10. Coatings: Surface Roughness from Substrate to Topcoat
Module 10 of the Surface Texture and Tribology Short Course
What you will learn
How paint finish texture is the product of the substrate and all finish layers
How paint appearance is affected by the spatial wavelengths of the surface texture
Surface parameters for defining appearance
Instruments for measuring paint finishes
A painted finish can make the difference between a product looking low-quality or luxe. The appearance of a painted finish is affected by many factors, including the surface texture, viscosity, materials, etc.
In this module we look at how surface texture affects paint appearance. The lectures follow a particular issue involving paint in the automotive industry: the finish on the front and rear doors appeared differently, despite the panels being painted at the same time and all materials meeting specification. By analyzing the spatial wavelengths of the painted surface texture, manufacturers learned that they needed to monitor more than just Ra (average roughness): they needed to control the various wavelength bands that affect appearance.
Through this module we look at the analysis process, the lessons that were learned, and the practices and measurement instruments that the industry developed to better predict paint appearance. We also look at the specifications that were developed to control spatial wavelength bands on the incoming steel in order to produce repeatable final finishes.
This is Module 10 of the Surface Texture and Tribology Short Course. The full course is available on udemy, or you can select the individual course modules of interest to you. Enter "surface roughness texture tribology" in the udemy search bar to browse the full course and modules.