Good Morning!
     
     Alloy Sn63 melts at 183C - that is the only 'given' in an equation to 
     make solder joints with that alloy! Your peak temperature that you 
     shoot for in a reflow operation is going to be a combination of the 
     printed wiring board thermal demands, the robustness of the types of 
     components you are using and the thermal characteristics of the flux 
     in your solder paste. I don't think that there is a "recommended" peak 
     temperature because of the wide range of variable inputs. An enormous 
     amount of time and equipment is devoted to giving a process engineer 
     tools to allow him/her to optimize an assembly reflow profile. I 
     usually shoot for 30 seconds at 194C but that is just my preference 
     and if I had to back it up with data I'd lose. Good Luck.
     
     
     Dave Hillman
     Rockwell Collins
     [log in to unmask]
     


______________________________ Reply Separator _________________________________
Subject: Peak Soldering Temp.
Author:  [log in to unmask] at ccmgw1
Date:    12/12/96 2:47 PM


Hi, 
     
I am fairly new to the PCB industry.  But when I read the book about the 
reflow soldering process, it takes normally 213C as the peak soldering temp 
when the melting point of the solder may be, say 183C.
     
My understanding is that, it takes sometime to melt and acheive a 
good solder joint.  But how to determine 213C?  Or put it this way, what 
is the minimum peak temp. one should maintain?  Have you come across any 
literatures that talk about it ?
     
Any input is appreciated.
     
Thanks.
Y.F. Wong
     
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