Brittle Fracture Ceramic Capacitors

Lately we tend to panelize smallish boards. We generally route between the boards and leave little web thingies to hold them together.

Some people here have suggested that v-scoring would allow more boards per panel. Sounds like snapping apart scored, stuffed boards could be a stress hazard to caps.

This thing slices scored boards apart, less stress than manual snapping.

We don't seem to have problems with cracking ceramic caps. I wonder if some sizes are worse than others.

Most of our caps are bypasses, so if they open, we usually wouldn't notice. We would notice shorts.

Are you having troubles with cracked caps?

We don't use surface-mount film caps. They are really bad.

Digikey will save you time by selling pre-cracked caps:

Gotta go: donuts are calling.

Sorry

-all-

/solu

IAOMa

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aka "mouse bites" you can get a tool for them

I suspect MLCC's may be more vulnerable since they are taller.

That's the problem. You can't tell unless they are in the signal path.

What's wrong with film?

Hah! A narrow nibbler!

That sounds like a good idea. Who sells them?

if you are not doing a lot of pcbs this is probably a more reasonable price

We have a table-type pneumatic version.

They delaminate, or get junk between the layers. When we need a film cap, which is infrequent, we use an enclosed leaded part.

Digikey has gone from honest to Photoshop fake:

Good info. Thanks.

Do you think the cutter-type could add enough sideways stress to crack a smd cap or resistor?

Another solution might be mounting tabs. From an article in Electronic Products,

"The most popular currently available surface-mount solution to this problem is the molded SMD package with formed metal tab leads that run down the side of the part and under it. These compliant terminations are free to flex back and forth with the board and effectively eliminate cracking or solder joint integrity problems."

Now all we have to do is find who makes them.

Thanks. I thought the problem would be melting during reflow.

What about solid aluminum?

SMD cap cracking isn't a problem for us, or for things like cell phones or car electronics. Exotic resistors with tabs will be hard to find and big and probably cost 50x a standard part.

Everyone makes them. The problem is nobody wants them because they're priced with military parts.

Tim

I'm not worried about 0406 resistors or capacitors. it would be difficult to apply enough bend to crack them. I'm more concerned about MLCC, which is the main object of the links I provided.

What about solid aluminum?

We use aluminum electrolytics and polymer alums all the time; no problems.

Good news. Thanks.

MLCC's can fail shorted. That can be fun. Look at the EEVblog video #1037 mentioned by the OP and also #1036

Might as well watch the whole series. See Master Class diagnostics and troubleshooting at work. View cutting edge video techniques combined with exquisite narration. Drive yourself crazy with high-pitched nervous screaming, repetitive narration, glacial progress. Get it all here in one place:

EEVblog #1035 - Flaming DIY Power Supply!