Dinghua DH-5830, Руководство пользователя

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7
7、
Place the BGA chip
Place the BGA chip on the PCB board with manual alignment and silk-screen borders, meanwhile
the tension of the solder joint when melt will have a good self- alignment effect.
8、
Welding
First, put the PCB board which is pasted with BGA chip on the positioning stand, and then move
the hot wind head to the working place. Second, choose the appropriate backflow nozzle and set
right welding temperature curve, start heating, open the switch, and then run the welding process.
Besides, after the welding process is finished, you have to cool the BGA by the cooling fan. Hoist
the upper hot wind head and make the bottom of hot wind nozzle apart from the surface of BGA
3-5mm, and stay 30-40 seconds, or, you can move the hot wind head after the starting switch is
put out, withdraw the hot wind head.Finally, take away the PCB board from the heating zones.
(1)
null welding
：
Because of counterpoint by hand will cause deviation between chip and welding plate, surface
tension of tin ball will make BGA chip and welding plate in the process of automatic correction.
Once heating, BGA falls not evenly, which cause the chip drops not evenly.If stop reflowing at
this time, the chip will not fall normally,which will cause th phenomenon of empty welding and
false welding.So you need to extent time of third
、
forth temperature zones or add the bottom
pre-heating temperature to make ,the tin balls meltdown and drop evenly.
(2)
short circuit
：
When the ball reached the melting point,it is in a liquid state , if too long or too high temperature
and pressure,it will destroy surface tension of solder balls and the supporting role, resulting in
short-circuit phenomenon when reflows,the chips fall entirely on the PCB pads the , so we need to
appropriately reduce the heating section of the third and fourth soldering temperature and time , or
reduce the bottom of the preheat temperature.
Note
:
In normal use rework station it will produce small quantities of bad smelly, in order
to ensure comfortable, safe and healthy operating environment, pleas keep indoor and
outdoor air flow.