In vaporization cutting the focused beam heats the surface of the material to boiling point and generates a keyhole.
The keyhole leads to a sudden increase in absorptivity quickly deepening the hole.
As the hole deepens and the material boils, vapor generated erodes the molten walls blowing ejecta out and further enlarging the hole.
Non melting material such as wood, carbon and thermoset plastics are usually cut by this method.