Application note: Coating process quality
The material thickness of transparent surfaces and layers is critical for both their fitting accuracy and function. Inspecting layer thickness along the production process by performing measurements and constantly maintaining the exact same level is indispensable if high quality and a low rejection rate are to be achieved. If your job involves performing an areal analysis of how thick a transparent sample is or in detecting surface defects, then Polytec’s TopMap series is perfect for you.
A major consideration for most coating processes is that the coating is applied at a controlled and defined thickness. Coating technologies include composite coatings, nano coatings and ultra-thin films, deposition (plasma and ion-based vacuum), epitaxial film growth, sputter technologies, dip, flow and spin coatings, spraying, painting and rolling, electroplating and electroless plating, and or surface modification.
Control layer thickness and the entire coating process
The scratch test is a popular adhesion test for thin, hard and well-adhering coatings such as TiC (titanium carbide) on steel or cemented carbide substrates. Coating thickness measurement of non-transparent materials can also be measured at the edge of a coating or by a step-height measurement of the scratch. Layer thicknesses from a few μm upwards can be detected on transparent coatings at any position.
A wide variety of surface defects in coating and metallizing can be measured, qualified and catalogued, including voids, streaks, chatter, droplets, spots, dimples, holes, scratches, coating disturbances, contaminants, orange peel, and visual texture appearance. Defects can be quickly visualized, measured and the information used to help identify its cause, so that process cures can be quickly implemented, optimized and then monitored to show the improvements in end coated surface quality control. Defects can be measured and qualified on a coating to help identify the cause.
As an example, Polytec’s surface measurement systems are used to check and maintain the thickness of cell phone displays during production.