In many cases it depends on the "surface energy", in very simple terms : How much does the surface of a component have a bond with adhesive, defect, potting compound, etc.
The measurement of the surface energy is carried out with "test inks". A liquid with a defined surface energy is applied to the substrate. Depending on the behavior of the liquid, the surface energy is determined by for example beading, wetting or spreading.
The test ink sets are manufactured and filled in-house. They are available in steps from 30 mN / m to 105 mN / m.