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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______________________________ Reply Separator 
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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