What is the solder mix - 60/40, 63/37?


______________________________ Reply Separator _________________________________
Subject: RE:ASSY: 
Author:  [log in to unmask] at internet-mail
Date:    5/14/96 9:36 AM


Dear Technet,
          
Whenever, I'm running a 100% through-hole board, that is densely populated 
with mainly DIP components, and a only few capacitors and resistors., 20 to 
30% of the solder joints are gritty. 
          
It had never happened to board of mixed technology.
I have sent the solder for lab. analysis, and the result is within the 
recommended specification.
          
The Board is :-
10 x 10 sq.inch
4 layers 
          
The wave-solder Machine used :-
The wave-solder machine used is SEHO 2000 - a full-blown nitrogenous tunnel. 
The solder pot temperature is set at 245 deg.cel or 473 deg.F.
The top side temperature is measured at about 194 deg.F / 90 deg.C. 
Conveyor speed is set 0.90 metre/minute.
The solid content of the flux is 1%.
          
Could anybody advise me why this is happening, and how to solve it. Our 
rework operators are touching every gritty joint.
          
          
Poh Kong Hui
Nera Electronics