SMT soldering , lot of questions

sgrudu said:

so it seems that for PQF-208 packages I should forget manual soldering , right ?

Nobody talked about stencils... are they usually given by the pcb manufacturer ?

Thank you for all your replies !

Click to expand...

Do not forget about manual soldering of PQF packages. I have solderd a number of chips (QFP, TQFP....) useing the method described here:

https://www.jbc.es/english/cont/advanced/repairproc.html

I allso think that JBC is a verry nice brand.

Regards

Hi ,
Being in the service trade for quite some years, this is what i do regarding smd's.
To remove chips, I use aluminuim foil to cover the board, then using a razor, I cut out the outlay (pressing against it makes a stencil on the foil)of the chip to be removed from the foil, leaving just the chip viewable. With a hot air gun I then remove it, protecting the rest of the components with the foil.
Gently clean the PCB with oiless contact cleaner (Cramolin red can).
Center the chip to be resoldered.
Apply solder all along the sides of the chip.
Hold the board at a vertical angle, and from the top and moving downwards, heat the contacts.
The solder will drip right down to the last contacts, leaving the rest nicely soldered.
The remaining 2-3 contacts on each side can be easily seperated by the use of solder wick.

I use a normal (fairly thick) soldering tip on a jbc 40w soldering station.

sda