Etching behavior of plastics using a near infrared laser

Laser etching of polypropylene, polyethylene (PE) and polymethyl methacrylates (PMMA) using a 532-nm Nd:YAG short pulse laser was studied. The etching behavior was varied with the surface condition of the plastic samples. For the same pulse energy of 28.3 mJ, with PP films slowly solidified from the melt instead of quenched, the etching rate was enhanced. The surface structure and crystallinity influence the etching behavior. Laser etching involves an interaction between optical absorption, heat flow, and mass motion. The etching depth increased relatively slowly, but the plane area increased greatly with increase of the energy. The etching difference between semi-crystalline PE and amorphous PMMA was shown using scanning electron microscope.