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SMT electronics assembly manufacturing forum.


unmarked chip resistors

Views: 3344

#78849

unmarked chip resistors | 8 September, 2017

Is the industry really moving toward unmarked chip resistors? I've been seeing a lot of unmarked 0603 resistors lately, and when I check the data sheets, all their photos are of marked parts, and they don't say anything about it.

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#78856

unmarked chip resistors | 11 September, 2017

Absolutely - it is probably cheaper! Soon they might start doing it with the transistors, diodes and ICs too. Why would you need a sophisticated AOI machine then? What would quality control look for? It is annoying, considering the amount of different values of resistors that you can have.

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#78858

unmarked chip resistors | 11 September, 2017

Our AOI machines have actually caught wrong resistors before. A reel gets swapped, a vendor sends a wrong part, things happen. To think that we can't rely on resistor markings anymore, that just sucks.

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dwl

#78863

unmarked chip resistors | 11 September, 2017

I wish they would marking chip capacitors. I never understood why they didn't...

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#78865

unmarked chip resistors | 12 September, 2017

You mean why did they stop marking chip caps.

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#78880

unmarked chip resistors | 15 September, 2017

Yageo announced their decision to stop marking SMD resistors back in 2013, and since then we have started to see 0603's that aren't marked, but larger sizes - so far - are still showing a value.

0402's have never been marked, and I doubt they ever will due to their size.

SMD caps are not marked, and we deal with that OK, so why should we not be able to cope with unmarked resistors?

If a resistor gets burnt, or fails, we can usually assume a value, and try it. This is less easy with a cap that has blown, unless it is obviously a decoupling cap.

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#78883

unmarked chip resistors | 15 September, 2017

It gets tricky when resistors that your customer specified are no longer marked, but they think that unmarked resistors are a defect, and the manufacturer hasn't updated their data sheet to show the parts as unmarked, so you don't have anything to show your customer to prove that you're using the correct approved parts.

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dwl

#78884

unmarked chip resistors | 15 September, 2017

From my perspective, I like marked parts because I can use AOI to verify the correct parts are being placed in production. If an operator is going to load the wrong reel, I prefer to find out on the first PCB rather than after 5000 wrong parts have been placed.

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