TECHNET Archives

June 2011

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
"Thayer, Wayne - IIW" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Thayer, Wayne - IIW
Date:
Mon, 27 Jun 2011 07:32:00 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (1 lines)
Hi Andy-

If the coating is clear, lightly contaminate the surface with a fine inert powder.  Then use a high power (200X or more) optical microscope with a calibrated vertical access to look at both the contamination and the surface which was coated.  Typically, the depth of field on these microscopes is about +/-3 microns, so you can get a pretty high resolution for the measurement.

Wayne Thayer

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of andi1978
Sent: Monday, June 27, 2011 4:24 AM
To: [log in to unmask]
Subject: [TN] The best method to measure acrylic conformal coating thickness (dry film) over populated PCB.

Dear TechNet gurus ...

Our company is looking for equipment to verify the conformal coating thickness on fully populated PCB after the product is received from our subcontractor (measure on fully dry conformal coating).
Our assemblies are heavily populated so that standard tool (calliper or similar) are useless in this case.

We were considering to use eddie currents technique (measuring tool with 5mm tiny probe with 45 degree angle) but we are unclear on the measuring method use by this system.
Basically on their website http://www.conformalcoating.co.uk/Conformal-Coating-Thickness-Measurement-Systems.php they said: measurement is taken over the ferrous or non-ferrous material which in my opinion means the measurement is taken through the conformal coating + solder resist to the closest/first copper layer inside the PCB.

By using this tool and to correctly calculate the conformal coating thickness, we have to add the solder resist thickness (with tolerance) plus we must be sure that the ground plate/layer is located just underneath the solder mask/measuring point.
In our case (complex assembly) this condition will not be always be achievable (read: no ground plate in the measuring area), complex build.

Have you guys any idea what would be the best, accurate tool/technique to verify the acrylic coating thickness on populating product.
Please bear in mind our boards are FTI equipment and conformal coating parameter is critical from product functionality/reliability point of view.
And again, there are not much "real estate" and the sensor to measure the thickness must be small in diameter as possible.

Much appreciate your advise,
Andy

______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

This e-mail and any files transmitted with it may be proprietary and are intended solely for the use of the individual or entity to whom they are addressed. If you have received this e-mail in error please notify the sender.
Please note that any views or opinions presented in this e-mail are solely those of the author and do not necessarily represent those of ITT Corporation. The recipient should check this e-mail and any attachments for the presence of viruses. ITT accepts no liability for any damage caused by any virus transmitted by this e-mail.

______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________




---------------------------------------------------

Technet Mail List provided as a service by IPC using LISTSERV 16.0

To unsubscribe, send a message to [log in to unmask] with following text in

the BODY (NOT the subject field): SIGNOFF Technet

To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)

To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest

Search the archives of previous posts at: http://listserv.ipc.org/archives

For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815

-----------------------------------------------------


ATOM RSS1 RSS2