Author Topic: Questions regarding solder paste dispension, cleaning flux residue  (Read 139 times)

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Offline soFPG

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  • Country: de
Hello forum,

I just finished the building of my own reflow oven this week (based on Controleo3).

I don't have stencils for my PCBs so I had to distribute the solder paste manually with a toothpick for my first project. This

a) took a long time and
b) is difficult to do for TQFP and similar footprints.

So I basically dispersed solder paste all over the pins.

I put the PCB in the oven - SMD caps looked nice after reflow but there were a lot of solder balls floating around the TQFP IC. Because this probably leads to shorted pins in the future I drenched everything in flux and manually resoldered the TQFP package with my soldering iron to remove the tiny solder balls and also to make sure that every pins is connected properly.

After that my PCB looked really ugly because of all the flux (I want my PCBs to look nice). I then put some isoprob. alcohol on a Q-tip and rubbed the flux away which didn't work as well as I hoped.

Any tips on how to avoid the tiny solder balls after reflow and how to properly clean a PCB from flux / dirt (I have seen some Youtubers using ultra sonic cleaning stations but I don't know if they are expensive or not or which model they are using at all?).

Thanks so much  :)


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