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Parylene FAQ


  1. How thick of a coating do I need?

    This question is not easy to answer, as different applications can require different thicknesses. Our engineers will ask why you are considering parylene (for its moisture barrier, lubricity, or dielectric properties, for example), and can then make a suggestion for your specific application.

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  2. Can we keep parylene out of specific areas?

    Yes. VSI Parylene has developed novel processes for the selective parylene coating of parts. Typical processes involve masking a specific area on a part. After the entire part has been parylene-coated, the masked area is demasked and you are left with a parylene-free area.

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  3. How do you get parylene to stick?

    Cleaning and preparation of parts prior to coating is essential. This is not cleaning in its typical form. VSI also adds an adhesion promotion step to enhance the adhesion of parylene to the surface.

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  4. Which parylene is best for my application, Parylene C or Parylene N?

    Parylene C is the work-horse of the parylene industry. Parylene N is typically used to coat areas that C cannot. The throwing power of Parylene N is much greater than Parylene C, meaning N will travel to places that C cannot go. It also takes twice as long to do runs of Parylene N because the molecule is more active than the C molecule.

    Depending on the properties required, it can sometimes be difficult to determine whether to use Parylene N or Parylene C. See the following table for more information. Assistance from one of our experienced engineers is just a phone call or email away.

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  5. How clean does our part need to be?

    Parts need to be as clean as possible prior to coating – no clean fluxes, oils, or fingerprints. The cleaner the part, the better the results.

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  6. How long will it take to coat our part?

    Parylene is not a fast process. Turn-around times are typically five days at minimum, but 2 – 3 days is possible thanks to our supply chain management experience.

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  7. Can you provide special packaging after coating?

    Yes, we are happy to provide custom packaging and shipping services to our customers. We can return shipments in customer-supplied packaging or ship directly to the end customer, if requested.

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  8. Why is a batch quantity so important?

    The parylene coating process works best with a full chamber. If we can only fit 100 parts in a chamber, 101 is a problem. Shipping in batch quantities also speeds up the production process and provides lower per part pricing for the customer.

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  9. What surfaces will parylene NOT stick to?

    Parylene will adhere to almost anything when the surface is prepared properly. There are several additional steps we can also use to promote adhesion.

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  10. How do we determine the thickness after coating?

    After the coating process, we measure test strips that are placed throughout the coating chambers. We then certify that the thickness meets your application’s requirements.

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  11. How can we know if there is really parylene everywhere?

    Parylene goes everywhere and sticks to everything. Our custom-built machine vision inspection system, as well as 100% microscope visual inspection on every coated part, ensures that your parts are coated to specification.

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  12. Does the coating have a cure time?

    No. Parylene does not have a liquid phase and, therefore, it has no cure time.

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  13. Can you color the coating?

    No. Because parylene is a clear polymer, it cannot be colored without degrading the parylene layer.

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  14. I know I need parylene, but I’m not familiar enough with it to know HOW I need it. How can you help?

    We can help in every aspect of engineering your project. Our engineers are passionate about creating special solutions for our customers. Our experience in project management and lean manufacturing can take your application to the next level. Call us today at (866) 767-5633 or fill out a contact form to discuss your application with a VSI Parylene engineer today.

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  15. How much will it cost?

    To provide you a quote, please call us anytime toll-free at (866) 767-5633 or fill out a “get started” form here. Once we discuss your application and can better understand your needs, we can provide you with a quote for your project.

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  16. What are the electrical, mechanical, and thermal properties of parylene?

    For a complete list of specifications, see our Parylene Properties page. The specifications is also available as a downloadable PDF on the page.

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  17. Can you provide me with gas permeability information for parylene relative to nitrogen, oxygen, carbon dioxide, and hydrogen?

    Parylene’s gas permeability specifications can be found on our Parylene Properties page and as a downloadable PDF on the same page.

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  18. What are the common advantages to using parylene over other conformal coatings?

    To learn about the benefits of parylene, click here

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