SMD Soldiering

[kevinmcc]

For those considering adding filters, here is a good guide to SMD soldiering.

https://www.youtube.com/watch?v=hoLf8gvvXXU

[allsorts]

Easy with big 20 pin chips and bare board. Not so easy with tiny (5 mm square?) 8 pin ones on a populated board. B-)

Putting that video with my limited experience of hand soldering SMD you do need the fine solder and flux pen. Tacking down just a single corner is good but positioning the tiny filter chips with a finger is really tricky and easily painfull, bit of clear sticky tape works much better. Good eyesight, lots of light and a good magnifier are also useful. I doubt many have access to stereoscopic digital microscopes...

Oh and thanks (I think?) for reminding me I've wanted to build a nixie tube clock since the 1970's...

[Mike6158]

I finally threw in the towel and bought a nice microscope, hot air, and a very fine tipped soldering iron and set up an SMD station.

I wrote a A Beginners Guide to Soldering Surface Mount Components post for the EEVBlog. I'll see if I can reconstruct it here:

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I'm a beginner and this is my guide  

When I was in my 40's I decided that SMD's were the spawn of satan and they would never catch on  Now approaching 59... that's a long way from 60 just so you know... I have decided to start using surface mount devices. It makes perfect sense really. Now that 15+ years have gone by, I can't see worth a damn and my hands shake more than they used to (but not much). I normally work on things with tubes in them but I have an OtherMill Pro and dabble in making my own boards every now and then. I use the mill to make a prototype and then order from Osh Park if I want commercial boards (like for friends or gifts). When it comes to ordering boards, size matters  

This isn't the first project but it's a good for illustrating my list of things that a beginner should know about soldering surface mount devices. It's a double sided board with a bunch of 2200 ohm resistors on both sides. There's also a diode and cap for rf detection. Apparently they screwed up the board somehow and the surface mount cap location is not usable.




[img] http://wildlightimagingstudio.com/img/s3...4217-5.jpg[/img]

In no certain order these are the things that I know about soldering SMD's.

Opinions
(1) if someone tells you that you don't need a microscope to solder SMD's, poke their eyes out with a sharp stick and take their microscope (not really but that's bullshit)
(2) use the correct soldering iron and tip. A 1/4" chisel tip might work fine on that old 1948 Zenith AM radio but it's not going to cut it for SMD work
(3) make no mistake, SMD's ARE the spawn of satan. Especially if they are smaller than 0805
(4) it's best if you know at least one or two expletives.
(5) Do Not Yell Expletives at the Board While Looking Thru The Microscope. Your components will flit off into whatever dimension those little bastards come from
(6) Concerning item 5. Add Sneezing, Coughing, or in some cases, Breathing to the list of things that shouldn't be done

Laws of Physics
Law 1: If your project requires x components, buy at least two more than x. SMD's can occupy other dimensions, so if you drop one, it's gone, forever.
Law 2: If you place a component on the board you will need to either turn it or flip it or both
Law 3: If you drop a component and it stays in this dimension (lands on the bench) it will be upside down. Especially if it's a resistor or capacitor. They are top heavy
Law 4: When you solder a resistor or capacitor to a board, make sure you either solder them all such that the numbers are the opposite of the silkscreen or solder just one the wrong way around. This will drive some people batty and it can be a source of amusement
Law 5: Make up some bullshit like Law 4 to try to cover up the fact that you soldered 1/2 the resistors on your board opposite of the silkscreen
Law 6: If a kit manufacturer supplies 2 extra components you will, at a minimum, lose 2 components
Law 7: The first component that you pick up with tweezers will make a click sound and disappear never to be seen again. Proof they come from another dimension
Law 8: Resting the barrel of the soldering iron on your finger to stabilize it will result in some level of chaos and pain. Don't do that
Law 9: Once you get into a rhythm don't take a break. If you stop in the middle of a project you will come back with the coordination of a spastic ape and fling components off into the other dimension (where satan stores them), tombstone parts, and generally turn your nearly complete board into an ugly mess.
Law 10: If tweezers were the size of a small rocket we could use them to launch spacecraft on intergalactic missions. They apparently contain some form of warp drive

Feel free to add any helpful advice that you see fit. Laws can be added at will. They are like speed limits, nobody follows them.

Endeavor to persevere



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Or if you prefer to read the witty followup comments: http://www.eevblog.com/forum/beginners/a...msg1159261

[briangrimm]

I finally threw in the towel and bought a nice microscope, hot air, and a very fine tipped soldering iron and set up an SMD station.

I wrote a A Beginners Guide to Soldering Surface Mount Components post for the EEVBlog. I'll see if I can reconstruct it here:

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Thank you Mike.  This covers my experience with SMDs completely.  I just had to solder some 0805s for another project, and I'm getting ready to look for that microscope.  Reading glasses and a lighted magnifier weren't enough.

[cutty]

https://www.amazon.com/gp/product/B017RS...UTF8&psc=1

...and a 30 watter point will work great.

[Mike6158]

I've used paste with mixed results. Allegedly it doesn't keep well. I think mine is still good after a year in the refrigerator, maybe. That's what all the SMD soldering experts say, at least those that I've read from or watched on YouTube anyway.

I have more tombstoning with paste than if just tack a pair of corners, slather the pins in flux, and drag solder (don't like drag soldering). I've used paste and an oven made for SMD soldering. Too tedious for my liking.

I like my microscope. I can solder an 0201 component if I have to (if it makes it to the board). I use .4mm solder (.015") and that looks huge under the microscope. I use a very, very fine tip (T-30-1 Hakko), 0.1mm, and that looks huge under the microscope. To give you an idea about the size of an 0201 part - a resistor is 0.3mm wide x 0.6mm long (.012" x .024"). I don't like to solder components that small.