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22 JANUARY 2016 — pfonline.com PLATING Why We Are Opening a Shop in Mexico By Mark Burger, KC Jones The automotive industry in Mexico has grown rapidly over the last 20 years, increasing its North American production share by 12 percent, while the United States' decreased by 11 percent. Today, Mexico is the No. 1 exporter of automotive parts to the U.S., the largest manufacturer of vehicles in Latin America and the seventh largest manufacturer of vehicles worldwide. Additionally, it is the sixth largest exporter of automotive parts worldwide. In 2014, Mexico produced over 3.3 million vehicles. It is expected to produce more than 5 million by 2020. This rapid growth created urgent needs for quality suppliers with their bases in Mexico. part or the deposit has, the more likely it is that those parts will become more anodic (more prone to corrosion) to their less- stressed counterparts. Designing Parts Another factor to keep in mind is that part design has a lot to do with the ability of a part to be corrosion resistant, as do the substrate itself, the type of lubricants used, the finishing and manufacturing methods, and the overall geometric complexity of the piece. Simpler parts have a smaller or tighter range of current densities (few extreme high and low regions) and thus are able to be plated with more thickness uniformity and are thus more corrosion resistant. Parts that have deep recesses or more areas of low current density will tend to perform worse than parts that do not have recesses or crevices. Plating in these areas will be thinner, so the ability of a corrosive particle to penetrate to the base metal is greater. If you cannot adjust the way the part is manufactured entirely, you may be able to convince the fabricators to fix a few elements that would positively affect deposit uniformity. Gently curving, convex surfaces are preferred over ones that have grooves, serra- tions, holes, concavities, fins, ribs, edges, valleys and recesses. Sharp angles and edges should be rounded off, softened, cham- fered or beveled. Slightly convex shapes are actually preferred to flat areas. Grooves cut into a metal part should be rounded into a shallow, U-shape versus a sharp, deep, V-shape. Try to avoid processing parts separately that will eventually need to be fitted together because the two parts together tend to form grooves that can produce a capillary that will soak up liquids during the plating process. If the manufacturer refuses to concede to making some alterations, you may have to chemi- cally process the parts in a solution that simply has higher covering and throwing power to ensure higher thicknesses. Packaging, Transporting When packaging parts to be chamber tested, it is important to make sure the parts and packaging elements are free of contaminants, that they carry a preservative like a desiccant, are wrapped and cushioned to prevent mechanical damage, are compartmentalized to mitigate and moderate shock and vibra- tion, and are not bulk packaged. Other items to avoid when packaging parts are: cardboard, paper, and rubber (because of their sulfur components), flexible PVC (chlorine leaching is a potential hazard), any metal (because of the potential for galvanic cell formation), wood (due to the potential for resin leaks), and Ziploc bags. Permitted materials include: corrosion-safe paper products, polyethylene, polypropylene, cellophane, Formica, Styrofoam, fiberglass, and hard PVC. The following information is not an exhaustive representa- tion of everything that is required of an operator to perform his or her duties in running a proper salt-spray chamber, but rather it is a collection of information often missed when operators or customers analyze a chamber and its operation. Results from a salt-spray chamber can be affected by many things. Before submitting parts to a salt-spray chamber facility, ensure that the standards it employs fulfill the basics of what is expected from ASTM B117. Sometimes the required number of collection vessels/funnels in the chamber is not followed. One funnel is to be positioned as close to the atomization nozzle as the nearest sample and as far away as the furthest sample. Verify the records your operator keeps on the salt solution's specific gravity with their collection rate. The collection rate itself has a high amount of variability, requiring between 1-2 milliliters per hour. Specimen are not allowed to touch the wall of the chamber as condensed salt solution will run down and flush the test specimen. Parts should not be shading one another from the spray or fog, nor should they be dripping onto each other. It would be prudent to ask that your chamber operator take a picture of the chamber with your part in it so that you can take note of your part's orientation, its proximity to other parts in the chamber, and any other details that seem abnormal or disconcerting to you. Keep in mind that corrosion areas should only be evaluated on the areas of the part that are at the correct angle, which is 15-30 degrees. A lot of customers will assume that every aspect of the part is under diagnosis, but this is not the case. For