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Date: | Mon, 16 Jun 2008 10:05:20 -0500 |
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Hi Natasha!
Most of the time, I just leave it up to my stencil vendor to create my
epoxy stencils for me when I have to use them. They do that from the
solder paste layer.
Personally, I try to avoid using epoxy whenever I can, I just do a
double-sided reflow if there is SMT components on both sides of the
board. If I need to wave the board and the volume justifies it, I'll get
a selective wave solder fixture made which will mask off the SMT on the
bottom of the board. If it's a low volume board, and depending on the
amount of PTH components there are, I'll just have the PTH
hand-soldered.
A few reasons I don't like using glue are:
- It's messy
- There always seems to be handling issues with the boards after the
parts are epoxied on.
- It can't be too good on SMT parts being immersed in a 500-degree wave
Steve
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Natasha Baker
Sent: Monday, June 16, 2008 8:25 AM
To: [log in to unmask]
Subject: [TN] Glue Mask Requirements
Hi All,
I have a question regarding the glue mask when designing PCBs.
I am ordering the IPC SM-817 which provides requirements for surface
mounting adhesives, but am unsure if it will provide requirements
specifically on dimensions for the glue mask. Are there concrete rules
for glue mask dimensions? Or, should the glue mask just follow the
component outline? Also, is it always necessary to use a glue mask, or
only when components are placed on both sides of the board?
Best Regards,
Natasha
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