Lead-free bridge piece of graphics

Lead-free bridge piece of graphics

1.For lead-free motherboard, remove after the first in the oven to bake, 2 to 100 hours, the time is generally

3 to 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 use hot water to wash do ultrasonic, the dust corrosion of a few debris shock.

2.Why going to bake the motherboard. The reason is that have long-term customers without books,

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, and the bridge piece somewhat

humidity, easy to cause the deformation of the motherboard, so even if the BGA well is not stable.

3.Lead-free bridge pieces generally, we have used 280 degree, 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.The bridge with 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 distance is 4 to 5 pieces of bridge 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 one hand, of course, also must be tweezers

see, will use tweezers to separate they were glued together with the ball, or post up (the bridge will be very

troublesome beads blowing bulging or burst).

5.Successful blow the bridge piece 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.