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38 SMT007 MAGAZINE I AUGUST 2019 molecular growth, there are no voids or air bubbles to pose a catastrophic risk upon rapid pressure changes. Biocompatibility and Biostability Neurostimulators, pacemakers, cochlear and ocular implants, electrosurgical tools, and an ever-increasing array of other devices can make a dramatic difference in patients' lives, provided they are biocompatible, biosta - ble, and can operate reliably when in contact with or implanted within the human body. Parylenes protect medical electronic compo- nents from moisture, biofluids, and biogases that can cause assemblies to fail prematurely. Such protection not only extends the life of the device but also reduces the risk of fail - ure at the most critical times. SCS Parylenes N, C, and Parylene HT comply with biolog- ical testing requirements for ISO-10993; test- ing included cytotoxicity, sensitization, intra- cutaneous reactivity, acute systemic toxicity, implantation (2, 12, and 26 weeks), hemo- compatibility (hemolysis and PTT), and pyro- genicity. The coatings are also certified to com- ply with the biological testing requirements for USP Class VI Plastics. Conclusion When choosing materials and solutions, product design engineers need to know both a product's function and how it will react in a given environment. To help ensure these requirements are met, industries outline various regulations that manufacturers— and often their subcontractors—must meet. These requirements establish standards against which products and processes can be tested and certified. While Parylene coatings can be evaluated based on their certification to various standards and industry regulations, coating suppliers can also be evaluated, in part, based on their pro- cess certifications and compliance. Following are a just few of the process and product spec- ifications and/or certifications that should be reviewed, if applicable, by manufacturers: • AS9100 and/or ISO 9001 management systems • Requirements of IPC-CC-830 • QPL for MIL-I-46058C • Production Parts Approval Processes (PPAP) • European Union's RoHS Directive • REACH compliance • Halogen-free initiatives • ISO 10993, USP Class VI biological evaluations and certifications • ISO 14644 cleanrooms • UL (QMJU2) As worldwide industry requirements and directives continue to evolve, manufacturers must ensure their products comply with rel- evant standards. Additionally, they must be certain that their products operate reliably in whatever conditions they encounter. Parylene conformal coatings provide designers and engi- neers a range of solutions to help increase the reliability and performance of their latest inno- vations. SMT007 Tim Seifert is an aerospace and defense market manager at Specialty Coating Systems. Parylene (top) vs. liquid (bottom) coating comparison.