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moldmakingtechnology.com 21 Depositing DLCs There are multiple commercially viable methods for depositing these films, all of which use a vacuum chamber setup. With this approach, molds and mold components are thoroughly cleaned prior to loading into a chamber to remove oils, scaling, oxidation and other surface contaminants. They are then load- ed into the deposition system, which is pumped to a very low pressure (1×10-6 Torr or less). After additional surface clean- ing (etching) in the chamber, the coatings are built through the bombardment of carbon atoms and other elements at a high enough ion energy level to create chemical bonding between the introduced atoms and the surface, as well as to each other. While a small amount of methane is a byproduct of deposition, the actual coat- ing is inert and not an environmental hazard. Through either a wet chemistry process or plasma etching, DLC coatings can be completely removed and then recoated; modified through machining or welding, and recoated; or chemically etched and recoated, as required. Every DLC coating consists of an amorphous (non-crystalline) mixture of diamond and graphitic-phased carbon. A nanocomposite coating was applied to this tool steel mold. This allows users to achieve much higher shot counts before mold maintenance is required. When coating wear appears, the mold can be stripped, repolished and recoated with, in most cases, a negligible amount of mold material loss. The inclusion of elemental dopants in many of these recipes can help control film stress, provide reduced surface energy, enhance wear characteristics or create an advantageous tai- lored characteristic. The elemental dopants are non-carbon additives introduced at very low levels to produce specific material characteristics. For example, adding a metal dopant to enhance oleophilic (affinity for oil) behavior. In the case of aluminum, carbides are not natively formed on the surface, so carbon ion implantation is required to estab- lish anchor points for the coating. Based on this approach, there are many DLC recipes for producing the desired coating morphology (the microstructure of the metal surface) and tri- bological (friction, wear, lubrication and interface parameters of a material) performance parameters. This well-balanced combination of properties allows DLC coatings to increase mold life, eliminate part sticking and reduce cycle time. FOR MORE INFORMATION United Protective Technologies (UPT) 877-552-8744 mefird@upt-usa.com upt-usa.com CONTRIBUTOR Brent Barbee is chief technology officer and managing member and Dave Duff is senior account executive with United Protective Technologies (UPT). Tooling Technology HAIMER Power Series Shrink fit precision and rigidity –The best on the planet. 40 Years Quality Measuring and Presetting Technology www.haimer-usa.com Balancing Technology Shrinking Technology