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Reply To: | TechNet E-Mail Forum. |
Date: | Thu, 22 Feb 2001 14:21:45 -0500 |
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RE: [TN] AW: [TN] Temperatures for Rework operationI agree with these guys
suggesting that 600°F is a high temperature for rework if we mean 600°F
measured on the board in in the molten solder. But I think we are talking
set points of the hand tool. There are a lot of variables in the equation;
thermal offset between the point of measurement and the actual tip, thermal
mass of the tip relative to the work piece, heat transfer area . . . and as
stated earlier, flux type.
All things being equal 750°F as a set point may be high for some types of
equipment; Pace hand tools for example where the operator can set the tip
offset to compensate for known characteristics of the tips.
Hand soldering and touch-up is as much skill as science. A skillful operator
can achieve good solder joint characteristics with the correct tip in a APE
hand tool can get good results from set points as low as 500°F.
But 750°F may also be perfectly acceptable; Older Weller designs with
magnetic switches for example. I have never even seen a 500°F tip for those
Weller hand tools.
In a former life, I went down the path the initial poster is taking. I found
the 600° setting on our hand tools caused a lot of trouble. We ultimately
compromised at 700° as a maximum set point, and sometimes our operators
complained and used 750°F (which is what they had preferred until I butted
in).
Later, we added a new brand of hand tool to our production line and 600°F
was the best general purpose temperature, and our operators rarely needed to
use setpoints greater than 650°F.
The message here is Know Your Process, Know Your Equipment.
Golfers . . . How far does a three iron go? . . . one with a hickory
shaft?
Guy Ramsey
American Competitiveness Institute
Senior Lab Technician / Instructor
610 362-1200 ext. 107
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