Due to the application methods of hard coatings on plastic substrates, blemishes do occur. These blemishes take the form of coating inclusions, trapped fibres and exaggerated material defects. So that SEM can work with these products, it is important to lay down a specification and inspection criteria. This is a specification which we feel is obtainable and repeatable, when viewed against past performance of coating suppliers. With individual project discussions, it may be possible to tighten up the specification, but this will be done by inspecting out defects and will have obvious implications on price.
Inspection Conditions.
The panel should be viewed from the front face under daylight conditions, with normal non-directional lighting. Viewing should take 15 seconds and from a distance of 450 mm.
Blemishes.