Would the same principle apply to conformal coating?
 ----------
From: Mike Barmuta
To: [log in to unmask]
Subject: Re: [TN] ASSEM: MATTE VS GLOSSY
Date: Thursday, June 04, 1998 1:15PM

        Robert: Matte soldermask has a higher surface energy than gloss
mask.
Because of this it wets more easily and holds a more uniform thicker coating
of flux than the gloss. You can use the analogy of a waxed car (low surface
energy)it does not wet and retain a coating of water, it beads up and runs
off,
same thing for the gloss mask.
        Since the matte mask holds more flux, wave solder settings like
preheat/conveyor speed have to adjusted (more preheat/slower speed)to drive
off
the volatiles in the heavier coating of flux before contacting the
solderwave.
Also flux applicator settings, especially spray type can be adjusted to
control
the amount of flux on the board.
        Glossy mask run at these same settings could dry out and create
solder
webbing or bridging when run thru the wave. Glossy mask also has a greater
tendency to form solder balls which may require additional adjustments of
the
the settings to minimize.
        With one standard mask your assembler will not have to do as much
process adjusting and will probably provide a more consistent product. My
guess
is they would prefer the matte.

                                        Regards
                                                Michael Barmuta
                                                Staff Engineer
                                                Fluke Corp.
                                                Everett Wa.
                                                425-356-6076

On Thu, 4 Jun 1998 05:22:57 -0700 Robert Welch wrote:

> From: Robert Welch <[log in to unmask]>
> Date: Thu, 4 Jun 1998 05:22:57 -0700
> Subject: [TN] ASSEM: MATTE VS GLOSSY
> To: [log in to unmask]
>
> Hello Technetters,
>
> I've been asked to forward this inquiry for a contract assembly
> person we deal with occasionally.
> His problem is that he has to adjust his wave solder parameters (more
> or less preheat??)  when changing between "very shiny" and "very
> dull" solder mask on the same part number.  He would like some
> collaboration of this phenomena to help  justify
> requiring his supplier to keep  all the mask the same.
>
> Thanks,
> Robert E. Welch
> Process Specialist
> Email: [log in to unmask]
> Modem: 804-239-9120
> Fax:   804-237-3048
>
> ################################################################
> TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
> ################################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with
following
text in the body:
> To subscribe:   SUBSCRIBE TechNet <your full name>
> To unsubscribe:   SIGNOFF TechNet
> ################################################################
> Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional
information.
> For technical support contact Hugo Scaramuzza at [log in to unmask] or
847-509-9700 ext.312
> ################################################################
>

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following
text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional
information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or
847-509-9700 ext.312
################################################################

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################