During thermal cycling, two or more of the dissimilar materials often found in today’s cars, such as a plastic and a metal, can produce noise when they touch each other, Hagemeyer says. Anti-friction coatings can reduce the amount of noise and vibration in an assembly or an engine -- something increasingly important in today’s small engines and cabins, where less noise is being masked from passengers.
Dolan said Henkel’s EC2 coating can improve emissions in automotive engines. By replacing the piston skirt coating, it increases overall engine efficiency by 2 percent to 8 percent, since the piston skirt is responsible for about half of engine friction.
Engineer it right the first time
Plastics are increasingly used in many machines, and their coating requirements are quite different from those of metals. “The biggest threat to many resins isn’t corrosion, but scratching or damage from ultraviolet light,” said Bill Welch, vice president of engineering and CTO for Phillips Plastics. Though many plastics are UV-stable, others, such as polycarbonate, require hard coating to prevent scratching and UV degradation.
Welch said one approach to solving corrosion and other problems often addressed by applying a coating is to select the right material in the first place.
“Material selection is key, whether you’re talking about metals, plastic, silicone, or ceramics,” he said. “By selecting the right material for the job, you can sometimes find an engineering solution to avoid corrosion. For example, we have in many cases redesigned metal products to convert to plastics to solve corrosion issues.” By applying structural analysis with material selection, engineers may be able to choose a combination of molding process and material for designing a product without the need for coatings.
The key questions engineers should ask in materials selection are what problem you are trying to prevent, what is the best material to prevent that problem, and how you can engineer a low-risk solution, according to Welch.
“Incorporating these questions into the early product development phases can prevent issues that would not otherwise be found until later development phases,” he said. “The focus is on defining the environment in which the product must work, and on what failures you’re trying to prevent from happening in that environment.”