Page 102 - How To Implement Lean Manufacturing

The Significance of Lead T ime 81

production. They considered it waste. However, a quick review of some related operat-
ing practices showed the following.
First, in an attempt to find quality problems early, they had instituted a practice of
doing 100 percent inspection of the first production piece from the punch press. This
was done using an automatic optical inspection tool. In addition, it was their policy to
stop producing after the first sheet until the quality tech gave them first-piece approval.
This inspection process step was to take 12 minutes. However, the inspection was often
a holdup and took far longer than 12 minutes. I reviewed some records and found that
over the last two months, the inspection delay averaged 46 minutes (above the 12-minute
inspection time allocation). Everyone was aware of this, and no one liked it, but the
bottom line was there was no action or even a proposal to reduce it. They simply
accepted this time delay but would baulk at the time delay caused by another setup.
Second and even more pointedly, the CNC punch press was only scheduled to run
73 percent of the time, maintenance included, and it was staffed 100 percent of the time.
So they were paying the same for it whether it was running or not. In this case, at this
time, changeovers were free on this machine, yet they baulked at doing them.
So it is easy to “see” that they have some serious wastes in the system that are larger
than the cost of a changeover, yet these go “unseen.” This is not unusual and we find
this in many businesses. Often, it is due to the paradigms these businesses live with,
and these paradigms typically go unchallenged. The paradigm is not the problem—we
will always have paradigms. The problem is the unwillingness to challenge the status
quo. Herein lies the advantage of having a consultant (or sensei) to assist you. He/she
will “see” these opportunities much quicker than the people within the business will
see them. Consequently, your consultant will bring forth opportunities that you might
be blind to. Your consultant will help you in your “Learning to See.” This is invaluable
help and the following paragraphs will describe how that advantage was turned into
solving business problems and, in a phrase, making some money.
Lead Times Are Dramatically Reduced
Table 5-2 shows the key Lean metrics of first piece lead time and batch lead time.
First piece lead time, a key measure of responsiveness, is cut by 75 percent, and total
time to deliver the completed lot is cut in half. All of this was achieved by simply:
• Reducing the batch size
• Applying SMED
• Balancing the assembly cell
• Implementing a type of jidoka
We were able to do it faster, better, and cheaper. And the most encouraging lesson
from this story is, we are just getting started!!

First Piece Lead Time Total Lead Time
Large lot, 100 units 620 minutes 1220 minutes
Smaller lot, 20 units 140 minutes 630 minutes

TABLE 5-2 Lead Time Changes, Bravo Line