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I wondered what DIY folks are using to solder such parts (details of soldering station, iron/tip, magnifiers, etc.) as well as techniques that worked well for you.
Follow Ups:
The last company I worked for did a lot of automated SMT onto flex substrates...they used a conductive epoxy paste to glue components to the board. The epoxy was squeegied onto the board using a stencil. Not easy for a DIY project, unfortunately....but fun to watch.
41Hz, which (as you may be aware) makes amplifier kits based on Tripath chips, has a lot of surface mount related resources that can be accessed through their forum. Please note, as I write this they are in the middle of transitioning over to a new website scheme, so I'm not sure how much longer this information will remain available, but for now it's worth checking out. I dare say that if you go through the threads in the subforum linked below, you will be in a good position to "get the job done."
http://old.41hz.com/Forums/forum.asp?FORUM_ID=8
-- Chris
A flux pen is your friend.
I use a technique somewhat like like Adams: solder to one pad and remelt this to place the part. For multi-lead ICs you may need to solder a second pad (preferably diagonally opposite). Check that the part is correctly placed and sitting on the pads.
Then apply flux liberally to all the unsoldered joints.
Now apply solder TO THE IRON and wipe it across the unsoldered joints. Much sizzling of flux, much soldering of joints.
Mark Kelly
applied with the brush. Yup, this is important, almost makes it stupidly easy compared to without. Hard to get used to for those soldering for decades without, using the flux already in the solder. Solder wants to "stick" by its nature, you just have to help it a bit when the metal elements are so small.
And a steady hand.
Loupe or scope for checking your work. Solder using the scope if you're not drinking...
a friend who tinkers with radios and cell phones and computers uses heat gun.
Gentlemen,
I'm grateful for your posts; sharing your insights and experience - this was very interesting and helpful to me. Just what I needed!
Francois
I really love my Metcal solder station, but it was some money to be sure. They heat up and are ready to solder in about 5 seconds which is good since I'm not patient. They have some pretty cool tips and tweezers etc for doing IC's, passives, whatever. One downside (or upside depending on your take) is the tips determine solder temp.
I have been doing mostly 0402's for the last 8 years or so and will say that to go there a nice stereoscope will bring you out of the stone age. Welll that and laot's of practice. One point of note: I was sure lusting after my buddies new $150 USB camera which zooms much closer than needed for doing 0402. Nice clean image too. I think having my face pulled back from a scope and looking at a monitor instead could be an advantage. I just wish I could remember now what model etc.
Here's a good video on the topic....
Neat video. Two things I do that wasn't on the flics: 1.) Clean the surface to be soldered well with isopropanol first. There's usually a coating of some type which interferes with the flow. 2.) Use a heat sink on any component which is heat sensitive. Tiny alligator clips work well.
I've been doing manual SMD work for about 20 years now. It's really not a lot harder to do than using wire, you just need to practice a little finesse.
My secret? An eye loupe! I use a 10 power one. I have terrible depth perception,as I have one farsighted eye and one nearsighted eye. With the eye loupe, I can see the solder joints the size of Texas, and it's REAL obvious whether you've got the component where you want it and whether you are making a good solder joint. The only thing better than the loupe is a microscope with a color camera and a good monitor, but that will set you back a grand or more.
Beyond that, use a good temp controlled iron with a reasonably small tip, NOT the smallest one you can buy, it will last you an hour before the tiny tip burns off!!, and keep your temperature down. I find that installing components, I'm generally at around 800 degrees on my Hakko 926. And you need a good pair of needle tip tweezers.
You have to find your own limits though. Mine are 0402 R's and C's, and leadless parts. I just can't handle them; I have an assembler friend who I pay $25 to do the really nasty little buggers for me.
So here's how I do the typical 2-lead chip resistor or cap: tin one board pad ONLY. The other pad should be flat and clean. Grab the part gently with the tweezers ( no death grip, or the part is going to shoot across the room, and you never see it again) and place it over the pads. Reheat the solder, and position the part. Now do the second pad, and use the solder SPARINGLY.
If you look at your work after you have both pads soldered, and you made a mess or blob or cold solder joint, use fine solder wick to clean it up. Turn your iron up to 850 or so, and use the iron to heat the joint through the wick. Be quick, and just take off a little of the solder til you get the hang of it. If you dwell too long, the heat will get conducted to the other end of the part, melt the solder joint and the part will come off on the wick. It may take a few tries, but once you get used to the principle it's easy.
Those are the basics. It's just a matter of practice from here on.
Oh, and I do recommend Chip Quik for removing parts. DigiKey carries it. It stays melted down to 100C or so, so you can blob it on all the leads of a quad 44 pin package, for instance, and it will stay molten all around the part so you can just lift the part off the board. Very cool.
Have fun!
Adam912.Out.
I'll only add that some many-pinned very small SMD ICs will be destroyed by heat through solder wick sufficient to reabsorb bleed-over between pins. It takes longer, but when soldering down such tiny ICs, I prefer first to tin each pad, position the replacement chip, and then press down each pin with the thinnest needle tip available. It requires an almost imperceptible amount of solder on the tinned pads. If the IC is really small, it may be helpful to fix its position with a dab of Goop cement.
In a non-production environment, I remove the dead chip pin-by-pin by heating the pin with the needle iron and bending it back with the tip of an Exacto knife. Overheating the pad risks lifting it from PCB. Under no circumstances try prying pins with the needle tip. This will surely destroy a pad.
Don't even think about it without high magnification and good light, and save the Scotch for power-up.
If soldering pin-by-pin, Antex C/3U 15W mini-iron with 8-G .012" gold needle tip. (Buy several spare tips, as they go quickly.) Radio Shack .015" silver bearing solder. Staples has a decent $50 magnifier lamp that clamps and swivels, but I have not yet found an inexpensive magnifier lamp that doesn't eventually break.
Cool Dave, yes, I forgot about the Antex iron. It's low enough wattage that it's hard to damage parts. We had a whole production line of folks using the Antex irons when we started Applied Laser Systems 20 years ago. The assemblers loved using them.
cheers
Adam
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