Specification Story

["Mike Woolbert" <mawoolb@charter.net>]

I recently worked at a large petrochemical plant.  One of the highest =
volume products was ethylene, a light gas that was sold to other plants =
that made polyethylene plastic.  Polyethylene production process just =
hooks the little ethylene molecules together in a long chain with the =
aid of a process catalyst.  The catalyst used to make the polyethylene =
process work has become more and more complex and therefore sensitive =
ethylene impurities.  These impurities cause the polyethylene to not =
perform in certain specialized applications. =20

For years we produced ethylene to specification.  Each year the =
customers would negotiate for "tighter" specs so that their newest =
catalyst could make the latest plastic variant.  Finally, the customers =
demands exceeded our capability.  We rebelled.  We told the customers on =
our pipeline system that we produced the purest ethylene they could buy =
and their specs were beginning to violate natural laws.  Reducing one =
impurity would increase the volume of another.  We asked if they really =
knew what they wanted.  As it turn out, they really didn't know what =
effected their catalyst and were just guessing that reducing one =
impurity or another might help. =20

Finally, we resolved the problem by eliminating specs.  The polyethylene =
producers agreed to tell us when their catalyst was working properly and =
we would note our processing parameters that produced the "good" =
ethylene.  Our focus became running the process in a manner that =
produced the ethylene quality they needed. We worked to reduce variation =
in the process, not the product.  The output was right, because we made =
it the right way.  The customer got what they wanted and we were able to =
become the preferred supplier.  Luckily for us, we had started =
calculating process capability and had applied many Deming principles, =
so this solution was obvious and easy to apply.  I think this is one of =
the few times controlling process variation was a natural consequence of =
meeting the customers needs.

Mike Woolbert
Improvement Systems Consulting
mawoolb@charter.net