Marking tool for metal sheet

[misu183]

Hi!
Does anybody know if is there a mechanical method to mark sheet metal parts for industrial and traceability purposes?
We tried to use a simple stamping tool + hammer that made a letter mark but after painting it was not visible anymore.
Is there a hand machine able to do this?
Could be any shape: letter, digit, dot, dash.
It must be visible after painting, nothing more.

Thank you in advance for any opinion!

[AndersK]

Yes there is needle marking equipment available that does this but it depends of how thick coating you will apply

[bobadame]

Punch a small hole?

[DYCE]

I use an automatic center punch alot for layout. Sterret makes a nice one, but I purchased one from HF and it works good too. Here is a link to the HF punch http://www.harborfreight.com/spring-loaded-center-punch-621.html
The tip also works good as a scribe.

[misu183]

Yes there is needle marking equipment available that does this but it depends of how thick coating you will apply
70-100 microns powder coating.
Sometimes more after repainting.

[misu183]

Punch a small hole?
Doesn't help.
I need to know who produced the parts.