First time soldering a SMD, tips/tricks?

[Colt45]

Yeah... Tack one corner, then the other, then flow all the other pins... if you got too much on a pin, wick it off and try again.

Tip size doesn't really matter much for ICs IME... I've put ones like this on with a 1/8" chisel... I actually prefer it to the tinyass tips...

 

[Modelworks]

Originally posted by: chorb
I just got to see a BGA rework station in action today, crazy bit of machinery.

BGA is a nightmarish thing.
I saw one DSP chip that had 1500 connections on the bottom .

 

[MrDudeMan]

Originally posted by: Modelworks

Originally posted by: MrDudeMan
o.

P.S. Your advice was bad because using glue can and will effect certain circuits. Offering that as general advice is piss poor at best, and I'd think someone with "decades" of experience would know that.

Your idea that a person soldering a opamp is going to effect the circuit because he uses glue, is hilarious. Or that heating the pins for longer than an instant will destroy it is funny as well.
These parts can take 200C for over 20 seconds before any damage begins to happen.
Look up reflow oven and the temps involved.

I've seen many an engineer that can quote from the books and then starts scratching their head when the real world doesn't do it that way.

It is because you might have to sterilize a room when you are a doctor doing an operation , that doesn't mean you need to when you are placing a bandaid on a cut.

As for areas I worked in, it was prototyping on things like interconnects on supercomputers running at gigabit speeds long before half the world even knew of the term.

The guy is building a small portable amp, not the next GPS system for missile defense.
I suppose you would have him purchase a hot air station as well ?

Yeah you're right. Teaching someone bad habits is a great idea.

Your idea that a person soldering a opamp is going to effect the circuit because he uses glue, is hilarious.

This is definitely hilarious, except for the fact that I've seen it with my own eyes. I noticed you still have no answers other than sarcastic responses.

Or that heating the pins for longer than an instant will destroy it is funny as well.
These parts can take 200C for over 20 seconds before any damage begins to happen.
Look up reflow oven and the temps involved.

You're right again. This is exactly what I said. Oh wait, no it isn't...

You don't have to be super paranoid, but keep in mind that almost everything you will solder in the surface mount world can and will break with too much heat for too long.

which is exactly right. I never said an instant, but you are wrong anyway. Most datasheets spec 260C+ but the amount of heat produced is different than the temperature. Heat is what causes most of the damage. Heat is not the same as temperature. Again, you have no facts, but I've actually seen performance differences in a 20MHz micro-controller because of how it was soldered. The internal RC oscillator lost it's calibration and the A/D gain changed.

I've seen many an engineer that can quote from the books and then starts scratching their head when the real world doesn't do it that way.

You are essentially proving my point. Teaching bad techniques is what causes this as well as inexperience. I'm not quoting from a book, but you can keep calling me a dumbass all you want.

As for areas I worked in, it was prototyping on things like interconnects on supercomputers running at gigabit speeds long before half the world even knew of the term.

I didn't ask nor do I care and it's not even relevant to the conversation as I said earlier. We are talking about soldering and it doesn't take a rocket scientist to figure it out. Also, I work on core design doing the same stuff you used to do and I don't see at all how that furthers your argument, nor does it give you any credibility.

The guy is building a small portable amp, not the next GPS system for missile defense.
I suppose you would have him purchase a hot air station as well ?

Chances are it will be fine even if he makes some mistakes, but there's no harm in telling someone the right way to do things and explaining the theory. I suppose you could come up with some more bullshit responses so we'll wait and see what you come up with next. At first I was just offering some advice, but now it's amusing because you thought you were going to just call me out on being a high school kid. I've been doing this long enough to have an opinion whether you like it or not, and I've actually seen what I am describing happen in relatively low speed parts (like DIY amplifiers such as in the OP) as well as high speed parts.

 

[CallMeJoe]

Disclaimer: I am not an engineer. I am merely a working avionics technician, trained in high reliability soldering by the USAF in 1974 then trained in SMD soldering by a major avionics manufacturer in 1994, with periodic refresher courses. I have successfully replaced SMD components of a variety of lead pitches and sizes, ranging from microprocessors to chip resistors approximately 1mm in length.

The technique we were taught is not too far off Modelworks' version; apply a tiny drop of liquid flux to a corner pad, hold the component in place with tweezers, then touch the junction of the PCB pad and component lead with a soldering iron tip very lightly wetted with solder. The flux will wet the solder to the pad and lead, giving you a very light solder joint. Allow the joint to cool briefly before releasing the component, then solder the remaining leads one at a time starting at the opposite end of a multi-lead component and skipping around between leads so that you do not concentrate your heat on any one section of the device. Be careful not to twist your component before releasing it. It is possible to pull a freshly heated SMD contact right off the board, since there is no plated-through hole to hold it to the board.

So far as your selection of solder, I always like a fine (.015) solder for SMD. We were also advised that silver-bearing solder was preferred for SMD.

FWIW, Machine SMD assembly for avionics gear uses tiny adhesive pads on the underside of components to secure them to the PC board. A "no-clean" solder paste is applied to the PCB pads, then the board assembly is heated to flow the solder. I've never seen cyanoacrylate recommended as a mounting agent, not because of phantom capacitance, but because the component may someday require removal.

 

[LTC8K6]

"A very small tip makes it harder, not easier."

Not for me it didn't. I was asked for advice, I gave it. The small tip was way easier for me.

Tin the pads, tin the leads, hold the item down, and quickly heat each foot individually with the tiny tip.

Worked perfectly.

I have a lot of experience, though.

 

[aphex]

So the SMD is on there, i think. How can I test if its seated properly without any cold joints before I move on?

 

[PottedMeat]

Originally posted by: aphex
So the SMD is on there, i think. How can I test if its seated properly without any cold joints before I move on?

Is everything shiny and not dull? Got a magnifying glass? Just look for cracks. Shiny and continuous flow of solder = good.

 

[Modelworks]

Originally posted by: MrDudeMan

I've seen many an engineer that can quote from the books and then starts scratching their head when the real world doesn't do it that way.

You are essentially proving my point. Teaching bad techniques is what causes this as well as inexperience. I'm not quoting from a book, but you can keep calling me a dumbass all you want.

And you just proved mine. The point I was making went right over your head.