Q
Quack
- Jan 1, 1970
- 0
After trying lots of different ways to mount SM chips, i think i have
found the easiest and fastest way, without applying to much heat to
the chip, or fiddling around under microscopes etc.
My boards are made using blue PNP on a 600dpi laser printer, and
etched with ferric chloride chrystals desolved in warm water.
First clean the board perfectly, using some cleaning alcohol (after a
good scrub in the sink to remove any discoloration). Once is nice and
shiny, apply a coating of 'flux 140' to the entire board.
This protects it from oxidization and also contains some flux to help
things along. (this can be purchased from RSWWW in UK, part#363-6539
£7.29).
Wait for this to dry completely (usually left overnight).
Now for the actual soldering;
Add a little solder to the iron, but only a LITTLE, just enough to
paint it - no blobs hanging off.
now use the iron to 'paint' the pads where the SM chip will sit - just
make them go silvery. If you prepared your iron properly, not using
too much solder, there will be no shorted pads, they should look just
like they started, except silvery.
now place the chip carefully (some people may need magnification here
like me , depending on the exact size of the chips) - now use
something like a pen or small screwdriver to press lightly on the top
of the chip holding it in place with one hand.
lightly and quickly touch the top of each pin using a clean SOLDERLESS
iron.
and presto - done!.
the solder on the pad itself heats fast enough to bond with the legs,
no shorts, no messy flux or solder removing braid.
and the chips dont even get warm! no damage.
checkout some example pictures here of the latest board i made using
this technique, works perfectly for me!
(i use a WELLER standard tip, nothing special for my iron)
www.quack.cc/board1.jpg
www.quack.cc/board2.jpg
www.quack.cc/board3.jpg
www.quack.cc/chips.jpg
I may take some snapshots and make a step-by-step html page for the
next board i make. But i think its pretty self-explanatory, but
perhaps for a begining to end kind of guide.
Good luck
found the easiest and fastest way, without applying to much heat to
the chip, or fiddling around under microscopes etc.
My boards are made using blue PNP on a 600dpi laser printer, and
etched with ferric chloride chrystals desolved in warm water.
First clean the board perfectly, using some cleaning alcohol (after a
good scrub in the sink to remove any discoloration). Once is nice and
shiny, apply a coating of 'flux 140' to the entire board.
This protects it from oxidization and also contains some flux to help
things along. (this can be purchased from RSWWW in UK, part#363-6539
£7.29).
Wait for this to dry completely (usually left overnight).
Now for the actual soldering;
Add a little solder to the iron, but only a LITTLE, just enough to
paint it - no blobs hanging off.
now use the iron to 'paint' the pads where the SM chip will sit - just
make them go silvery. If you prepared your iron properly, not using
too much solder, there will be no shorted pads, they should look just
like they started, except silvery.
now place the chip carefully (some people may need magnification here
like me , depending on the exact size of the chips) - now use
something like a pen or small screwdriver to press lightly on the top
of the chip holding it in place with one hand.
lightly and quickly touch the top of each pin using a clean SOLDERLESS
iron.
and presto - done!.
the solder on the pad itself heats fast enough to bond with the legs,
no shorts, no messy flux or solder removing braid.
and the chips dont even get warm! no damage.
checkout some example pictures here of the latest board i made using
this technique, works perfectly for me!
(i use a WELLER standard tip, nothing special for my iron)
www.quack.cc/board1.jpg
www.quack.cc/board2.jpg
www.quack.cc/board3.jpg
www.quack.cc/chips.jpg
I may take some snapshots and make a step-by-step html page for the
next board i make. But i think its pretty self-explanatory, but
perhaps for a begining to end kind of guide.
Good luck