Best Method to Align Small IC while replacing

[IamPritesh]

It usually takes a lot of time to place a new chip perfectly. For example (charging ic or 3/5V IC ). I understand lots of practice is required but I was wondering what is the best method you use .Which hand do you use to hold the heat air blower and so on.


Thanks

[mcplslg123]

Re: Best Method to Align Small IC while replacing

It depends on practice as you have already said. Its important to use good quality flux so that the ic gets it to place when heated even though not aligned very perfectly.

[IamPritesh]

Re: Best Method to Align Small IC while replacing

It depends on practice as you have already said. Its important to use good quality flux so that the ic gets it to place when heated even though not aligned very perfectly.

Which flux do you use ? Do you grip the IC with the help of a Tweezer while you apply heat ?

[anshad]

Re: Best Method to Align Small IC while replacing

It usually takes a lot of time to place a new chip perfectly. For example (charging ic or 3/5V IC ). I understand lots of practice is required but I was wondering what is the best method you use .Which hand do you use to hold the heat air blower and so on.


Thanks

Which hands to use depends on what you feel comfortable. Try yourself using both hands and which one you feel unshaken and steady while doing the job, stick to that one. Refer the below video, its the way most of the professionals solder QFN chips

https://www.youtube.com/watch?v=c_Qt5CtUlqY

[mcplslg123]

Re: Best Method to Align Small IC while replacing

Which flux do you use ? Do you grip the IC with the help of a Tweezer while you apply heat ?

I use AMTECH flux. No i dont grip the ic while applying heat.

[IamPritesh]

Re: Best Method to Align Small IC while replacing

I use AMTECH flux. No i dont grip the ic while applying heat.

This one ?
https://www.amazon.in/Generic-O2IBG-.../dp/B01FA6G4B2


What is Solder Paste ? I see in many videos,people are applying some grey paste like substance on the board before placing the IC.

[dellxps15]

Re: Best Method to Align Small IC while replacing

soldering back a small qfn need to study the situation. if i remove for example a 3.3 5v ic, i use flux to remove it, and without clean old solder i go for the new one. when heating the board i then press a bit the ic on pcb. when all joint get connected ull see that the chip stay in place alone. if needed i keep a small pressure over it with tweezer till it get cold enought and soldered perfect. after that i use a small iron tips to pass all the corner and joint with flux and solder.

if u remove an ic, then clean the board with flux and solder wick u can apply a small amount of solder on pins and center pin. then when soldering new chip use good flux, apply a good pressure on the chip till it get all extra solder out of it. keep pressing with tweezer till it cold down. with a solder tips remove extra solder from corner and get a pass on all side of ic. ur done.

as for centering the ic, if u have a magnifier lamp with led illumination ull be just fine centering it perfectly.

practice a bit and ull be the master of qfn soldering

for flux i use kingbo but also amtech 559 (green bottle) is ok, but it need to be original, not fake.

[dj_ricoh]

Re: Best Method to Align Small IC while replacing

This one ?
https://www.amazon.in/Generic-O2IBG-.../dp/B01FA6G4B2


What is Solder Paste ? I see in many videos,people are applying some grey paste like substance on the board before placing the IC.

do you know what is paste? well, solder paste!

PASTE -a thick, soft, moist substance typically produced by mixing dry ingredients with a liquid.

[IamPritesh]

Re: Best Method to Align Small IC while replacing

do you know what is paste? well, solder paste!

PASTE -a thick, soft, moist substance typically produced by mixing dry ingredients with a liquid.

Why does anyone use this if we already have a good flux. Is solder flux enough?

[IamPritesh]

Re: Best Method to Align Small IC while replacing

soldering back a small qfn need to study the situation. if i remove for example a 3.3 5v ic, i use flux to remove it, and without clean old solder i go for the new one. when heating the board i then press a bit the ic on pcb. when all joint get connected ull see that the chip stay in place alone. if needed i keep a small pressure over it with tweezer till it get cold enought and soldered perfect. after that i use a small iron tips to pass all the corner and joint with flux and solder.

if u remove an ic, then clean the board with flux and solder wick u can apply a small amount of solder on pins and center pin. then when soldering new chip use good flux, apply a good pressure on the chip till it get all extra solder out of it. keep pressing with tweezer till it cold down. with a solder tips remove extra solder from corner and get a pass on all side of ic. ur done.

as for centering the ic, if u have a magnifier lamp with led illumination ull be just fine centering it perfectly.

practice a bit and ull be the master of qfn soldering

for flux i use kingbo but also amtech 559 (green bottle) is ok, but it need to be original, not fake.

Thank you sir. That is very insightful.

[mcplslg123]

Re: Best Method to Align Small IC while replacing

Getting a original flux is pain-most are chinese crap where some portion of the original flux is mixed with grease and sold as original. @pritesh, you are based in India and can buy it from Nehru Place,New Delhi instead of buying online. If you need contact info PM me, I'll give you contact number of vendors in New Delhi where you can get original Flux.

[KvnTM]

Re: Best Method to Align Small IC while replacing

I usually draw the outline of the chip onto the board before removing it when there is no silkscreen. Surface tension of the solder will do the rest. Good flux is also very important.

[IamPritesh]

Re: Best Method to Align Small IC while replacing

I usually draw the outline of the chip onto the board before removing it when there is no silkscreen. Surface tension of the solder will do the rest. Good flux is also very important.

Interesting. What do you use to draw the line that doesn't wipeaway when you clean the area before seating the new chip?

[KvnTM]

Re: Best Method to Align Small IC while replacing

Interesting. What do you use to draw the line that doesn't wipeaway when you clean the area before seating the new chip?

It really depends on the chip. Usually a normal pencil does the job and careful cleaning with a q-tip.

UV solder mask also works for this kind of stuff. It is available in many colors. It won't wipe away and is somewhat permanent. Just put tiny drops on the corners of the chip and cure it.

[jasko_jacker]

Re: Best Method to Align Small IC while replacing

I have tried many flux, I use three types:
Insat Hight Activity Rosin to remove bad bga
Insat VOC-Free water to inject under BGA for reflow
But the best for small component or reballing is
ERSA Fluxpaste F-SW 32, leaves no residue after the
welding, excellent activation point, even if only with
infrared