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Soldering surface mount components

  • Thread starter Daniel Kelly \(AKA Jack\)
  • Start date
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Daniel Kelly \(AKA Jack\)

Jan 1, 1970
0
Hi,

I am planning a job where I need to manually solder surface mount ICs. Some
of these ICs have pins that are only 0.5mm apart! I'm worried that this
will be impossible to solder manually.

I've looked on the web - people tell me it is possible to solder SMDs but
I'm worried their talking about older SMDs with pin-to-pin distances of more
like 1mm.

I'm a relatively skilled soldering iron user.

Is it possible to manually solder ICs with pins only 0.5mm apart?

Thanks,
Jack
 
C

Charles Schuler

Jan 1, 1970
0
Daniel Kelly (AKA Jack) said:
Hi,

I am planning a job where I need to manually solder surface mount ICs. Some
of these ICs have pins that are only 0.5mm apart! I'm worried that this
will be impossible to solder manually.

I've looked on the web - people tell me it is possible to solder SMDs but
I'm worried their talking about older SMDs with pin-to-pin distances of more
like 1mm.

I'm a relatively skilled soldering iron user.

Is it possible to manually solder ICs with pins only 0.5mm apart?

1/ Magnification
2/ Liquid flux and solder paste
3/ Hot air soldering device
4/ Practice and patience
 
M

Mariano

Jan 1, 1970
0
1/ Magnification
2/ Liquid flux and solder paste

How do you apply the solder paste manually to the IC pins or pads ? I've
tried and the paste does not stick anywhere (before soldering). I even tried
with a syringe and ended up clogging the needle.

IMO this is the most critical part in SMD. It doesn't matter if your
placement is poor, since the solder will try to align the components with
the pads (when soldering). But you need to apply an even coat (and right
quantity) of paste to each pad. This is were I fail.
 
I

Ian Stirling

Jan 1, 1970
0
In sci.electronics.design "Daniel Kelly \(AKA Jack\) said:
Hi,

I am planning a job where I need to manually solder surface mount ICs. Some
of these ICs have pins that are only 0.5mm apart! I'm worried that this
will be impossible to solder manually.

To add to this, is it possible to buy smaller diameter than normal solder?
I've found I can make my own, with a drawplate, but it is a tedious process.
I ahven't found anywhere that stocks under .5mm multicore.
 
R

Repzak

Jan 1, 1970
0
Is it possible to manually solder ICs with pins only 0.5mm apart?

Hey

Yearh.. i did it last week with a Tusb6250, on a home etched pcb...

u just used some quite thin solder and a lot of flux....

i thing my tip on the solder iron is 0,5 times 1mm ... but as long as there
is a lot of flux and you dosent use much solder i runs nice... and maybe use
"solder remover litze" with added flux to remove some of the solder there is
to much...


normally i just put litle solder on the solderiron tip and flux on the IC
legs, and then the flux will attrack the solder to the legs...


you could find some old computer stuff and remove some of the ic's with hot
air and use then as test, before using an expensive ic

Kasper
 
M

Mjolinor

Jan 1, 1970
0
Ian Stirling said:
In sci.electronics.design "Daniel Kelly \(AKA Jack\)"

To add to this, is it possible to buy smaller diameter than normal solder?
I've found I can make my own, with a drawplate, but it is a tedious process.
I ahven't found anywhere that stocks under .5mm multicore.
I just flatten it with pliers then cut it lengthways.
 
M

Mark (UK)

Jan 1, 1970
0
Hi!

How I do it, is once the chip is removed, and you've got the bare pads,
I then use a regular iron set to a low temp, 275-300, to go over the
pads with fresh LMP solder and lots of flux, that tinns them up,the flux
helps stop them joining together, and leaves solder on each pad to help
solder the new IC legs to. Then use a hot air pencil to finally solder
the chip in place.

Yours, Mark.
 
J

John Larkin

Jan 1, 1970
0
How do you apply the solder paste manually to the IC pins or pads ? I've
tried and the paste does not stick anywhere (before soldering). I even tried
with a syringe and ended up clogging the needle.

Paste isn't necessary. Flux the pins (liquid, maybe diluted RMA rosin
flux) and apply a small glob of solder to the tip of the iron. Run the
tip down the pins, at the pin/pad junctions; solder will magically
wick off the tip onto the pins. There are special "hoof" tips with a
beveled flat that holds a nice little pool of solder to make this work
better.

Tack two corner pins first, then just run down the line. Works great.

John
 
I

Impmon

Jan 1, 1970
0
Is it possible to manually solder ICs with pins only 0.5mm apart?

Yes it can be done, just use fine point, magnifying glass, and use
little solder.

It'd be easier to leave such tiny work to machines. Why do you need
to solder them manually?
 
C

Chuck Olson

Jan 1, 1970
0
Daniel Kelly (AKA Jack) said:
Hi,

I am planning a job where I need to manually solder surface mount ICs. Some
of these ICs have pins that are only 0.5mm apart! I'm worried that this
will be impossible to solder manually.

I've looked on the web - people tell me it is possible to solder SMDs but
I'm worried their talking about older SMDs with pin-to-pin distances of more
like 1mm.

I'm a relatively skilled soldering iron user.

Is it possible to manually solder ICs with pins only 0.5mm apart?

Thanks,
Jack
As mentioned, you need magnification. The first thing you should invest in
is a binocular microscope with variable power from 7 to 30 diameters and a
socket for a spotlight. If you can see it, you can do it. You should be
able to find a used one for about $200, (try Ebay) (and another $25 for the
spotlight) and it will last your whole life. You will be astounded at what
you can see with that microscope - - from examining today's almost invisible
electronic components to removing slivers and hangnails, and learning about
tiny creatures. Nobody should be without one.

The next thing you need is a soldering iron that allows your fingers to get
within about 1.25" of where the soldering is happening so that you have as
good control of the soldering tip as you have of the tip of a pencil when
you write. I find the Metcal stuff works very well, and older used systems
are available for under $100 on Ebay. Finally, you should be able to find
some 0.020" diameter solder (try Ebay or a big electronics flea market).

I made a surface-mount component clamp for my microscope consisting of a
strip of springy phosphor-bronze or beryllium-copper between two standoffs
about 3 inches apart and a piece of #12 wire soldered at the middle of the
strip to form a "T" so it pokes almost into the field of view of the
microscope, and finally a piece of #20 solid wire soldered at the end of the
#12 arm and bent down so the tip of the wire presses on the component you
want to solder right in the middle of the field of view. Just pull up on
the spring-supported #12 arm when you want to move the assembly or lift it
up onto another component.

Good luck,

Chuck
 
D

Daniel Kelly \(AKA Jack\)

Jan 1, 1970
0
Hi,
It'd be easier to leave such tiny work to machines. Why do you need
to solder them manually?

I'm building a one-off design for a psychology PhD experiment. I do have
access to University College London's Electrical Engineering department but
I doubt they have robots for building surface mount systems.

Oh, and I have looked long and hard for 'normal' sized chips but they just
don't exist for the sort of application I need.

Thanks,
Jack
 
D

Daniel Kelly \(AKA Jack\)

Jan 1, 1970
0
Excellent, thanks so much for all the help, everyone.

Jack
 
T

Tim Auton

Jan 1, 1970
0
Daniel Kelly \(AKA Jack\) said:
I'm building a one-off design for a psychology PhD experiment. I do have
access to University College London's Electrical Engineering department but
I doubt they have robots for building surface mount systems.

They will have technicians, lecturers and students who should know
what to do though. Ask nicely and someone might give you a
demonstration and show you the tools they have available.


Tim
 
P

Product developer

Jan 1, 1970
0
Daniel Kelly \(AKA Jack\) said:
Hi,

I am planning a job where I need to manually solder surface mount ICs. Some
of these ICs have pins that are only 0.5mm apart! I'm worried that this
will be impossible to solder manually.

I've looked on the web - people tell me it is possible to solder SMDs but
I'm worried their talking about older SMDs with pin-to-pin distances of more
like 1mm.

I'm a relatively skilled soldering iron user.

Is it possible to manually solder ICs with pins only 0.5mm apart?

Thanks,
Jack


Antex low watt iron with fine tip. Use a flux pen to paint flux onto
pads. Using tweezers hold the I.C. in place and tack the corner pins.
Apply just enough solder to iron tip to wet it and flick off excess.
Apply the tip very briefly to the pin end and pad and the solder will
wick into and between the pin and pad. When removing a chip without
heat simply take a sharp Xacto blade and carefully apply pressure to
the blade onto the pins as near to the chip body as possible. This
will sever the pins from the chip body making them easier for removal
without lifting a pad. Be careful to not exceed the pin / chip body
with the knife or you will risk opening a trace. I have been doing
this for years and have lost a trace or pad in over twenty years.
 
G

Gordon Youd

Jan 1, 1970
0
I have a VHS video demonstrating METCAL Soldering Systems.

They make SMT rework by hand look so simple, like John Larkin said "tack the
ends and run down the line".

Try CPC Ltd for a copy of the video, it's free.

If you cannot get a copy I can copy mine for you.

The site for Metcal is www.metcal.com, I could not find the video there
but electronic wholesalers have it.

Regards, Gordon.

Remove the Z from my address to reply.
 
R

Rene Tschaggelar

Jan 1, 1970
0
Mariano said:
How do you apply the solder paste manually to the IC pins or pads ? I've
tried and the paste does not stick anywhere (before soldering). I even tried
with a syringe and ended up clogging the needle.

I have Flux inside a syringe with a 1mm needle. Before application i
heat the syringe and the flux with the heatgun to 80 degC or so.

The solder past also comes in a syringe that needs to be heated before
use. I prefer the 1mm tin wire though. Tin paste is a mess.

Rene
 
R

Rene Tschaggelar

Jan 1, 1970
0
Daniel said:
Hi,

I am planning a job where I need to manually solder surface mount ICs. Some
of these ICs have pins that are only 0.5mm apart! I'm worried that this
will be impossible to solder manually.

I've looked on the web - people tell me it is possible to solder SMDs but
I'm worried their talking about older SMDs with pin-to-pin distances of more
like 1mm.

I'm a relatively skilled soldering iron user.

Is it possible to manually solder ICs with pins only 0.5mm apart?

Yes. Sure.

For magnification I recommend strong reading glasses. I use 4 dioptries.
That let me have it as close as 15cm from my eyes.

Then I use fluxpaste from a syringe, heated with the heatgun to make it
more liquid.

And medium tip iron plus 1 mm or 0.8mm tim wire.

First come the fixng phase where two diagonal corner pins are soldered
down. It doesn't matter whether the adjacent pins are soldered too.

Don't even try to solder a single pins. A few of them at one is ok. The
flux separates the tin on the pins.
Oh, yes, having a soldermask helps.

Rene
 
M

Mariano

Jan 1, 1970
0
Can anybody point me to any flux and paste product in the US ? I checked
Newark products and they are quite expensive. And since I have no experience
with flux/paste, I don't want to screw up buying something useless.

Thanks.
Mariano
 
P

Paul Guy

Jan 1, 1970
0
Hi,

I am planning a job where I need to manually solder surface mount ICs. Some
of these ICs have pins that are only 0.5mm apart! I'm worried that this
will be impossible to solder manually.

I've looked on the web - people tell me it is possible to solder SMDs but
I'm worried their talking about older SMDs with pin-to-pin distances of more
like 1mm.

I'm a relatively skilled soldering iron user.

Is it possible to manually solder ICs with pins only 0.5mm apart?

Thanks,
Jack
The pads MUST NOT have any applied solder on them. If they do,
remove it all with solderwick. (the bumps from the solder will not
allow the chip to lie flat.)
Align the IC, solder one corner pin to hold it down. Solder the
opposite corner down. Don't worry if the solder joins several pins.
Make absolutely sure it's aligned properly, and all the pins are
resting on the pads. Now apply enough solder that all the pins are
covered, even if they are all shorted together.
Here's the neat part: Take some "solderwick" (the braided stuff you
use for removing solder) and remove all the solder! It doesn't really
take it all off, it leaves the required amount underneath the "feet"
of the pins. If you look in a microscope, you'll find that you have
almost perfectly soldered pins. There will be trouble if the pins
didn't all touch the pads prior to soldering. Chips intended for
surface mount must have good co-planarity, so be very gentle handling
them. If you bend the leads for than a few thousands of an inch, you
can expect trouble.
If you have a good touch with an iron, and are using good liquid
flux (RMA type, you must remove the residual flux afterward using a
solvent like isopropyl alcohol), you can zoom thin solder along the
pins, and it will not short them out. I believe it's absolutely
necessary to use the proper liquid flux in order to pull this off, and
it does need a bit of practice. You'll need the solderwick to remove
shorted pins. I figure if you're using solderwick anyhow, then do the
first method and not lose any sleep over it.
I have successfully soldered QFP80's this way, the most difficult
part is the alignment to the pads.
This is not a fast way to solder, but it doesn't need any fancy
equipment.
To show how crude you can get, instead of using our hot air reflow
stations (several thousand $ each), I demonstrated soldering a QFP80
using an old crappy soldering GUN, along with the solderwick removal.
The final results were just as good, under close inspection with a
microscope, and they easily met the IPC/EIA J-STD-001C soldering
standards. (Don't do this with a good chip! The soldering guns can
damage chips because of electrostatic discharge (ESD) from the
capacitive coupling to the power line.)

-Paul
...............................................................
Paul
Somewhere in the Nova Scotia fog
ANTISPAM - Please remove the m's in my email address
 
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