski at “Got Boondoggle?” had an interesting post the other day after touring the Boeing 777 assembly line in Seatle. While the line was well organized, lean on inventory, and built on wheels for flexibility, Mike’s blog highlighted a few “less lean” aspects of the operation. He talked about how the workplace “appeared calm” and that there didn’t seem to be clear standard work in the conventional sense. There were no signs of a quick response andon system. Then again, as he mentioned, with a 3-day takt time, how fast does the response need to be? As an engineer in the aerospace industry, where even a fast takt time is 12-hours or more, I think Mike’s commentary begs the question, what does lean look like for large-scale products built in small quantities?
I believe Lean is clearly relevant to these types of operations. Even small components in aerospace can cost tens of thousands of dollars, meaning that inventory costs are much greater and single-piece flow more meaningful. While quality is a competitive imperative in automotive, in aerospace, lives are on the line, not to mention the future of the company. Nonconforming hardware is too expensive to scrap, and repairs or concessions require analysis and evaluation by engineering, taking resources from product improvement and development projects.
With twelve hours of machining in a single operation, and one operator tending two or perhaps three machines, what does standard work look like? Is a calm pace unexpected? A lean shop would have the machinist performing TPM. He or she would have a routine schedule for chip clearing, rather than waiting for problems to occur. And there would likely be at least one setup during the day, but with some operations (Boeing’s 3-day takt for example), would see a mostly calm and inactive operations team.
There are many industries where takt times are even slower than aviation. Construction, shipbuilding, and many other industrial products come to mind. The Navy has aircraft carriers built once every four years. Submarines every two. How can you begin to monitor progress of work at that pace? Is it reasonable, or beneficial to dictate the footsteps of standard work done twice in a decade?
Clearly, slower industries have much more to learn about lean. Toyota has discovered and developed the majority of our lean toolset, but I don’t think we know the answer to many of these questions about higher-takt times. In this area Boeing has made the commitment, and might very well be leading the way.