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Hand-soldering SMT
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2  Next [all]
Author Hand-soldering SMT
latigid on
Okay, there are a few posts in the TTSH thread on soldering SMT components by hand. Instead of gumming up that one let's talk about it here.

Link 1
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Link 4

I'm not out to say that you're all terrible at soldering and can't handle these tiny components, it's more that evidence suggests one can damage things (like ceramic caps and inductors) by unwittingly overheating or flexing them.
meatcliff
that's true, but of course you can also damage through hole components in similar ways, burn pcb pads/traces, etc and these issues can mostly be avoided with experience.

it comes with the territory of DIY, even pro manufacturing.
Altitude909
meatcliff wrote:
that's true, but of course you can also damage through hole components in similar ways, burn pcb pads/traces, etc and these issues can mostly be avoided with experience.

it comes with the territory of DIY, even pro manufacturing.


Seriously, a thousand internet threads < a weeks worth of experience. At my day job we have been hand stuffing SMD boards for 15 years and have never seen these issues and our PCBs are exposed to the worst possible conditions you can think of (high vibration, high temp, corrosive environments). If you can solder a through hole part and cant solder a 0805 part then you should really consider a different hobby.
roglok
i'm not sure if this discussion is similar to the infamous tin whiskers associated with lead-free solder... Murata and Johanson Dielectrics seem to have taken their data from the NASA report. probably all homemade circuits would be UNACCEPTABLE if NASA Workmanship Standards were the general measure...

i don't doubt that heat can crack a cap - just wondering how likely it is to happen in real life...
bugfight
most fud about smd comes from folks that haven't tried it.
ttown23
Altitude909 wrote:
meatcliff wrote:
that's true, but of course you can also damage through hole components in similar ways, burn pcb pads/traces, etc and these issues can mostly be avoided with experience.

it comes with the territory of DIY, even pro manufacturing.


Seriously, a thousand internet threads < a weeks worth of experience. At my day job we have been hand stuffing SMD boards for 15 years and have never seen these issues and our PCBs are exposed to the worst possible conditions you can think of (high vibration, high temp, corrosive environments). If you can solder a through hole part and cant solder a 0805 part then you should really consider a different hobby.


+1. When I first started, it took less than a week to attain 'pro' quality. Granted, I was doing it for 9 hrs/day, but in about 2 days I had it down, and you can, too.
monstrinho
I actually registered for a SMD assembly class at a local tech college this semester. I wanted to learn how to do it correctly, and nothing better than being trained by professionals. So far it is a lot less scary than I thought and definitely worth the investment. I love building through-hole stuff, but I can see the writing on the wall. In the near future, most new designs will be hybrid SMD/through-hole. Eventually, there will be a phase out of through hole altogether. Better to be prepared for that eventuality.
latigid on
monstrinho, any specific advice that they gave?
monstrinho
latigid on wrote:
monstrinho, any specific advice that they gave?


Well, we're only in the third week of the semester! So far, a lot of class time has been spent on proper anti-static precautions, proper use and maintenance of the equipment and being able to visually identify what correct soldering actually looks like, what a defect looks like (for class 1, 2 and 3 assemblies) etc. Basically learning what "NASA standard" means and looks like. We did our first soldering last week, and so far my big takeaway is that the single most important thing is not to move the components while soldering (or while the solder is still setting). This seems to be the most difficult aspect of it. If I learn any other less than obvious things throughout the semester, I'll definitely post them here.
daverj
I've hand soldered thousands of 0603 resistors and caps and except for one bad reel of 120pf caps (which I threw away and replaced with a different brand) I've never had any of them crack or fail.

I did have an assistant that damaged a few SMT film caps from overheating. But that can happen with through hole parts too. I had to replace those parts, and none of the ones I soldered failed.

It's unlikely that you'll flex boards enough to crack parts that way. And once you get used to soldering them, and get a technique down that minimizes the time spent soldering, they are quick to solder and quite reliable.

My technique:

1 - Put a bump of solder onto one pad of each pair
2 - pick up part with tweezers
3 - touch iron to the bump to melt it
4 - push the part into the molten bump and remove the iron
5 - gently touch the top of the part with the tweezers and touch the solder with the iron (this makes the part sit flat on the board)
6 - go and do the same for a bunch more parts, giving the earlier ones time to cool
7 - solder the second side of each part
8 - resolder the first side of each part with fresh solder. This cleans up that joint and removes excess solder
9 - inspect the soldering
meatcliff
roglok wrote:
probably all homemade circuits would be UNACCEPTABLE if NASA Workmanship Standards were the general measure...

i don't doubt that heat can crack a cap - just wondering how likely it is to happen in real life...



(NSFW)

I'm all for trying to incorporate manufacturing practices and quality in short runs and DIY, but the obsession with NASA standards some people have for DIY electronics is absurd. It doesn't come up on Muff's much, but I've stumbled onto plenty of blogs or threads on other sites where NASA is touted as the standard. I know a handful of people who were initially put off from from attempting to build modules because of claims like that misleading them into thinking that either they couldn't do it, or that kit manufacturers weren't high quality. It just isn't necessary.

I've worked on plenty of damaged components in a production environment (1-10 failures out of ~1000 units, only on one product line of 10, due to quality issues at a specific factory and lighter weight PCBs), but never at home. PCB flex is rarely an issue on boards for SDIY, so it really comes down to heat and skill.
sduck
daverj wrote:

My technique:

1 - Put a bump of solder onto one pad of each pair
2 - pick up part with tweezers
3 - touch iron to the bump to melt it
4 - push the part into the molten bump and remove the iron
5 - gently touch the top of the part with the tweezers and touch the solder with the iron (this makes the part sit flat on the board)
6 - go and do the same for a bunch more parts, giving the earlier ones time to cool
7 - solder the second side of each part
8 - resolder the first side of each part with fresh solder. This cleans up that joint and removes excess solder
9 - inspect the soldering


I've used Dave's technique on hundreds of smt parts, and never had any problems.

Personally I don't see that much hostility towards the parts here on muffs - sure, there are a few people who are reluctant, but most people are cool with it. I was surprised that my suggestion to sub a slightly larger part caused a minor uproar - what was the big deal about that? It's just a few cents worth of parts. Maybe I'll just use the smaller part just to be cool.
mosheen
sduck wrote:


I've used Dave's technique on hundreds of smt parts, and never had any problems.

.


I do the same. It's really not hard once you get going. Just lay off of the caffeine or you'll throw parts all over the board! hihi

A fine tip and the right temperature is the key! I use this tip on my weller for 806 components: Tip
I use a normal cone tip fro drag soldering multi pin packages.
seanpark
meatcliff wrote:
I'm all for trying to incorporate manufacturing practices and quality in short runs and DIY, but the obsession with NASA standards some people have for DIY electronics is absurd. It doesn't come up on Muff's much, but I've stumbled onto plenty of blogs or threads on other sites where NASA is touted as the standard. I know a handful of people who were initially put off from from attempting to build modules because of claims like that misleading them into thinking that either they couldn't do it, or that kit manufacturers weren't high quality. It just isn't necessary.

I've worked on plenty of damaged components in a production environment (1-10 failures out of ~1000 units, only on one product line of 10, due to quality issues at a specific factory and lighter weight PCBs), but never at home. PCB flex is rarely an issue on boards for SDIY, so it really comes down to heat and skill.
"That's gonna be my next video. I'm going to burn the DVD of NASA.. and that shirt I have!." That dude is hilarious.

I think the NASA info is very useful. I don't attempt to follow every guideline but it's great to see what doing the thing as well as possible looks like.

As for surface mount, I too have used the technique described by daverj with no problems. Big surface mount parts are easier than through-hole IMO. It's easier to get good thermal transfer to the whole joint and two less holes to drill for every part.

As was said, everyone should just try it out. DON'T MAKE YOUR FIRST ATTEMPT ON YOUR TTSH BOARD THO.

Tip selection is important. I now use a 1.6mm 'screwdriver' tip (looks like a little flat head screwdriver, flat not slanted) for 90% of surface mount and through hole soldering. It's very easy to butt against an smd joint or a through hole joint for that matter.

Bought that particular tip based on daverj's post in another soldering thread. thumbs up
falafelbiels
So how does one hand-solder SMT electrolythics anyway?
mosheen
falafelbiels wrote:
So how does one hand-solder SMT electrolythics anyway?


Make sure you buy the kind with the tabs exposed or curled up on the side of the base, and make your PCB pads a little bigger. It's not bad at all. The bottom tab components are all reflow. That again isn't hard to do once you get the hang of it, but you need to invest more time and money into gear for it.
falafelbiels
mosheen

Thank you. I didn't even know there were those with exposed tabs. I just got real frustrated with them a couple of times. I might just stick with TH for these regardless if they can be fit in...

Apart from that I think I do prefer SMD over TH except maybe for projects with too many different value parts. The TH parts stock in my place is pretty vast and I do enjoy the sight of a very crowded bunch of stood up components too anyway.
I hardly have a good SMD stock. i do have several rolls of SMD resistors though, which are very, very cool to get in the mail.
L-1
A dispencer + infrared oven - and your SMDs are soldered as by a robot.


slow_riot
through hole till i die.

here's my pro soldering guide for through hole.

step 1. solder.

step 2. finish soldering.
Altitude909
mosheen wrote:
falafelbiels wrote:
So how does one hand-solder SMT electrolythics anyway?


Make sure you buy the kind with the tabs exposed or curled up on the side of the base, and make your PCB pads a little bigger. It's not bad at all. The bottom tab components are all reflow. That again isn't hard to do once you get the hang of it, but you need to invest more time and money into gear for it.


Solder paste is your friend here. Electro caps are a good example of a situation where it helps a lot. PLCC and QFN are others. With paste, you can heat the pad on the board while making contact with the part lead and that heat will suck in the solder paste for a good joint. Not so easy with wire solder where you have to feed it from the outside instead of a pool of it already there. I generally use a hot air rework gun for stuff like this since the thermal conductivity of exposed pads and solder is a 10x more than the FR4 or the component over mold so it only takes a second to flow the solder on all sides and move the part around without the risk of frying it
mosheen
Altitude909 wrote:


Solder paste is your friend here. Electro caps are a good example of a situation where it helps a lot. PLCC and QFN are others. With paste, you can heat the pad on the board while making contact with the part lead and that heat will suck in the solder paste for a good joint. Not so easy with wire solder where you have to feed it from the outside instead of a pool of it already there. I generally use a hot air rework gun for stuff like this since the thermal conductivity of exposed pads and solder is a 10x more than the FR4 or the component over mold so it only takes a second to flow the solder on all sides and move the part around without the risk of frying it


That's a good point too! I just haven't tried it yet. I guess the paste would allow you to solder the bottom tab caps very easily.
cleaninglady
I do it Ken style. Put the part in place , put your fingernail on it , solder that side. The part is now firmly in place. Now solder the other side and fix up the first solder joint if needed.

Simple. SlayerBadger! SlayerBadger! SlayerBadger!
seanpark
slow_riot wrote:
through hole till i die.

here's my pro soldering guide for through hole.

step 1. solder.

step 2. finish soldering.


You forgot drilling the holes, forming the leads, and clipping the leads hihi
adam
i've been pondering solder paste, a solder mask pen and a hot air gizmo for diy smd, on home-made unmasked boards anyway - though the only mask pens i've seen have been fine touch-up pens.

for breaking whiskers some people suggest running a knife between the tracks when solderings finished.
Altitude909
I use the chip quik pastes, you apply it with a syringe so you really dont need a stencil. It's a bit of a learning curve of how much you need to apply but once you figure it out, its easy
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