30th April 2007 07:10 AM
Hot Air Rework
I'm doing a lot of hot air rework at work. Anyhow, I'm actually not familiar with the hot air station and what are the precautions that we need to take into consideration before performing rework, especially on IC.
I want to know whether we need to concern about the:
a) IC Package Peak Temperature (PPT) before rework?
b) Surrounding parts?
c) must perform pre-heat?
The types of hot air blower that I use is HAKKO 850B.
30th April 2007 04:07 PM
My Hakko heats the air to just above the solder melting temperature. I have not damaged any parts from too much heat. I use the small tip (mostly) and try to keep the air off other parts. I do not pre-heat.
30th April 2007 04:10 PM
I've done a lot of rework with a Hakko 850B. I think the datasheets for the IC's will have maximum temperature, etc. but I never looked any of it up. I just made sure I never held the hot air in one spot long enough to burn anything (well almost never! ) You can cook a board pretty quick with one of those.
Originally Posted by JEXLI
I only used the regular straight nozzle (about 5 mm opening). Never any of the special nozzles. It's possible to take a 120 pin LQFP off a board just using the regular straight nozzle.
Use Kapton tape to cover surrounding parts that you don't want to heat up too much. That stuff is amazing.
I never did any preheating. Just move the heat around and around the IC over all the pins until all the pads are liquid and flip the chip off the board with a pick. It's kind of an art-form that takes a while to learn. If you're removing something like a 48 pin TSOP just heat one side and lift that side off the board. Then heat the other side and the chip is off in seconds.
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