Reading SMD Laser Etched Part Numbers

Thread Starter


Joined Jan 27, 2019
The laser etching used on many SMD parts can be very hard to read. For those that refuse to give up their secrets even under varied lighting and magnification, I have a trick that usually works quite well. All you need is a regular fluorescent highlighter pen and a UV light.


Run the highlighter over the part, as if highlighting something on a page. Then, wipe off the surface with a dry wiper or swab.

The ink retained in the etching will fluoresce more than what remains on the surface, revealing the part number in (relatively) easy to read illuminated lettering. If you desire it, some isopropanol can clean off the ink, but it's probably not required.


This has helped me in the past, I hope it can help someone else.