What is laser engraving? What kind of material can be engraved on?

Laser engraving is applied to high precision of robot and the latest advanced 405nm 500mW laser tube of blue-violet emission, which gets larger output power and wider engrave range. What is more, users can engrave personalized patterns on various material like leather, kraft liner board, wood and so on. Also, the latest laser kit can control laser output power to engrave via PWM.