SSOP soldering
Michael
solder to solder these chips but I'm not consistent....I shake too darn
much. I'm batting about 50%.
Although I've been an electronics enthusiast for years I know absolutely
nothing about any soldering techniques other than my iron and solder.
Are there in fact, hot air tools that I could be using to solder the fine
pitch parts? Glue the part, and solder with hot air?
Can you simply use the solder that is already on the "solder plated" traces
to "reflow" and make a reliable connection to the chip? Or do you add
additional solder?
Do the surface mount chips have tinned leads?
Like I say, I have no experience whatsoever with any of this.
If there is a hot air system I could be using what can anyone recommend as a
"starter" system that could do one'sees and two'sees without alot of
expense?
THANKS
zwsd...@gmail.com
Michael wrote:
For onesies and twosies I would not bother with hot air equipment
unless you routinely need to remove and reinstall chips on the same
lands.
> I've been able to use the smallest tip for my weller and some ultra fine
> solder to solder these chips but I'm not consistent....I shake too darn
> much. I'm batting about 50%.
Use a flux pen liberally on the lands before putting down the
component. The object is to make the solder wet the land and lead and
use surface tension to keep the bead from sagging and shorting to the
next pin.
If you leave an individual joint hot for more than a few seconds, you
will boil the flux out of it and it will not flow properly. Add more
solder and use wick to get the excess off. Rosin-impregnated solder
wick is very helpful for this.
> Can you simply use the solder that is already on the "solder plated" traces
> to "reflow" and make a reliable connection to the chip? Or do you add
> additional solder?
HASL leaves enough solder on the surface to tack the chip down at the
corners but not to hold it down permanently, you need to add enough
solder to form a good fillet.
> Do the surface mount chips have tinned leads?
Depends on the process, particularly with evil RoHS bullshit producing
a new generation of problem parts. But you can rely on PbSn solder with
rosin core flux being able to wet the leads, which amounts to the same
thing.
Boris Mohar
At my age I need to use a stereo zoom microscope to see that stuff. I
prefer water soluble flux which I liberally apply over the IC pins covering
them completely. A small amount of solder is applied at the junction of the
pin row and the soldering iron (Metcal) tip. I prefer to push the tip
instead of dragging it. If you have enough flux three will be no oxidation of
the solder which kills the surface tension. It is the surface tension of
molten solder that caused it to snap back instead of forming unsightly rat
tail. Did I mention the you have to use plenty of flux? You can do the same
with rosin based solder and flux. Water washable flux has to be cleaned
immediately else left in air it reacts with humidity and polymerizes into
some weird goo that is hard to clean off. If you cannot clean the board
soldered using water based flux than store it in airtight container along wit
some desiccant.
--
Boris Mohar
Rene Tschaggelar
> On Tue, 6 Jun 2006 06:33:04 -0500, "Michael" <news...@yahoo.com> wrote:
>
>
>>I've been able to use the smallest tip for my weller and some ultra fine
>>solder to solder these chips but I'm not consistent....I shake too darn
>>much. I'm batting about 50%.
>>
>>Although I've been an electronics enthusiast for years I know absolutely
>>nothing about any soldering techniques other than my iron and solder.
>>
>>Are there in fact, hot air tools that I could be using to solder the fine
>>pitch parts? Glue the part, and solder with hot air?
>>
>>Can you simply use the solder that is already on the "solder plated" traces
>>to "reflow" and make a reliable connection to the chip? Or do you add
>>additional solder?
>>
>>Do the surface mount chips have tinned leads?
>>
>>Like I say, I have no experience whatsoever with any of this.
>>
>>If there is a hot air system I could be using what can anyone recommend as a
>>"starter" system that could do one'sees and two'sees without alot of
>>expense?
>
>
> At my age I need to use a stereo zoom microscope to see that stuff.
At my age, I prefer to use 3.5 or 4 diopter reading
glasses for 10$ from the supermarket. The advantage
over a microscpe is that I can adjust the distance
and angle by moving the head.
Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
John Larkin
wrote:
>I've been able to use the smallest tip for my weller and some ultra fine
>solder to solder these chips but I'm not consistent....I shake too darn
>much. I'm batting about 50%.
>
>Although I've been an electronics enthusiast for years I know absolutely
>nothing about any soldering techniques other than my iron and solder.
>
>Are there in fact, hot air tools that I could be using to solder the fine
>pitch parts? Glue the part, and solder with hot air?
>
>Can you simply use the solder that is already on the "solder plated" traces
>to "reflow" and make a reliable connection to the chip? Or do you add
>additional solder?
Tack down the chip by hand-soldering a couple of corner pins. These
joints can be mediocre. Make sure alignment is good.
Wet all the pins well with liquid RMA flux.
Clean your tip, add a little blob of fresh solder, and quickly run it
down a row of pins. Solder will wick off the tip and solder the pins
as you slide down the row. Hit the ugly corner pins as you pass.
They make "hoof" soldering iron tips that are optimized for this, with
a little flat area that stores a blob of solder.
John
RST Engineering (jw)
where we used a flux that had the appearance and consistency of water. Is
that the stuff you are talking about and where do you get it? What do you
clean it with?
Jim
"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
news:j87b82tvqig9bnrlc...@4ax.com...
AJ
"Michael" <news...@yahoo.com> wrote in message
news:JPidnfMl3P9t-hjZ...@comcast.com...
I have used a Pace soldering iron with a fairly large tip with a hole in it.
(I can't remember what its called now) You, tack the IC making sure
alignment is perfect, fill the hole up with solder, coat the pins with RMA
flux and run the iron down the pins. I have used this technique for a while
and find it very fast and easy.
Regards
AJ
Rich Grise
> I've been able to use the smallest tip for my weller and some ultra fine
> solder to solder these chips but I'm not consistent....I shake too darn
> much. I'm batting about 50%.
I've found that a nice hot toddy can calm your nerves a lot. ;-) I haven't
done those little bitty packages, but I have unsoldered and soldered SMT
resistors and capacitors (back in the days when you could actually see
individual components), But everybody seems to say, tin two pads on
opposite corners of the pattern. Flux them sparingly (like with a
syringe), set the chip down and hold it, then just touch each of the
corner leads (over the tinned pads) to sweat-solder them in place, then
flux the rest of the pins and just drag a solder ball over them - this
is supposed to work; I've never tried it but I can see myself doing it
as long as I had the right eyewear (like a 3X magnigier. ;-) )
Good Luck!
Rich
Rich Grise
> Boris Mohar wrote:
>> On Tue, 6 Jun 2006 06:33:04 -0500, "Michael" <news...@yahoo.com> wrote:
>>
>>>I've been able to use the smallest tip for my weller and some ultra fine
>>>solder to solder these chips but I'm not consistent....I shake too darn
>>>much. I'm batting about 50%.
>>>If there is a hot air system I could be using what can anyone recommend
>>>as a "starter" system that could do one'sees and two'sees without alot
>>>of expense?
>>
>> At my age I need to use a stereo zoom microscope to see that stuff.
>
> At my age, I prefer to use 3.5 or 4 diopter reading glasses for 10$ from
> the supermarket. The advantage over a microscpe is that I can adjust the
> distance and angle by moving the head.
>
> Rene
http://secure.transtronics.com/Optivisor.html
Cheers!
Rich
DJ Delorie
Rich Grise <rich...@example.net> writes:
> http://secure.transtronics.com/Optivisor.html
I have a set of these, but I got mine at woodcraft. The 3.5 power
makes 0805's look about a quarter of an inch long.
John Larkin
<j...@rstengineering.com> wrote:
>What is RMA flux, John? I took a little one day minicourse in SMD assembly
>where we used a flux that had the appearance and consistency of water. Is
>that the stuff you are talking about and where do you get it? What do you
>clean it with?
>
>Jim
>
>
Rosin, Mildly Activated. It's sticky, gooey, solvent-soluble,
non-conductive, brown/amber liquid, viscosity and color about like
maple syrup. You can dilute it a little with alcohol for the SSOP
soldering thing, maybe.
Clean with any nice solvent. We have a vapor degreaser with some
exotic 3M stuff in it. Most hand-washing is done with isopropyl
alcohol, although I like acetone, nasty and toxic as it is.
RMA flux is great. If you have a cruddy, dull solder joint, apply a
tiny dab and touch it with an iron, and it'll instantly get smooth and
shiny.
John
Nico Coesel
>I've been able to use the smallest tip for my weller and some ultra fine
>solder to solder these chips but I'm not consistent....I shake too darn
>much. I'm batting about 50%.
>
>Although I've been an electronics enthusiast for years I know absolutely
>nothing about any soldering techniques other than my iron and solder.
Use a hollow soldering tip and extra flux. A hollow tip will suck the
excess tin back onto the tip.
--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl
Michael
question was about "hot air".
Is there actually some sort of hot air system that will solder?
I've done everything you can think of with my iron and yes most of the time
I can do fine pitch parts with all the techiniques mentioned.....I'm looking
for info on "hot air" and reflow.
Rene Tschaggelar
Forget hot air.
Yes, there are hot air guns and there are reflow
boxes built from pizza ovens. But considering
the purpose, soldering prototypes, they are
compared with just an iron.
You'd have to go into paste masks, paste drying
up, this sort of hassles.
John Jardine.
Bloody SM ICs.
I use my normal Weller 50W 3mm chisel bit. Trick is to do the pins en-masse.
Freshly tin the PCB pads.
Force the IC body in position with something long and pointy.
Tack solder the outside corner pins.
Wipe tip clean.
Run down each side of the IC eith the iron.
SM IC pins fuse easily with the freshly fluxed and soldered PCB pads.
If I had any, I'd use some liquid flux but I don't, so I don't but as I'm
not seeing failures I don't make the effort.
john
AJ
"Rene Tschaggelar" <no...@none.net> wrote in message
news:4485ded9$0$709$5402...@news.sunrise.ch...
I think that depends on how many units you have to construct. I have made
100's of prototype's over the past couple of years and I usually do it with
a dispenser, some solder paste (to avoid paste mask), tweezers and a mini
oven where I can easily control the temp. Its a great way to do it if you
have more than a couple of boards to build. I usually load resistors and
other passive components like this but use the "Tip with a hole" for and IC
smaller than an SOIC. I have found that using paste on SSOP packages
always ends up with bridges or dry joints and usually require a touch up
with some flux and an iron anyway. The paste/heat technique works well for
me and I once constructed 10 x PCB's with 250 parts each in about 14 hours
including the pasting........ It was a very long 14 hours.
Regards
AJ
Robin
Try the hot air gun from RS number:-
684-591
at
This was generally adopted for mass production use by a company here in
Cambridge after trying e.g. the Weller desoldering station with its
massive nitrogen bottles etc.
It is a trifle nerve wracking to begin with e.g. you can blow away the
surrounding surface components of the thing being desoldered if you use
high air speed and don't blow vertically down.
But with practice it is *fast* and *safe* e.g. using heat setting 6 and
low airspeed, we were able to desolder the *plastic" battery contacts
on an eight layer board without melting them, and then put them back
again.
We routinely removed/replaced large quad packages:-
1) Set to 7, use the half inch nozzle.
2) Hold vertically above.
3) Patiently direct the heat with slight circulating motion if the
package is large.
4) Notice the smell as the flux begins to melt, say after 30 seconds to
60 seconds. Sometimes this can take 2 minutes. If it takes say 15
seconds, the heat is too much!
5) Gently prod the package laterally to see if it is free. (Don't pull
upwards! - (yet))
6) Using same tweezers:-
(Safer-grab, risk-of-drop) grip opposite sides of package and lift
cleanly upwards (more-dangerous-grab less-risk-of-drop) grip top and
bottom of package after sliding one prong of tweezer under and lift
cleanly upwards.
7) DO NOT DROP see 10).
8) And then immediately clean the pads with the solder braid and weller
large tip no7 iron you have ready heated to hand.
9) (Easy but slow, (board can cool down)) At your leisure, and using
eye-glass, tack opposite corners of new package and use the drag-flow
method to resolder each side, wicking off the last two or three pins if
necessary.
9) (Fast: mass-production-bored-experts) Immediately flux the pads and
replace the new package using slight sideways taps to nudge it into
alignment. You skip 8) using this method and maybe slightly higher heat
setting.
The danger here is that at the moment of removal and replacement, all
the surrounding components are floating so you much *not* jog the
board!
10) When you do jog the board or knock a few out of place... just push
them back again with your tweezers. This involves the
pat-your-head-while-rubbing-your-tummy-difficulty i.e. you have to keep
the hot air vertical, correct height and rotating with one hand while
you prod the off-position component with the other.
The same company also settled for the small Weller hot air gun (not
nitrogen) for replacing individual e.g. 0805 packages without the
danger of knocking everything else out of position.
Cheers
Robin
Michael
So could you actually use a gun like this for soldering?
I don't have any desoldering to do....it sounds like you've had some success
soldering with it.
I have one like it and they get damn hot...also have some pretty small
nozzles.
So, if I use the flux John was talking about and one of these.....?
I'll try anyway on some practice boards.
I suppose tack down a couple of corners and "try" to do one side at a time?
Thanks for all the good info....I've printed it out.
"Robin" <robin...@tesco.net> wrote in message
news:1149664305.5...@h76g2000cwa.googlegroups.com...
Robin
> Robin...
>
> So could you actually use a gun like this for soldering?
>
Yes, but if you only intend to solder virgin ICs and PCBs its easier to
tack opposite corners and then use the drag-a-pool-of-solder per-side
method provided the pitch is wide enough to discourage wicking.
For very fine pitches you could slap fresh solder over all IC pins and
de-wick with solder braid - but this can be frustrating depending on
the braid-flux-corrosion-quality: Or you could use the heat gun:-
1) Rapidly coat all virgin pads with fresh solder (i.e. fresh flux)
using the drag method with a wide, Weller number 7 tip, to leave neat
domes of solder with no inter-pad wicking.
2) Place package on top of domed pads and align correctly.
3) Keeping down-draught vertical, heat the whole (with gun).
If you have too much air-flow, the IC will be blown off-alignment
immediately (i.e. no harm done) so repeat 2) and 3).
As the solder melts, the IC will settle down to the correct height.
(Some fresh liquid flux is handy here if the process takes too long and
burns the flux away). Don't rely on surface tension for final
alignment, it might or might not, try to get it right at 2). If it is
slightly out of line say 20% it should be OK if the solder is still
"fresh" and nicely flowed.
It is possible to nudge it a little for perfection but you don't want
to mess about too much because it's a hot job! Better to get 2) right
first time and keep your body on the cool side of the heat gun.
NB only use the above mentioned heat-gun, the one with the graduated
dial on back-end (was it ten heat settings? Or fourteen?) and LED heat
indicators on the barrel and, if I remember correctly, the three
position switch in the handle (or was it two?). You need a generous
air-flow and good control of both heat and flow.
If the bastard won't align at 2) re-do the domes with less solder, use
more speed and less solder. Very little is required, it only takes a
second or two for near-perfect regularity.
Evidently if you bend a leg getting it out of the packaging then it
won't sit flat so check this first.
Cheers
Robin
Robin
> Robin...
>
>
> I don't have any desoldering to do....it sounds like you've had some success
> soldering with it.
>
the fault-finders and repair.
The highly expensive desoldering stations were hardly used because they
only work properly when perfectly maintained and everything is always
done in a rush so they were either blocked and/or oxided or not
switched on (it takes time to warm up) and if they were accidently left
switched on then they oxidised or someone would get impatient and use
the tip as a crow-bar and knock the plating off it.
The heat guns were instantly hot, and vandal proof as well as
vandal-hostile to some extent.
Cheers
Rob
Rich Grise
> On Tue, 6 Jun 2006 09:11:43 -0700, "RST Engineering \(jw\)"
>
>>where we used a flux that had the appearance and consistency of water. Is
>>that the stuff you are talking about and where do you get it? What do you
>>clean it with?
>
> non-conductive, brown/amber liquid, viscosity and color about like
> maple syrup. You can dilute it a little with alcohol for the SSOP
> soldering thing, maybe.
>
> Clean with any nice solvent. We have a vapor degreaser with some
> exotic 3M stuff in it. Most hand-washing is done with isopropyl
> alcohol, although I like acetone, nasty and toxic as it is.
>
> RMA flux is great. If you have a cruddy, dull solder joint, apply a
> tiny dab and touch it with an iron, and it'll instantly get smooth and
> shiny.
>
In the USAF, we used to get that stuff in quart-size jugs. I once used it
on my hands, to make them sticky to lace a cable in an airplane, where
everything is covered with something greasy and slippery, usually
hydraulic fluid or jet fuel. Boy, it made my hands sticky, all right! Got
the job done, and just washed it off with ordinary cleanser. ;-)
PS: I like acetone as a solvent too, as long as there's no polystyrene
around. :-) Did you know that acetone is 100% miscible with water?
Cheers!
Rich
John Larkin
wrote:
Well, it mixes but it complains first. Dump a bunch of dirty acetone
in the toilet... it runs around in circles and gets all upset before
it sinks in. Fun, like kicking an ant pile.
Heat a coil of bare copper wire with a torch, red hot, then suspend it
just above the surface of some acetone. It will stay red hot.
John
Brian
OK, here is the easy way....
Any hot air gun will really work, I like the hot air stations with varying
nozzles that match the part to be soldered as they use less heat on the
part. The TRICK is to have the air nozzle in a holder so it is out of your
hands, steady, and able to move up and down over the part (like an old
inspection scope stand or a premade device).
Dress the pads with solder. Tack two pins of the part down. Add you favorite
flux. Adjust the height of the air nozzle, turn it on and adjust the air
flow. Wait for the solder to flow. Solder tension will align the part, but
you help it by gently tapping on the board. Once it is aligned, turn off the
air and pull the nozzle up with the stand.
Simple. Effective. Cheap.