
Lasers suck for powder coated parts. Back to dot peen.
Learned an expensive lesson this week. Marked a skid of A36 structural steel with a 50W fiber laser. Looked perfect. Sent it out for a heavy powder coat and the serial numbers completely vanished. QA rejected the whole batch.
Lasers just do a shallow surface burn. We had to go back to pneumatic pin marking. A pin actually stamps a deep enough valley into the steel that the thick powder coat can't fully fill it in and level out. You can still clearly read the stamped indent through the paint.
Set up a HeatSign benchtop dot peen marker for the guys to stamp the parts before sending them to the coaters, problem solved.
If you guys are doing heavy coated parts, drop the standard 4mm stylus. We switched to a heavy 6mm pin, set the air to 0.6 - 0.7 Mpa, and slowed the speed way down so it really hammers deep.
Side note: anyone here pin marking hardened AR400 plate? We are chewing through carbide tips right now. Any advice?