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Originally Posted by buschell thanks anyway,most of what u say are correct.i work on some and they do work at lesat60%.4 example removing ic and checking 4 broken ball,afer doing that,d problem of reballing,and after putting d ic back to make it work again is my most problem.i can read chart properly.i will be happy if you have visual aid. |
So ... this is not so hard as you mean
1. You should choose temperature correctly ~250-300C
2. Before you start heat up the chip first preheat hot air tool 2-3 minutes
3. You should choose time correctly (otherwise you can overheat IC), you must heat up chip not so long,the best way to define that chip can be removed or it was already soldered is a easy movement of the chip under influence of a air flow (you can see it under microscope), it means that solder completely has fused, time about 1-2 minutes from a start of heating(depend on size of chip and PCB configuration)
4. For soldering back time about 0.5-1 minutes
5. For reballing i choose temp. ~200-250C, for first, study on old or damaged ICs, and i sure after some quantity you will do it fast and with good quality
WBR
Max