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BGA welding method for lead free bridge
BGA welding method for lead free bridge
1. for lead-free motherboard, remove the first in the oven to bake 100 degrees Celsius, time is generally 2
to 3 hours (this is the shortest time, the factory in general BGA are more than 10 hours) of course into the
main board of water to wash with hot water to clean the ultrasonic wave, the dust will be a bit of a shock.
2. Why going to bake the motherboard. The reason is that have long-term customers do not have books
the, suddenly take out starting point does not shine, weather, environment will cause the motherboard or
wet, this time you direct access to the motherboard into the BGA rework station, directly heated from
bridge, temperatures up to 250 to 270, local heating, and other places do not heat, plus the bridge piece
somewhat humidity, easy to cause the deformation of the motherboard, so even if the BGA well is not stable.
3. Lead the bridge pieces generally, we have used 280 degrees take, tweezers to wait, see Xizhu shiny struck
lightly with tweezers, active use tweezers to pick up, in general can successfully take down, pads on the
motherboard directly to wipe solder paste help then iron gently scraping flat welding (do not use suction
tin wire to drag, easy to absorb tin wire sticking to pad in the iron to heating easy to solder together off)
and then apply solder paste, pay attention to smear evenly. Not too much to melt beads.
4. bridge chip suction tin wire leveling alcohol wiped clean, set the beads (Wu Qian), should pay attention
to is, I use air gun wind 3 to 4, between 4 to 5 and then the first temperature, from the right corner blowing,
blowing to rotate the upper right corner of the air gun, the bridge piece is 4 to the distance 5 cm, when you
see the shiny beads returned to solder joints, then continue to rotate a blow to the upper left corner, the
rotation of the amplitude can be large (not circles) and then blow down to the lower right corner, then the
beads easily melts into the solder joint on the other hand, of course, is tweezers must see, must use the
tweezers to separate them to stick together in the ball, or post up (the bridge will be very troublesome
beads blowing bulging or burst).
5. Successfully blowing up the bridge after if not ideal, cold bridge until after the meeting point of solder
paste (note not completely cooled down, but also a little temperature), in a uniform heating, Xizhu homing
to the solder joint is good, aligned position it into the motherboard to BGA... Of course if a bridge piece by
too close to with tinfoil other bridge piece cover or scrapped the CPU into the bridge. The following infrared
heating can also with foil to block, motherboards with fixation and good without fixation with other things
pressure can not be firmly shaking.
TAG:  BGA welding BGA rework station BGA Solder Joints reflow soldering PCB plate solder lead solder