This process can be broken down into three main techniques - CO2 laser (for cutting, boring, and engraving), and neodymium (Nd) and neodymium yttrium-aluminum-garnet (Nd: YAG), which are identical in style, with Nd being used for high energy, low repetition boring and Nd: YAG used for very high-power boring and engraving.
All types of lasers can be used for welding.
CO2 lasers involve the passing of a current through a gas mix (DC-excited) or, more popularly these days, using the newer technique of radio frequency energy (RF-excited). The RF method has external electrodes and thereby avoids problems related to electrode erosion and plating of the electrode material on glassware and optics that can occur with DC, which uses an electrode inside the cavity.
Another factor that can affect laser performance is the type of gas flow. Common variants of CO2 laser include fast axial flow, slow axial flow, transverse flow, and slab. Fast axial flow uses a mixture of carbon dioxide, helium and nitrogen circulated at a high velocity by a turbine or blower. Transverse flow lasers use a simple blower to circulate the gas mix at a lower velocity, while slab or diffusion resonators use a static gas field which requires no pressurization or glassware.
Different techniques are also used to cool the laser generator and external optics, depending on the system size and configuration. Waste heat can be transferred directly to the air, but a coolant is commonly used. Water is a frequently used coolant, often circulated through a heat transfer or chiller system.
One example of water-cooled laser processing is a laser microjet system, which couples a pulsed laser beam with a low-pressure water jet to guide the beam in the same manner as an optical fiber. The water also offers the advantage of removing debris and cooling the material, while other advantages over ‘dry’ laser cutting include high dicing speeds, parallel kerf, and omnidirectional cutting.
Fibre lasers are also gaining popularity in the metal-cutting industry. This technology
