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II-6 Thermocouple mounting examples
Example 1) Measuring solder temperature
(When checking whether the solder temperature is high enough to fully melt the solder on a side face
of a larger part where temperature is hard to rise, or when checking whether the solder temperature
and heating time are enough to oxidize the inner part of solder at an end portion of a board)
1. Fix the thermocouple tip measuring part with flux for stainless steel and high temperature solder.
If solder is hard to attach, lightly sand the thermocouple tip with sand paper.
Note: Do not pile up the high temperature solder and make a large mound. The solder profile must
be akin to the actual shape of the part as far as possible.
If solder is oxidized, or if the oxidant of flux cannot be taken off from the surface, remove the
solder once, and then try again soldering.
2. Lay the thermocouple wire close to the board surface as far as possible, and fix with heat-resistant
tape at a portion slightly apart from the tip in such a manner as to avoid application of stress.
Note: When fixing with high temperature solder, be sure to use a solder whose melting point is
higher than the reflow oven set temperature.
Example 2) Measuring the temperature of a part
(This is to check whether the heat-resistant temperature, time and temperature shock of a part are
within the allowable range.)
1. Fix the measuring part of thermocouple tip by thermosetting adhesive or inorganic adhesive.
Note: Pay attention not to alter the outer shape of the part largely by adhesive. To obtain accurate
measurement, file a part of thermocouple tip and embed it into the part.
High temperature solder
Thermocouple
Board
Thermocouple
Adhesive