sethnintendo said:
Yep that is basically it. I used to work at Flextronics and I did numerous positions such as basic tester, ECN operator, and BGA operator. While I was doing BGA that is basically what we did. We had these huge machines that had different shapes of nozzles for different size chips. It was basically like a blow drier but more accurate. The bottom (where you place the board, we used little metal things that we would put on the edges up the board to prop it up because if it layed on the bottom heater it would warp the board) would heat up and the heat from the nozzle would make the solder flow (we had to paste the solder on using stencil type things). I am not too sure what the exact temp were but they were probably in the range of 230 or more. We then had to check each board (Cisco) using a x-ray machine to make sure the solder was connected at each point and no bridges on the chip we replaced. We removed and put new chips on using this method. The hardest part was actually putting the solder paste down correctly so it wouldn't bridge/etc since the stencils we used were sometimes warped due to use. The whole removing and putting on chips was pretty simple once you got the pasting down. |
That was as basic as I could get while still being informative lol. I envy you're reballing experience as I never worked with good enough equipment to reball and reinstall a chip. The solder generally has a melting point around 230 degrees for the 360 and PS3 due to the fact it's "lead free", older solder required less temperature to melt but was obviously more toxic hence it's ban. You of course would have your machines set to a higher temperature as you lose some heat transferring to the board/chip. Generally speaking you'd have over 300 degrees in your pre heater below and if you're on hot air the temperature depends upon your air flow. Reflowing boards would be so much easier if I'd had a good xray machine to confirm the reflow!







