Good results can be achieved by marking polyethylene with an infrared fiber laser.
Aluminum Laser Marking
Lasers provide the flexibility to engrave text, company logos, barcodes, 2D Codes.
Laser Marking of an Aluminum Billet
Here is a demonstration of laser marking on one of the ends of an aluminum billets.
Laser marking of an aluminum billet
In this video, Laserax LXQ 3D is engraving text on the side of an aluminum billet.
Laser Annealing of Stainless Steel
Lasers can be used to slowly heat stainless steel providing interesting shades and colors