Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

BGA Rework

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BGA Rework | 25 August, 2006

Hi Folks, When temp profiling bga rework how important is thermocouple placement. Have read that holes should be drilled from board underside into ball to accomodate probe (isn't theory wonderful). Probably ok for high volume rework but for 1 or 2 off devices then not practicle. For small pitch BGA's or CSP's can't always get a probe under the device. Any advice.

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BGA Rework | 25 August, 2006

When not practical to drill hole into pcb to profile here is what I do and seems to be just fine.

place thermo into area underneath BGA and let her rip, you will not be in the ball/solder joint, but the temp difference as long as you are in the array somewhat is not that different. just keep in mind that is showing hotter than actual at solder joint level (I see about 10 C with my equipment). Always remember that there is tolerance in temps! You will always know when you have reached the melting point of solder. I allow T/C temp to hit 225 (63/37)for this method.

When that is not viable, I just pick a profile based on experience with my equipment and diff thermal masses and start a removal process after part becomes loose I add the proverbial 20 secs and that is what I use for install profile of same device.

hope it was helpful


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