Terry,

That sounds like what I've seen. When it is thin, you can hardly tell
that parylene is there, but as it gets thicker, it is readily apparent
and can become cloudy looking or have a 'matte finish.'

I haven't seen that much variation on one board, though. Parylene is
usually pretty consistent in thickness.

Ben

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Terry Quinn
Sent: Wednesday, May 30, 2007 8:46 AM
To: [log in to unmask]
Subject: [TN] Parylene coating

Does anyone in this group have experience with variations in the
appearance of parylene coating?  Our vendor is applying parylene on a
small PCB.  Most of the boards still exhibit the glossy finish of the
original board mask but we see some units that have a distinctly dull or
matte finish.  Sometimes it is limited to one end or even a corner of
the board.  The vendor reports that this reflects a slightly thicker
deposition of the parylene coating and is not a cause for concern.  Can
anyone confirm this, or are there other ideas that might explain this
condition?  Thanks for your help.

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 Please
visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for
additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------