Conformity Magazine - December 2008 - (Page 36)

Common Plateable Resins Acrylonitrile Butadiene Styrene (ABS) Polycarbonate (PC) PC/ABS Polyether Imide (PEI) Figure 1 shows selectively copper and nickel-plated enclosures for an EMI shielding application. Plating 2-Shot Molded Components Mold 2-shot plastic part, with one shot being a plateable resin and the other shot being a non-plateable resin. The plateable resin in the 2-shot molded part is typically catalyzed to include plating additive to promote the electroless copper plating deposition. The mold tool must be specially designed for the 2-shot molding process, and the both plastic resins must have compatible molding parameters. Peelable Plating Resist Selected or Custom Blended Plateable Grades Polyphenylene Oxide (PPO) Polypropylene Polystyrene Epoxy PEEK Urethane Graphite PPS Nylon Not Plateable Polyvinyl Chloride (PVC) Polyethylene Polybutylene Terephthalate (PBT) PC/Polyester Liquid Crystal Polymer Polyphthalamide (PPA) Peelable plating resist can be used to mask defined areas of a part and produce complex masking patterns that are not feasible or cost-effective with alternative processes. The plating resist is applied onto the required areas by dispensing or spraying, followed by UV cure. The part is subject to conventional electroless plating to apply initial copper plating. The resist is then peeled off the part. Subsequent electroless or electroplating can be used to finish the part to the final requirements. Table 2 summarizes each selective plating system. Conductive Paint Conductive paints are comprised of micron-sized metal particles of nickel, copper, silver plated copper or silver blended into water or a solvent-based paint system. Similar to selective plating process, a masking fixture is used to control the location of the conductive paint that is sprayed onto the required areas of the part. The fully cured conductive paint thickness ranges from 0.0005” (0.0125 mm) to 0.002” (0.05 mm), depending on the paint type and EMI shielding requirement. The paint can be applied in a manual paint booth, where an operator applies the paint with a paint gun, or with a paint Plating Precision Plating tolerance of +/-0.025” Comments Plating interior surfaces of enclosures for EMI shielding or grounding surface. Applications include connectors antennas, IC packaging and sensors Table 1: Common plateable resins Figure 1: Selectively copper and nickel-plated enclosures for EMI shielding Process Plating Catalyst Candidate Resins Plating Options Primarily ABS and PC/ABS Electroless plating only, and selected PC resins typically copper/nickel 2-shot Molding Catalyzed resin for plateable area. Nonplateable resin needs to be compatible in molding process to plateable resin Plateable resins, including ABS, PC/ABS, Polycarbonate, PEI, PPO, LCP, PPA, etc. Electroless followed by Electroplating if required. Available metals include copper, nickel, tin, gold and chrome Electroless followed by Electroplating if required. Available metals include copper, nickel, tin, gold and chrome Tolerance function of 2-shot molding capability. Can attain line width of <0.020” (0.5 mm) Subject to part design Peelable Plating Resist Suitable for complex part design where 2-shot or laser activation process is not feasible Table 2: Selective plating processes 3 Conformity DeCember 2008

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Conformity Magazine - December 2008 Contents Editor's Note FCC Warns Regulatory Fee Payers About Potential "Phishing" Commission Prowls the Web to Enforce Its Regulations First DTV Rollout Initiated in Wilmington, NC New Standards List Released for the EU's Directive on the Safety of Toys ESD Association Call for Papers ESDA. JEDEC Announce Standards Development Cooperation Commission Releases Data on Local Telephone Competition The Future of ESD Testing ESD Open Forum Emerging Issues in Standards: China RoHS: One Year and Counting Challenges in Testing: Revisiting 10-Meter and 3-Meter Radiated Emission Measurements Design Fundamentals: Meeting the Shielding Challenges of Injection-Molded Plastics Focus On...Microwave Absorbers Buyer's Guide FDA Recalls Automated External Defibrillators FDA Revises Guidance on Medical Device Tracking Guidance Document Safety of Passive Implants Released FDA Offers Guidance on Marketing Diagnostic Ultrasound Systems EU Commission Issues Correction on Machinery Directive Standards Other CPSC Actions in the News Product Reviews IEC Standards Update UL Standards Update Looking Back: Items from Past Issues of Conformity Advertisers

Conformity Magazine - December 2008

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