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Good Morning - comments to your questions:
2. Has anyone developed workmanship standards more specific to
intrusive reflow soldering than those listed in IPC-A-610?
**Take a look at IPC JSTD 001 for possible help
3. Most of the components we are planning to use this process on have
the leads placed such that it will be difficult or impossible to
inspect the solder joint from the screenprinted side of the board,
which is where we are hoping to get the good solder fillet. From a
practical inspection standpoint, the only thing it looks like we can
tell our touch-up operators is that the solder joint should be
considered OK if there's solder visible in the hole when inspected
from the opposite side of the board. This has us feeling a little
uncomfortable
... how are other people handling this?
**Hidden solder joints can't be inspected visually and therefore you
have two choices: 1) Pray that the process gods are generous and let
your process run perfect; 2) Conduct process control and run the
process in a proactive mode. I wouldn't bet on #1! I suggest that you
focus on the printing operation as a control of the resulting reflowed
fillet geometry. The use of xray, Cyberoptics, and/or a destructive
coupon test are some methods for setting up and monitoring your
process to insure that continuous control is achieved. Bill Barthel at
Plexus has a bunch of experience in paste in hole and you might try
contacting him for lessons learned (see SMI 94 Proceedings, page 363
for a good paper on the topic of paste in hole by Bill Barthel).
4. Since the solder joints will be difficult to inspect, it becomes
ever more
important that we control this process up-front. What are the key
parameters
**Focus on your solder paste stencil operation and fine tune those
deposition parameters.
Good luck!
Dave Hillman
Rockwell Collins
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Subject: ASSY:Workmanship Standards For Intrusive Reflow
Author: [log in to unmask] at ccmgw1
Date: 6/11/96 5:01 PM
Some colleagues have a series of questions about intrusive soldering
(paste in hole). Any responses would be greatly appreciated.
1. Regarding workmanship standards for intrusive reflow, We are planning
on using IPC (IPC-A-610) workmanship standards, but call the screenprinted
side the "secondary side".
We would appreciate any comments!
2. Has anyone developed workmanship standards more specific to intrusive
reflow soldering than those listed in IPC-A-610?
3. Most of the components we are planning to use this process on have the
leads placed such that it will be difficult or impossible to inspect the
solder joint from the screenprinted side of the board, which is where we
are hoping to get the good solder fillet. From a practical inspection
standpoint, the only thing it looks like we can tell our touch-up
operators is that the solder joint should be considered OK if there's
solder visible in the hole when inspected from the opposite side of the
board. This has us feeling a little uncomfortable
... how are other people handling this?
4. Since the solder joints will be difficult to inspect, it becomes ever
more
important that we control this process up-front. What are the key
parameters
that others have found, specific to intrusive reflow soldering?
Thanks in advance
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