Quality 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 the
use 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 the user.
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.
Powder Coaters Manual
June 15, 2012