For BGA reflow experts...

[Davi.p]

I have attempted all sumed very few reflow processes, and i need to make it better, how do you make yours to have sureness that the balls are really fully reflowed? My temptation was always to do "the slight move" touching very gently an angle, but due to some cases, but maybe 100%, where the previously half working device became totally shut off, i finally understood that the damn "move" makes the balls shorted, so what do you suggest?
Thanks!.. Muchas gracias..

[EazyBone]

Flux, don't touch it just reheat it. It'll reseat itself. The professional machines never touch the chip.

But we know, I ain't no expert.

[Davi.p]

Never satisfaction to talk with you.. i ask to other users, this evening YouTube proposed me a video of Nick's TVs, that he is not exactly the last of the donkeys, where he talk about reflow techniques, he said the right way to ensure the balls reflowing (every) is on top the gentle touch of chip to see it move, i asked him where i do wrong, if i touch the corner instead of the side center, the sequence of the reflows i made tells all the times i made the move, the device became totally dead instead of defective as before.. it 's clearly wrong the way i touch.. the balls fuses together..

[SMDFlea]

The last 2 posts deleted. cool it please. Have a sensible discussion.

[harp]

if i touch the corner instead of the side center.................. in videos of northwestrepair he noted that bga ic must be gently touched on side center, and not touched on corner.

[the Benninger]

Generally I do the following, depending on the case I clearly do it when they are small and light, after preparing everything when placing the Vga circuit I leave it slightly tilted in this way when melting the tin the piece sits by itself I get very good results with this

[Davi.p]

The benninger, i agree with your method, i used it myself, the problem here is i was meaning reflow of the chip without reballing and same old chip..

[the Benninger]

Hi Davi.p, thanks so much in the cases that I have done it, it has always been doing rebaling many times due to the need to change the alloy, and it has happened indifferently whether I change the component for a new one, or when there is no need to do so, what is almost a norm for me is to change the laeation during reballingThe choice of alloy I take based on the function of the VGA itself, taking into account the maximum temperature at which it can work are variables that help you decide.

my answer is to use a very biscuit Flux whatever your preference is, and use a pre heater in conjunction with a heat gun, this for large and heavy VGAs you have to have a lot of experience and a neurosurgeon's pulse, and finally I give small lateral touches very soft but enough to move about 0.25mm you know very slight but that you can barely observe, I wonder if there is some kind of vibration generator that will help in that but I don't know if there is

In the case that it is rectangular like a notebook processor I choose one of the longest sides I position myself right in the middle of this side and give small and soft thrusts in the way I already mentioned, since it is completely square I don't care from which side I do it, in any case I always try to be comfortable in an ergonomic position if possible with the space around it well cleared, I even do some relaxation techniques breathing ect, this is also one of the reasons why I do not consume alcoholic beverages unfortunately

[Davi.p]

Ehi! My compliments for the complete and clear explanation, it's been very helpful, i consider myself ready for the next reflow attempt, good evening!