Removing cemented on SMD chips

[Audiorepair]

I tried to remove an unavailable IC from a donor board to fit onto another board.
(28 pin DIL SMD)

Trouble is, the IC's are glued onto the PCB, and after a huge amount of hot air, it still wouldn't dislodge.

Eventually I gave up as probably having destroyed the chip, and lifted every pin, when I was then able to chisel the IC off the board, revealing the 2 blobs of cement.



How could you possibly get such a glued chip off the board without damaging it?

[ambrosia heart]

Use them.  Despite  expensive,  it is  worthy and trustworthy for tech to own.  Hot air gun lifts off pads if temp is too high or too low.  An authentic BGA rework station avoids this situation. When reflow curve reaches max on screen, tech removes chip easily.

[wraper]

How could you possibly get such a glued chip off the board without damaging it?

Heat it until solder melts. Then rotate it with pliers instead of trying pulling it up. Breaking adhesive by shearing is much easier. It's best to use hot air in combination with preheater so solder does not solidify at the moment when you stop blowing hot air to use pliers.

[wraper]

An authentic BGA rework station avoids this situation. When reflow curve reaches max on screen, tech removes chip easily.

Did you ever do any rework to claim this? Removing small chip with such IR station is not only way more difficult but is also more damaging to PCB. Do you not see "BGA" in the title?

tech removes chip easily.

Really? Please explain this magical mechanism by which IR station undoes the adhesive.

[amyk]

If you are not interested in saving the board, then turn it over and mill it out from the back.

Don't remove the chip from the board, remove the board from the chip

[_Wim_]

Did you ever do any rework to claim this? Removing small chip with such IR station is not only way more difficult but is also more damaging to PCB. Do you not see "BGA" in the title?

I have on off these. I agree these do not help for a cemented chip, but these are also not only useful for BGA. To remove large chips with many pins (like for example DSPs) they are already really handy. For smaller chips I have the bottom section only as a pre-heater, and use a normal hot air station on top.

As explained above, twisting instead for cemented chips is a good option. If possible, try to use a pre-heater together with a hot air gun, it makes life easier. Any cheap pre-heater solution will do.