0603 caps' caps

It sounds like you're using too much solder or too much heat. Breaking just from soldering shouldn't happen. Use the minimum possible amount of solder, and solder it quickly.

Good Luck! Rich

Are you using un-leaded solder ?

Michael Kellett

Some soldering irons reach insane temps.

But I agree, a surfmount cap with one soldered to copperclad, and the other end sticking up, is very easily damaged.

John

I used one like this to bypass a divider/reference voltage and got quite large errors from the wire moving. It was creating a strain on the capacitor body, and I guess modulating the value.

I am using conventional leaded solder (0.3mm diameter). The iron is decent, suitable for SMD work, with temperature regulation and so on...

Should I expect different behavior with _un_leaded solder?

Pere

As ii pointed out in the original post, I have had _several_ problems related to capacitors "breaking". On some prototypes I even had to reinforce a PCB (0.8mm, though) with some perpendicular PCB strips to avoid the board flexing and ruining capacitors. This has also happened on small 1.6mm PCBs.

I did not note if this was related to the soldering iron temperature. It is true that I sometimes regulate the temperature higher than the minimum (up to 330 C) to enhance speed but, then, the process is quick. But perhaps not so quick as to avoid the small thing to become overheated...

I have just searched for some information and found this

"Manual soldering with a soldering iron is to be avoided, hot-air methods are recommended for making repairs."

So, at which temperature do you regulate your iron when soldering these?

Pere

suitable for SMD work, with temperature regulation and

If you have enough space, use 2.5mm pitch ceramic caps instead of smd. Soldering one end of smd dead bug style means it will break at minimal tension. Use smd only where you know there won't be any tension. Not on connecting wires, for example.

I have never actually had any problems when manually soldering capacitors to actual circuit boards. Things can start to come apart if you remove again them incorrectly, or if you are not using a proper PCB. But I would guess lower temperatures and minimal solder would be good. I usually use 0805, so that may be a difference too.

Use a 600 degree tip instead of a 700. Perform the solder operation within a 2 second window. Refrain from reflowing the solder joint whenever possible.

If you must use the actual smd part to get reliable data for operation, you can glue it to an insulator, like a silica transistor heat sink or a small piece of PCB material, and solder the wires from it to the other circuit parts. If a standard dipped ceramic cap of equiv. value could be used to characterize the design, it would be a lot easier on you.

It isn't the solder cooling that causes the problem, per se. The solder process itself almost detaches the terminations on SMD chip capacitors, so it is the heat in-flow during hand soldering that does the most damage, hence the cooler tip temp suggestion.

This is why SMD reflow ovens bring up the assembly temp on a gradual ramp, then reflow, then ramp down steeper, but not as fast as ambient air would.

You can reduce the issues if you pre-heat the assembly to a couple hundred degrees F before soldering as well. It is hardier to solder hot parts though, however, less damaging to caps.

I used to glue a whole bunch of SMD parts

Lead free solders are usually a hotter process, so more damage to a cap would occur.

Just one question: Does the failing caps seem to be batch related?