Page 83 - How To Implement Lean Manufacturing

64 Cha pte r F o u r

Process Simplification Process simplification is a basic concept, but is frequently over-
looked by most. It is the idea of eliminating and simplifying steps in the production
process. This is one of the most powerful variation reduction techniques you can
employ.
Sustaining the Gains Sustaining gains is the concept that once a process improvement
is achieved, the next step is to standardize it. Thus, we want to institutionalize the gains
so they will be there forever. We then want to build on this gain. It is curious that almost
everyone knows this, but almost no one does it, not even modestly. In my work with
over 200 companies, I can’t give you one example of any company that does this well.

Quantity Control

Strategy
The quantity control strategy has two “pillars”: jidoka and just in time (JIT).

Jidoka
Jidoka is a revolutionary 100 percent inspection technique, developed by Toyota. It is
done by machines not men, using such techniques as poka-yoke (error proofing), which
will prevent defects from advancing in the system by isolating bad materials and/or
implementing line shutdowns.
It is also a continuous improvement tool because as soon as a defect is found, imme-
diate problem solving is initiated, which is designed to find and remove the root cause
of the problem. In the design case, the line does not return to normal operation until it
has totally eliminated this defect-causing situation.
This powerful concept has been in place at Toyota since its inception as an auto-
maker. In the Toyoda family, it was first implemented in 1902 when it was applied to
looms to trigger shutdowns automatically when a thread snapped. Since then, jidoka
has been continually evolving to higher levels of sensitivity. It is truly a revolutionary
concept. (Read about the impact of jidoka in Chap. 15.)
A great deal has been written about jidoka in cultural terms, with such topics as the
interworkings of men and machines, which allow the machines to do the repetitive
simple checking and let men do the higher-value work, such as problem solving. Ohno
called it “autonomation,” and he speaks of it in terms of “respect for humanity.” Here
is also where the revolutionary concept of “shutting down the line by the operator for
production problems” is also manifest.

JIT
Just in time (JIT), on the other hand, is designed to deliver the right quantity to the right
place at precisely the right time.

Tactics, and Skills for Quantity Control

The Jidoka Pillar

Poka-yoke Poka-yoke is a series of techniques, limited only by the engineer’s imagina-
tion. The purpose of poka-yokes is to achieve error proofing of a process activity and