Reballing bga's

Discussion in 'General Electronics Chat' started by MBVet05, Apr 21, 2012.

  1. MBVet05

    Thread Starter New Member

    Jul 21, 2011
    27
    1
    So, I have been searching for a good way to remove and replace a BGA. Nothing in particular. Just want to practice.

    However, I have been having little success. Since I have no automated machines to pick and place and no x-ray methods after I am done with the process I am stuck using non traditional methods of removal and replacement.

    Right now I am using hot air and a pre-heater on the underside of my proto board. Since BGA's are extremely difficult to remove I have destroyed a few practice boards trying this method.

    I was successful only once out of 4 tries.

    If anyone has a better method I would love to read your success story.
     
  2. chrisw1990

    Active Member

    Oct 22, 2011
    543
    41
    you could try buying a station? the cheap ones on ebay cost £100.. but if your practising this may be too much, but bgas are worth a lot more..
     
  3. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    Google reflow oven.....;)
     
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    Damn you sure picked a hard one to start with.

    Problem one is removing the BGA without destroying both it and the PCB underneath. How difficult that is depends on if the PCB has parts on both sides. If not, a hot plate can pre-heat the board to near the melting point, then a hot air stream can puch the BGA over the melting point so tweezers or a vacuum pick can remove it.

    I would worry my vacuum pick tips would melt so I'd use big tweezers.

    Simple solder wick can remove the solder from both PCB and BGA. I recommend the pre-fluxed kind to the point I don't use non-fluxed.

    To reball a BGA, just get yourself some real balls. EBay lists them in little jars by the 10,000's. Flux the BGA, pour on some balls, and push into place with tweezers. You don't need to be very accurate as surface tension will draw the balls to dead spot on Occasionally two balls will join to make one huge ball, and huge balls are undesirable, so wick it off and add two normal balls to the two pins.

    Any hot air reflow will get your balls down.

    Now you have a good PCB and good BGA, slap B onto A and you go back, Jack, and do it again.
     
  5. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,535
    I used to service these machines. They had a special tool involving a prism and hot nitrogen to do it. Basically the prism allowed the operator to recenter the chip on the PCB board, which is the hardest step.
     
  6. MBVet05

    Thread Starter New Member

    Jul 21, 2011
    27
    1
    I have not tried using the pre-made solder balls. One method I tried that worked somewhat well was using a pick and placing solder paste on each pad. Then I would use the hot air pencil to flow it into place. I also tried with some flim forms from solder.net that worked fairly well.

    The biggest problem I see with using these methods is that you have no way of knowing if the solder flowed correctly to all pads since you cannot inspect underneath. I usually do a circuit check afterward to make sure all connections are working.

    An x-ray would be ideal. But, for my prototyping purposes the cost is not practical.