MLCC cap soldering

Hi all,
I recently shared a circuit on french topic subboard to get comments. On my PCB I plan to used MLCC 1206 capacitor and one person stated it's not recommended to solder these component with an iron and better to use an oven.
Just one guy stated this and no more comment about this. It could be a showstopper to me (since I do not have this equipment and do not plan to get one)

Does anybody have an experience about this ?

Thanks in advance

I never had a problem even with 0603. That said, there are hot air rework station for less than 40€. I do find them quite convenient to place just a few SMD components.

I warm the board a little first, then carefully apply some solder paste to the pads from a syringe (it will stick to a warm board easier). Then I reflow with the hot air gun.
Of course, this goes nowhere near the recommended temperature curve, but I never had problems.

See the datasheet for a typical 1uF, 16V rated cap

Page 13 discusses soldering.
The concern with hand soldering is that you can introduce thermal stress across an unevenly heated part and could end up cracking it.

If you're doing surface mount work, you should look into getting a hot air rework station, then you can blow hot air across the part and keep it at the same temperature as the solder melts. A small syringe of solder paste with a needle tip dispenser will last you a while.

1206 is easy to hand solder. 0805, 0603, get harder. Its tedious to hand solder lots of SMDs, definitely
nicer with an oven, very high quality results are obtained and so long as you don't use too much solder paste
little risk of issues.

Its not hard to convert a cheap toaster oven - I got one from ALDI and moved the bottom element to
the top.

Thx but the point was more about capacitor technology that may not support iron rather than component size.
I bought a trial smd solder board and get no major issues...

Ceramic components are pretty indestructible through heat, they are made by sintering at much much higher temperatures than a soldering iron!

The physically larger, multi layer ceramic caps are more susceptible tho as you can get a large temperature gradient across the part.

BTW, some of those cheap rework stations are trying to kill you. Google for the caveats and check the one you get accordingly. Mine for <40€ from German Amazon was fine, though.

Even the good hot-air rework stations have bare mains heater elements in the nozzle/snout, I would
always recommending checking earth continuity between the nozzle and earth pin on the plug.

I have never had problems soldering MLCC caps (mostly 1206, some 805) by hand - I've put down 100-200 in the past year or so by hand. It's annoying, and I usually reflow solder smd caps (modified toaster oven - ControLeo2 from kit), but I haven't had problems with damaging the caps.

Using temp controlled iron @ 700 degrees.

To spare other the search: That is about 370°C for the rest of the world, or a seriously hot iron :slight_smile:

I have 'never' had problems soldering SMD components by hand, including component reliability afterwards.

Agree with getting a rework station, when you are going to do this regularly.

Never used a toaster for this, but it makes sense if you are doing production runs.

Recommend you make a stand, to hold a hot air wand, if you want to keep hands free.

.

Interesting idea. On the other hand, I try to control temperature with distance to mimic the preheat phase of a reflow oven a little bit.

I adjust temperature to to ~250'C, heat the board, then raise the temp to ~350-390.

.

LarryD:
I adjust temperature to to ~250'C, heat the board, then raise the temp to ~350-390.

Wow.
I set my rework station temp to 265C, and leave it there.
Heat the surrounding area for a minute or so, and then heat the part/pins.
Leo..

I don't think temperatures are really comparable. I set mine to 300, but go much closer in the end. Also, the amount of air controls heat transport.

Yes, several things to take into account:

  • Temperature
  • Air speed
  • Nozzel size.
  • Distance from work
  • Type of solder
  • Mass of component.

I use a high intensity (15,000-30,000 Lux) light to monitor the melting solder for completion feedback.

.

Whew, I'm surprised that much light doesn't melt the solder by itself :wink: