Hi Ken -
     
     Are you having a solderability problem (i.e. the component leads are 
     not wetting with solder adequately) or are you having a 
     soldering-ability problem (the interaction of the soldering process 
     and the amount of component lead protrusion is creating poor solder 
     joints)? I would recommend you investigate your component 
     solderability first as one way of reducing the number of variables you 
     need to check to determine the problem source. I know that several of 
     the military specifications required a lead clearance range of 0.020 - 
     0.060 inches but I don't know the reason for that range (it may have 
     had no data basis). I have seen where flush cutting of the component 
     leads resulting in nearly zero lead protrusion resulted in poor solder 
     joints because of the exposed component lead basis metal. Good luck.
     
     
     Dave Hillman
     Rockwell Collins
     [log in to unmask]


______________________________ Reply Separator _________________________________
Subject: Minimum lead clearance through a multi-layered board
Author:  [log in to unmask] at ccmgw1
Date:    4/3/97 10:26 AM


We are using a multi-layered board and the thickness of the board has posed a 
problem to a couple components on the board.  After insertion of the component, 
the leads have a very minimal distance that they go completely through the 
board and this is causing a solderablility problem.  I have been unable to find 
any specifications, standards, articles, etc. on the minimal lead clearance 
through a multi-layered board.  Does anyone know of such standards?
     
Best Regards,
Ken Kowalski, Sr. Engineer
Picker International, Inc.  X-ray Division
     
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