COATING TECHNOLOGY
SECTION TITLE
chemicals, and ASTM’s B117 Salt Corrosion test of 750 hours. By varying the coating colour from clear to opaque in a variety of tints, the coating can also be made to look like brass, copper, brushed nickel or antique bronze, says Chin.
As an example, he explains how to
achieve a brass finish. “A brushed tinplate has a fairly bright finish, so applying a thin transparent gold or brass coloured coating over the tinplate enables you to pick up the brightness of the tinplate and get the right colour that simulates a natural brass-plated or brushed brass product.”
Whether simulating stainless steel, brass, or another high-end metal, however, the process usually saves the OEM and consumer a significant sum, while offering a high quality looking product. “Te simulated stainless steel and other simulated coatings are often less expensive than the comparable laminate,” says Chin. “Tat’s because laminates are usually in the 4 to 8mm range in thickness, while the coatings are well under 1mm. So the material cost would be less. Since it is applied efficiently in a
high-speed coil coating process, it is also less expensive to apply the coating than a laminate, whether on a coil-line or in- house.” Because the simulated metal coatings with their accompanying substrates are formable, and can be made ductile enough to even withstand deep draw forming, they can conform to virtually any appliance or product configuration.
When used with appliances, the simulated stainless steel coatings maintain the ability to magnetically hold artwork, so in both appearance and function retain much of the charm of the premium metal, but at a considerably lower cost. One caveat for OEMs and manufacturers looking to explore using these high-performance coatings to simulate premium metal finishes: it takes expertise to get it right, so work with an experienced partner. As an example, Chin points to the use of tinplate, which is one of the most popular metals used with this process due to its inherent brightness and reasonable cost. “Although tinplate is a popular substrate, it is not easy to adhere to it,” says Chin. “You have to specifically formulate
the coating for the tinplate application or you can have all kinds of problems with adhesion. Tere are limitations on process temperatures because the tinplating reflows at temperatures above 410°F.” For cases where the cost of tinplate would also add to the cost, for the simulated stainless look, standard cold rolled steel can be used since the coating system covers the metal surface.
PROTECTING THE BOTTOM LINE Some managers at OEMs and manufacturers may be inclined to use stainless steel laminates or brass and copper coated products because of their familiarity with such processes. However, those who take advantage of the outstanding capabilities of high- performance simulated stainless steel or premium metal coatings will provide a much larger segment of consumers with top-notch aesthetics and function at a much more affordable price.
Del Williams is a technical journalist based in Torrance, California, USA
Surface Technologies
l Controlled Shot Peening l Laser Shock Peening l Thermal Spray Coatings l Dry Film Lubricants l Organic and Inorganic Coatings l Parylene Ultra-thin Conformal Coatings l Superfinishing l On-site Processing l Material Testing and Analysis
l NADCAP, ISO 9001:2008, ISO 13485, AS9100 Rev C
For more information and full worldwide contact details:
www.cwst.co.uk or contact 01635 279621
www.engineerlive.com 59
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