Page 249 - How To Implement Lean Manufacturing

The Story of the Bravo Line 227

• Their concerns about quality were focused on the product only. They had a very
low interest in, and understanding of, process capability and process stability.
• Management never once mentioned that rework was a concern. They literally
had to be blind not to see it. It was a culturally acceptable norm to overlook
rework. Once we started the process, and observed its operation, the defects
stood out. Our jidoka concept made it procedurally unacceptable to proceed
without fixing the problems.
• Their view of downtime was odd, to say the least. They did not consider the
line to be out of service while all this rework was going on, even though they
were able to produce precisely nothing. That was “just how we do things around
here,” they said.

And the list could go on. At this point, we “began to see” that the required rework
both extended the time to produce a batch and also consumed much more labor than
was designed.
Production Improves Even Further
With these problems behind us, the line speed picked up and right before the shift
change we increased the conveyor speed so there were only two pieces between sta-
tions. Production went along without a hitch. After about 16 hours, we completed the
first batch of 1000 units in front of Cell 2. There was already a queue of 46 hours in front
of Cell 2. The next day, we returned and were able to break into Cell 2’s production
schedule, which had operated flawlessly with only three people. When our model got
there, it went through without event. In the ensuing days, we were able to work off the
materials in the Cell 2 queue and get it more in balance with Cell 1. After one week, we
had the flows essentially balanced with a small buffer (two–ten hours) in front of Cell 2.
We again tried to push the concept of a heijunka board. Had we done that, we felt we
could have effectively eliminated the queue in front of Cell 2. They again decided not to
change and continued to plan the two cells independently.
At this time, something very interesting, although not uncommon, happened. By
the end of the first week, the whole line production had sped up—some work stations
were under 30 seconds, and it looked like we could rebalance and thus need only five
people in Cell 1 and only two in Cell 2. No one could really explain it, but this phenom-
enon is known as the “Hawthorne Effect” (see the explanation in Chap. 14). After a
week, the line was producing smoothly, making over 2000 units per day and meeting
the model mix. Furthermore, they were doing it with less people, less space, and most
importantly, with less chaos.

The Results
Let’s now look at the impact of our efforts on the performance of the line. We will
review several aspects including:

• The impact on lead time, which was our original intent
• Other typical gains achieved in a lean initiative
• How the gains were achieved
• What should be next for the Bravo Line improvements