Page 94 - How To Implement Lean Manufacturing

The Significance of Lead T ime 75

Time Impacts 1st Piece Lead Time, Cell 1 Shipment Lead Time
Original case 232 min (3.9 h) 149 h (6.2 days)
After lean 6.5 min 28.4 h (1.2 days)
improvements

TABLE 5-1 Bravo Line, Lead-Time Improvements

which will run another 6.2 days, letting us ship it in 12.4 days. Now, any planner who
values his life will add some fat to that because, if you recall, this line did not always
run to schedule. So the planner will promise something like 15 days and probably will
not sleep well until the shipment leaves.
On the other hand, with the Leaned out process, he tells them it will take 2.4 days,
and since it runs on schedule more often than not, he not only tells them we will ship in
three days, but he confidently delivers that message. But life is not always that kind.
Problems can arise in the best of systems. In the short lead-time situation, if the current
production is delayed, thus holding up the request from the new customer, it is known
in one day, making some countermeasures possible. In the long lead-time case, it may
take a week for the problem to surface. This is yet another type of flexibility inherent in
a short lead-time production system; the ability to respond to abnormalities more
quickly.
Please return to Chap. 2 and the section entitled, What is Lean? Here you will get a
good dose of just what we mean when we say it is “emotionally much Leaner.” That
planner can proceed with confidence and, quite frankly, he will sleep better. Those
examples abound in a Lean facility.
Responsiveness and flexibility are the life blood of a typical job shop. For them,
these advantages can be achieved through the reduction of lead times. We have worked
with a number of job shops and taught them the benefits of lead-time reduction by
using Lean techniques even though the application of Lean techniques are not as
straightforward in that environment.

Excalibur Machine Shop, Lead-Time Reductions
A look at the Excalibur Machine Shop will give us some insight as to the applicability of
these principles to a job shop using batch type operations.
The Background
We were hired to train Excalibur in Lean principles. Although they knew little about the
TPS (Toyota Production System) or Lean principles, they thought it might help them
with some of their manufacturing problems. They described their problems as:

• Labor efficiency was only 56 percent compared to their goal of 80 percent
minimum. This was a comparison of bid hours for a job compared to actual
hours worked.
• They frequently had quality issues. No job went through without rework; most
jobs had two or three episodes of rework.