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February 2018

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Subject:
From:
Lee Hitchens <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Lee Hitchens <[log in to unmask]>
Date:
Thu, 8 Feb 2018 10:06:54 +0700
Content-Type:
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text/plain (70 lines)
A few solutions we have been offering are to

  * Pre-coat critical components in a hydrophobic coating before actual
    assembly
  * Pre-apply a hydrophobic coating around the connectors before
    application.
  * Apply the hydrophobic coating to masking boots

This gives the components or masking some ability to "reject" the 
conformal coating being applied due to the change in surface tension and 
certainly can reduce incidence of capillary. Contact me offline for more 
details.

Best Regards

Dr Lee Hitchens

Please be aware that I am personally based in Thailand and travel frequently due to business.

If I am unavailable you can also contact my offices directly in the UK, USA and India for support.

Mob: +66 95 418 5931
Skype: leehitchens

UK: +44 1226 249 019
India: +91 900 038 3674
USA: +1 206 257 9787

www.conformalcoating.co.uk

SCH Technologies is a Division of SCH Services Limited

On 08/02/2018 10:01, Richard Kraszewski wrote:
> Yup  Real common for  unsealed connectors.
>
> You either have to find a better masking solution (often not possible) and/ or use  multiple layers of a highly atomized  (dry ) spray that is not very mobile  when it hits  the PCBA.
>
> Some unsealed  ZIF connector styles where the requirement is coat the leads but contacts are all KOZ are really a problem  for me due to capillary action of the coating if still wet when it hits the PCBA.
>
>
>
> Rich  Kraszewski
> Senior Staff Process Engineer
> Plexus Engineering Solutions
> * * * * * * * * CONFIDENTIALITY NOTICE * * * * * * * *
>
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> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Jack Olson
> Sent: Wednesday, February 07, 2018 4:17 PM
> To: [log in to unmask]
> Subject: Re: [TN] IPC-CC-830 (Conformal Coat)
>
> sorry for the long delay (and thank you for the responses) but as I was reviewing these posts I had another question:
>
> Have you ever heard of problems with conformal coating material wicking up the connector leads and causing intermittent connections?
>
> thanks again,
> Jack
>
>
> On Wed, 6 Dec 2017 14:09:46 -0500, lduso - Diamond-MT.com <[log in to unmask]> wrote:
>
> (..snip...)
>> It's up to me to decide how close to J1 to get with the coating. I once
>> coated the leads of all the fine-pitch connectors and the customer said
>> that was too close. The next customer will reject the work if I don't
>> coat the leads.

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