stereo microscope to do SMT?

[[email protected]]

Do I need a "stereo microscope" to do SMT? Or will a good lighted
magnifing lens do it for an occasional MSOP-8 install? If a
microscope will one of those "school lab" $75.00 ones work? Thanks All
for your time. Wayne

 

[Smitty Two]

Do I need a "stereo microscope" to do SMT? Or will a good lighted
magnifing lens do it for an occasional MSOP-8 install? If a
microscope will one of those "school lab" $75.00 ones work? Thanks All
for your time. Wayne

This is a question for your optometrist and the answer is almost
certainly age-dependent. What I could see clearly with naked eye twenty
years ago, I now need a pair of strong reading glasses coupled with the
good lighted magnifying lens to see. Nowadays, I use a high quality
stereo zoom microscope to pull splinters out of my finger, let alone
solder SMT.

If you can't tell whether the solder has flowed to form a backside
fillet (from inner edge of leg to pad) then you need to crank up the
magnification. Because SMT is designed for automated soldering, the pads
are often scarcely larger than the component leg, and it's easy to pile
solder on top of the leg without making a good connection to the board.

 

[Arfa Daily]

This is a question for your optometrist and the answer is almost
certainly age-dependent. What I could see clearly with naked eye twenty
years ago, I now need a pair of strong reading glasses coupled with the
good lighted magnifying lens to see. Nowadays, I use a high quality
stereo zoom microscope to pull splinters out of my finger, let alone
solder SMT.

If you can't tell whether the solder has flowed to form a backside
fillet (from inner edge of leg to pad) then you need to crank up the
magnification. Because SMT is designed for automated soldering, the pads
are often scarcely larger than the component leg, and it's easy to pile
solder on top of the leg without making a good connection to the board.

There are stereo long-reach microscopes available for very reasonable prices
nowadays, but perhaps not as cheap as $75. I paid about 5 times that for
mine, but it has paid for itself many times over. I agree with everything
that Smitty said on the subject. I suppose I would have to add that it
depends on what your line of useage is going to be. If you are a hobbyist
just doing the occasional bit of sm work on home projects, then a good light
and a good quality headband magnifier ( I use one of those as well ) or a
jewellers loupe might be all that you need. If you are going to be working
with the stuff commercially, on a daily or even weekly basis, then I would
recommend a decent self illuminating microscope, as a worth-every-penny
addition to your workshop equipment.

Arfa

 

[GregS]

Do I need a "stereo microscope" to do SMT? Or will a good lighted
magnifing lens do it for an occasional MSOP-8 install? If a
microscope will one of those "school lab" $75.00 ones work? Thanks All
for your time. Wayne

I don't think you need a microscope, but i certainly use magnifiers,
The scope is good for inspecting very closly.
A cheap microscope is around $300

greg

 

[[email protected]]

There are stereo long-reach microscopes available for very reasonable prices
nowadays, but perhaps not as cheap as $75. I paid about 5 times that for
mine, but it has paid for itself many times over. I agree with everything
that Smitty said on the subject. I suppose I would have to add that it
depends on what your line of useage is going to be. If you are a hobbyist
just doing the occasional bit of sm work on home projects, then a good light
and a good quality headband magnifier ( I use one of those as well ) or a
jewellers loupe might be all that you need. If you are going to be working
with the stuff commercially, on a daily or even weekly basis, then I would
recommend a decent self illuminating microscope, as a worth-every-penny
addition to your workshop equipment.

Arfa

Cool, Well I guess I'll give the mag glasses a shot and see if i have
any problems then spring for a good video mag or stereo scope I
hear two sides on those two items also but time will tell. Thanks much
for info!!! Wayne

 

[[email protected]]

There are stereo long-reach microscopes available for very reasonable prices
nowadays, but perhaps not as cheap as $75. I paid about 5 times that for
mine, but it has paid for itself many times over. I agree with everything
that Smitty said on the subject. I suppose I would have to add that it
depends on what your line of useage is going to be. If you are a hobbyist
just doing the occasional bit of sm work on home projects, then a good light
and a good quality headband magnifier ( I use one of those as well ) or a
jewellers loupe might be all that you need. If you are going to be working
with the stuff commercially, on a daily or even weekly basis, then I would
recommend a decent self illuminating microscope, as a worth-every-penny
addition to your workshop equipment.

Arfa- Hide quoted text -

- Show quoted text -

Also Does one "tin" the board first before plopping the dinky little
MSOP-8 chip on it? Suck the solder off with wick? and what kind of
rosin besides what is in the solder is best? Thanks again for your
time Sir's ! Wayne

 

[GregS]

Also Does one "tin" the board first before plopping the dinky little
MSOP-8 chip on it? Suck the solder off with wick? and what kind of
rosin besides what is in the solder is best? Thanks again for your
time Sir's ! Wayne

Definately tin the board.. I mostly use a very thin solder of 63/37 leaded
solder.

greg

 

[Arfa Daily]

Definately tin the board.. I mostly use a very thin solder of 63/37 leaded
solder.

greg

I always tin the board first, then wick the excess back off until the pads
are really smooth. I then 'tack' one end or one pin of the device to the
board using just heat from the iron and the tinning on the component pin and
pad. I then examine the positioning really closely with the magnification.
If I am happy that the component is located exactly correctly, I will hold
it in place with the tip of a scalpel, and tack solder another pin and then
re-examine the positioning. If all is still well, then I go ahead and solder
it in fully.

A liquid flux is absolutely essential for the soldering process as it
assists the solder to flow by capilliary action between the pins and pads
much more readily, which helps really significantly with not getting
inter-pin shorts with fine pin-pitch sm components. Very fine gauge 'angel
hair' solder is also a must. The flux that I use comes in an aerosol can,
and is made by Electrolube and is their product SMFL 200. It is very cheap,
and very very effective.

Of course, all this assumes that you are talking 'conventional' hand
soldering. The best way is to use paste solder and hot air, but I don't
think that you are talking that level of professional at this point ?? It is
all down to practice and confidence to get good results, and is really not
that difficult if you use a fine tipped iron with enough heat, and are
reasonably skilled at normal size soldering. If you do get shorts between IC
pins, don't worry about them at the time. Just note where they are, and
carry on. Go back to them at the end with a good quality wick placed against
the vertical face of the pin, and reheat. the excess solder will readily
come out from between the pins, without compromising the joint. Before your
final examination under magnification, clean up with a flux remover. For
this I use a Servisol aerosol product. You will be amazed at how good a job
you can do with a little practice.

Arfa

 

[[email protected]]

I always tin the board first, then wick the excess back off until the pads
are really smooth. I then 'tack' one end or one pin of the device to the
board using just heat from the iron and the tinning on the component pin and
pad. I then examine the positioning really closely with the magnification.
If I am happy that the component is located exactly correctly, I will hold
it in place with the tip of a scalpel, and tack solder another pin and then
re-examine the positioning. If all is still well, then I go ahead and solder
it in fully.

A liquid flux is absolutely essential for the soldering process as it
assists the solder to flow by capilliary action between the pins and pads
much more readily, which helps really significantly with not getting
inter-pin shorts with fine pin-pitch sm components. Very fine gauge 'angel
hair' solder is also a must. The flux that I use comes in an aerosol can,
and is made by Electrolube and is their product SMFL 200. It is very cheap,
and very very effective.

Of course, all this assumes that you are talking 'conventional' hand
soldering. The best way is to use paste solder and hot air, but I don't
think that you are talking that level of professional at this point ?? It is
all down to practice and confidence to get good results, and is really not

that difficult if you use a fine tipped iron with enough heat, and are
reasonably skilled at normal size soldering. If you do get shorts between IC
pins, don't worry about them at the time. Just note where they are, and
carry on. Go back to them at the end with a good quality wick placed against
the vertical face of the pin, and reheat. the excess solder will readily
come out from between the pins, without compromising the joint. Before your
final examination under magnification, clean up with a flux remover. For
this I use a Servisol aerosol product. You will be amazed at how good a job
you can do with a little practice.

Arfa- Hide quoted text -

- Show quoted text -

Well, even though I didn't spend as much as I should have (125.00) on
it I have a hot air station on the way. I've always hated touching
something that is electric against such sensitive stuff. Don't even
know the brand but the several reviews on it said it was good for the
money and for the small numbers of SMT's I'll be doing

 

[Smitty Two]

Well, even though I didn't spend as much as I should have (125.00) on
it I have a hot air station on the way. I've always hated touching
something that is electric against such sensitive stuff. Don't even
know the brand but the several reviews on it said it was good for the
money and for the small numbers of SMT's I'll be doing

Keep us posted on how that works out. How will you be applying the
solder paste?

As far as electricity, it comes from the wall and also out of thin air.
I guess most soldering irons have grounded tips, but of course for
working on live circuits it's essential to break the damn ground plug
off the power cord.

As for the other stuff, I'm not too much of a believer in the ESD
goblin, but it's rumored that some types of chips are sensitive, so you
might want to take some small precaution there, too.

 

[[email protected]]

I have spray flux. I'll keep you'all posted as soom as the board gets
finished and I get time to put it together. Might be a little time.
Thanks much all!

 

[[email protected]]

This is a question for your optometrist and the answer is almost
certainly age-dependent. What I could see clearly with naked eye twenty
years ago, I now need a pair of strong reading glasses coupled with the
good lighted magnifying lens to see. Nowadays, I use a high quality
stereo zoom microscope to pull splinters out of my finger, let alone
solder SMT.

If you can't tell whether the solder has flowed to form a backside
fillet (from inner edge of leg to pad) then you need to crank up the
magnification. Because SMT is designed for automatedsoldering, the pads
are often scarcely larger than the component leg, and it's easy to pile
solder on top of the leg without making a good connection to the board.

I could not imagine doing the repair without a zoom stereo
microscope. The problem with the lab type scopes is that you will not
get the working distance needed to get tools under to manipulate nad
solder the part. A maginifying glass setup may work or if you are
really young and your eyes are really good you may can pull it off but
it would be hit or miss at best.

http://www.circuittechnology.com

 

[doug]

I could not imagine doing the repair without a zoom stereo
microscope. The problem with the lab type scopes is that you will not
get the working distance needed to get tools under to manipulate nad
solder the part. A maginifying glass setup may work or if you are
really young and your eyes are really good you may can pull it off but
it would be hit or miss at best.

http://www.circuittechnology.com

I use an American Optical stereo zoom with a .5x accessory lens. This
has two advantages. One, the working distance increases to about 7
inches and two, the minimum magnification drops to 3.5x which is nice
for viewing larger areas. By the way, do not try this with 5x eyepieces
instead of the standard 10x as the tube size is such that you only get
the central part of the image. The .5x AO575 lens shows up occasionally
on ebay but they are not cheap.

 

[mc]

Anyone want to recommend a specific stereo microscope for this kind of work?

The eyepieces must work well for an eyeglass wearer.

 

[Sergey Kubushin]

Anyone want to recommend a specific stereo microscope for this kind of work?

The eyepieces must work well for an eyeglass wearer.

I have Madell on my bench at work and at home. Quite happy with them--didn't
cost arm and leg and very nice to work with. I used to use various lenses
before biting a bullet and buying a microscope. Now I can't even imagine how
I could live without one...

One suggestion--if buying Madell (they are selling them on eBay too,) go for
dual-bar boom stand.

 

[mc]

I have Madell on my bench at work and at home. Quite happy with

them--didn't
cost arm and leg and very nice to work with. I used to use various lenses
before biting a bullet and buying a microscope. Now I can't even imagine
how
I could live without one...

One suggestion--if buying Madell (they are selling them on eBay too,) go
for
dual-bar boom stand.

Do you wear glasses? How is the eye relief -- do you have to put your eyes
very close to the eyepieces?

 

[Michael A. Terrell]

Do you wear glasses? How is the eye relief -- do you have to put your eyes
very close to the eyepieces?

I always took my glasses off. It caused less eye strain, and the
rubber eye cups could be cleaned with Isopropyl Alcohol to remove the
body oil and bacteria.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Sergey Kubushin]

I always took my glasses off. It caused less eye strain, and the
rubber eye cups could be cleaned with Isopropyl Alcohol to remove the
body oil and bacteria.

I do wear glasses but I'm nearsighted so I always take them off when doing a
delicate work. But yes, it works fine with glasses on.

 

[Dan]

Do you wear glasses? How is the eye relief -- do you have to put your
eyes very close to the eyepieces?

A number of years ago I looked into cheap stereo microscopes for working on
60's vintage Accutron wristwatches & other watch work & seriously consider
these Russian ones http://www.microscopes.com/ms-la-mi-sf.html Never got
one so I don't know about the eyeglass aspect.

Dan