10. Coatings: Surface Roughness from Substrate to Topcoat
What you'll 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
- No prerequisites. This module is part of the Surface Texture and Tribology Short Course, so viewing the other modules is recommended.
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.
Who this course is for:
- Scientists, engineers, technicians and students in the fields of automotive, medical device, aerospace, materials, polymers, and others
In 1994, Dr. Cohen established Michigan Metrology to help engineers and scientists solve problems related to “Squeaks, leaks, friction, wear, appearance, adhesion and other issues,” using 3D Surface MicroTexture Measurement and Analysis.
Dr. Cohen is a past Chairman of the STLE-Detroit section and has been active with the ASME B46.1 committee on surface texture since 1988, having served as Chair from 2005-2011. Dr. Cohen is also a Subject Matter Expert for the ISO surface metrology activities.
Dr. Cohen has an undergraduate degree in Physics from the University of Michigan, Dearborn, and graduate degrees in Physics and Optical Sciences from the University of Arizona. Early in his career, Dr. Cohen worked with IBM on optical disk drive development. He later joined WYKO Corporation as Product Manger and later became Vice President, leading the development of 3D surface texture metrology instrumentation.
Dr. Cohen has developed this class over the past 20 years having presented the material at numerous client locations as part of his training and consulting activities. Typically once a year the class is offered to a general audience in the Livonia, MI area.