Appliance Design - September 2008 - (Page 46) DECORATION of the metalized layer, prevents out gassing from the base plastic, and smoothes the surface, adds Hatkevich. The magnetron sputtering process in use is a cool to warm processing system. Under most circumstances the part temperature does not exceed 100 DegF, and rarely rises above 150 DegF. Thus, most substrates can be processed. With sputtering, atoms are dislodged from the surface of a material as a result of a collision with high-energy particles. The atoms then condense on the substrate as a thin film. After receiving the smoothing base coat, the part, or batch of parts, is placed into the sputtering vacuum chamber. The chamber is then drawn down to a vacuum. For instance, American Trim uses a vacuum pressure of around 5.0 x 10 -5 Torr. The chamber is then flooded with argon gas, and the magnetron is energized. The magnetron applies a negative voltage, about -300 V, to the target, which is the chrome material that will be applied to the substrate. This negative voltage attracts the positive argon ions to the target surface, bombarding the surface and ejecting the chrome mate- Physical Vapor Deposition Powder Coat Wash / Pre-Treat Top Coat Vacuum Vacuum Purge Vacuum Purge Vacuum Sputter Cure Cure Cure 1 Part Every 2 Minutes 10–15 Minutes – Estimated Traditional Chrome Degrease Grit Blast Chrome Alkaline Grind / Polish Nickel Rinse Rinse Rinse Rinse Rinse 1 Part Every 12 Minutes Etch 3 – 4 Hours Estimated 45 Minutes – Estimated A comparison between the steps used in American Trim’s PVD process vs. typical electroplating process. rial atom by atom. A “plasma” gas is created, sometimes called a “glow discharge,” made up of electrons and chrome and gas ions in a high energy state. (The glow is caused by the ions relaxing to a lower energy state and emitting energy in the form of light.) The atoms released from the target are attracted to the lower energy substrate and condense on its surface atom by atom until the desired thick- ness level is achieved. The magnetron also establishes magnetic fields that trap secondary electrons that were ejected from the target and keep them near the target to enhance ionization and generate a higher density of ions. With a higher density, deposition rates improve as the gaseous cloud condenses on the substrate. This process is continued for each layer Fluorex bright film comes in roll form. Soliant 46 applianceDESIGN AD09081Zett.indd 1 September 2008 8/11/08 11:44:03 AM www.applianceDESIGN.com Seal http://www.zettlercontrols.com http://www.zettlercontrols.com http://www.appliancedesign.com
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