[PCB_FORUM] Strange solder paste mask creation... how to??
- To: <icu-pcb-forum@xxxxxxxxxxxxx>
- Date: Wed, 17 Nov 2004 11:42:14 -0800
OK here is one for the group...
We work with some rather strange shaped parts in the RF world... things that
are built the way they are built, due to physics, not some IPC or JEDEC
suggested "standard" footprint. (you digital folks are lucky... )
These footprints often have large odd shaped center "slugs" in the middle of
the package that needs to be soldered for RF ground and heatsink reasons.
Rather than put an equal amount of solderpaste on the slug (in other words a
1:1 solderpaste "pad" equal to the component "pad") we have found that smaller
solder paste shapes work better... the part will then not "float" on the huge
center pad, which can cause the outer, smaller pads to not solder correctly.
Making smaller solder dots and stripes on the center "slugs" roughly the same
size as the other connection pads works best.
Well, the problem with this is defining what ends up as several "pads" for
pastemask verses one (odd shaped) "pad" for the slug.
It looks as though the best solution, at this point, is to put the paste mask
on a new subgroup layer: package geometry pastemask_top and
pastemask_bottom... this permits us to add any unusual hourglass shapes, dots
or stripes, or whatever as recommended by the manufacture as needed.
I am just wondering, are there any other better solutions?
Gene Carman
gcarman@xxxxxxxxxxxxxxx
-----------------------------------------------------------
To subscribe/unsubscribe:
Send a message to icu-pcb-forum-request@xxxxxxxxxxxxx
with a subject of subscribe or unsubscribe
To view the archives of this list please login at
//www.freelists.org. Our list name is icu-pcb-forum
or go to //www.freelists.org/archives/icu-pcb-forum/
Problems or Questions:
Send an email to icu-pcb-forum-admins@xxxxxxxxxxxxx
Want to post a job listing ? DON'T DO IT HERE!
Better yet, join our jobs listing forum.
SUBSCRIBE: icu-jobs-forum-subscribe@xxxxxxxxxx
POST: icu-jobs-forum@xxxxxxxxxx
-----------------------------------------------------------
Other related posts:
