is often defined by subjective judgment.
What is acceptable may vary from one
day to the next, one shift to the next,
one inspector to the next, etc. Quantitative
information is necessary to create and
administer a proper quality specification.
Specific numerical ranges for gloss
and color, the numbers and description
of any dirt speck that may be acceptable
or not acceptable, corrosion resistance,
hardness, etc. Anything that relates
directly to the appearance or function
of the part being coated.
The properties that the coating must
have are directly related to theuse
of the product in the field. Quality
is actually defined by the expectations
of the most demanding customer. The
performance and appearance requirements
are dependent on the acceptance of
A quality specification that meets
the customer's expectations can be
priced into the product. A quality
standard that exceeds the customer's
expectations will add cost to the
product, reducing profits.
A standard that is below the customer's
expectations may not sell at all.
A quality control method that is subjective
will result in inconsistent output,
added cost and customer dissatisfaction.
Accuracy is important.
Powder coaters need to recognize
the variables that affect the coating
process and learn how to manage them.
G. Edward Demings defined quality
as absence of variance. It is true
that if a coating line focuses on
the reduction of variables that cause
defects, they can achieve the highest
possible yield of acceptable product.