Actually it's a simple UV bump of the thermal cured LPI. Just add's more
'oooomph' to the solder mask.
You can't push the ink over the board at normal speed either, take it nice
and slow and double pushing helps too.
No UV ink is used.
What we learned is when these are done in separate cycles it eliminated any
problems (i.e. blowholes) at the assemblers.
We don't make a practice as it is time consuming but for the have a handful
of product types we do this for, it's work without adverse incidents.
Franklin
----- Original Message -----
From: Jeff Hempton <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, March 17, 2000 5:54 AM
Subject: [TN] To plug or not to plug
> Franklin,
> Thanks to everyone for your responses on this so far.
> Do I understand correctly that you use a standard LPI and totally
> cover, or "tent" over the vias, then UV cure, then repeat on other
> side? And the UV cure keeps the LPI from creating a blow-hole during
> assembly? Or are you UV curing a separate "plug" material, then LPI
> covering?
> Jeff Hempton
> UT Electronic Controls
>
>
> ______________________________ Forward Header
__________________________________
> Subject: [TN] To plug or not to plug
> Author: Franklin Asbell <[log in to unmask]> at Internet
> Date: 03/17/2000 7:22 AM
>
>
> One solution we found to the LPI plugging issue is:
>
> STEP 1: Coat, tack, image, cure, then follow up with a UV cure one one
side.
> STEP 2: Repeat step 1 for the opposite side
>
> Yes, this is somewhat time consuming; however, it has worked out great in
the
> few exceptional jobs we needed to do this on.
>
> I welcome all other reasonable solutions.
>
> Thanks,
>
> Franklin D Asbell
>
----------------------------------------------------------------------------
----
> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
> <HTML><HEAD>
> <META content="text/html; charset=iso-8859-1" http-equiv=Content-Type>
> <META content="MSHTML 5.00.2614.3500" name=GENERATOR>
> <STYLE></STYLE>
> </HEAD>
> <BODY bgColor=#ffffff>
> <DIV><FONT face=Arial size=2>One solution we found to the LPI plugging
issue
> is:</FONT></DIV>
> <DIV> </DIV>
> <DIV><FONT face=Arial size=2>STEP 1: Coat, tack, image, cure, then
follow
> up with a UV cure one one side.</FONT></DIV>
> <DIV><FONT face=Arial size=2>STEP 2: Repeat step 1 for the opposite
> side</FONT></DIV>
> <DIV> </DIV>
> <DIV><FONT face=Arial size=2>Yes, this is somewhat time consuming;
however, it
> has worked out great in the few exceptional jobs we needed to do this
> on.</FONT></DIV>
> <DIV> </DIV>
> <DIV><FONT face=Arial size=2>I welcome all other reasonable
> solutions.</FONT></DIV>
> <DIV> </DIV>
> <DIV><FONT face=Arial size=2>Thanks,</FONT></DIV>
> <DIV> </DIV>
> <DIV><FONT face=Arial size=2>Franklin D Asbell</FONT></DIV></BODY></HTML>
>
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