Methods for Cutting Using Lasers
There are several methods of cutting materials using lasers. These methods include vaporization, melt and blow, thermal stress cracking, stealth dicing, and reactive cutting.
Vaporization cutting involves heating the surface of the material with a focused laser beam until it reaches a flashpoint and creates a keyhole. The keyhole deepens as vapor erodes the molten walls and enlarges the hole. This method is typically used to cut non-melting materials such as wood, carbon, and thermoset plastics.
Melt and blow, also known as fusion cutting, uses high-pressure gas to blow molten material out of the cutting area. This reduces the power requirement and is typically used to cut metals.
Thermal stress cracking exploits the sensitivity of brittle materials to thermal fracture. A laser beam is focused on the surface to cause localized heating and thermal expansion, resulting in a crack that can be guided by moving the beam. This method is usually used to cut glass.
Stealth dicing is a process used to separate microelectronic chips from silicon wafers. It uses a pulsed Nd:YAG laser with a wavelength well adapted to the electronic band gap of silicon.
Reactive cutting, also known as burning stabilized laser gas cutting or flame cutting, is similar to oxygen torch cutting but uses a laser beam as the ignition source. It is mostly used for cutting carbon steel over 1 mm thick.
