This document specifies the procedures for determining the dry-film thickness of an organic coating on a metallic substrate (coil coating).
Five appropriate methods are given in this document:
a) magnetic induction;
b) eddy current;
c) micrometer;
d) optical;
e) ruggedized optical interference.
The methods are applicable only to products with smooth and flat substrates, but the coating itself can be textured. In that case, for methods a) and b), the average of a series of readings will represent an average of the thickness of the organic coating, while method c) will give the maximum thickness, method d) can provide the minimum, maximum and average thickness, and e) will give the total thickness.
Non-destructive continuous-web methods on measurement of dry-film thickness are only applicable on method a).