LCC/LGA Module Series
Module Secondary SMT User Guide
Module_Secondary_SMT_User_Guide 22 / 25
5
Desoldering
Please use a heat gun to heat the solder joints so as to remove the module from the motherboard.
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The temperature of the heat gun should be about 350ºC in order to release enough heat. The wind
speed should be adjusted according to actual situation.
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If the motherboard has been exposed to the air for exceeding 72 hours, then it should be baked
before desoldering.
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During heating, the motherboard should be laid flat and fixed to avoid movement, and the distance
between the motherboard and the nozzle should be from 1.0cm to 3.5cm.
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Move the nozzle along the edge of the module at a constant speed. When all of the solder joints are
melted off, take off the module along the diagonal direction with tweezers. The time of the whole
process should be no more than 120 seconds.
For the module larger than 33.0mm×33.0mm, a BGA workbench or heat gun can be used to desolder
components. To prevent separation between pad and circuit as well as PCB blistering caused by
long-term heating on a single side, pre-heating is needed at the bottom side of the module when heat gun
is used for desoldering. It is recommended to inspect soldering quality of modules by X-rays.
Table 3: Heat Gun Desoldering Requirements
Parameters
Requirements
The maximum temperature
on the surface of PCB
260°C
Desoldering or soldering
time limit
40s-120s
Temperature measurement
and calibration
⚫
Use temperature measurement devices in calibration period to
measure the temperature (the heat gun temperature must be set
according to the actually soldering requirements).
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The temperature must not exceed 350°C.
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Temperature check point must be 5mm away from the nozzle of the
heat gun, and the nozzle must be placed vertically down when
measuring.
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Heat guns that cannot meet the temperature requirements are
prohibited to be used.
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Heat gun should be detected with grounding.
Nozzle shape and
dimensions
Select an appropriate nozzle according to the type of electronic
components.