laser beam 절단

2 편 용 접

laser beam 절단

(1)

Laser cutting offers a high precision, CNC controlled method of cutting plastic, metallic and thin ceramic components. It is a mechanised, thermal, non-contact process capable of cutting most materials with a high degree of precision and accuracy. There are two commonly used types of industrial cutting laser, CO2 and Nd:YAG. These differ in that the wavelength of infrared light produced is 10.6μm for CO2 lasers and 1.06μm for Nd:YAG lasers. Both these types of lasers produce the cut by focusing a beam of monochromatic light to a very small spot size by lenses and mirrors giving power densities in the up to 105 W/mm2. This power density is sufficient to melt locally or even vaporise most materials. Once a through thickness zone of molten or vaporised material is generated (a keyhole), a jet of assist gas, delivered co-axially through the cutting nozzle, is used to eject this material from the kerf.
The characteristics of the laser cutting process relate to the fact that the beam can be focused to a spot of less than 0.5mm diameter to achieve these very high power densities. The resulting cut edge is very square and the process is capable of cutting at very high speeds. The combination of an intensely concentrated heat source moving at high speeds also results in very little heat being transmitted to the surrounding material and, therefore, very little thermal distortion of parts.

(2)

The nozzle is used to constrict and direct the assist gas to produce a columnar flow. The flow of gas serves to push the molten metal through the kerf.
Gas which is blown into the cut to clear away molten metals, or other materials in the cutting zone. In some cases, the gas jet can be chosen to react chemically with the workpiece to produce heat and accelerate the cutting speed.

A groove, slit, or notch made by a cutting tool, such as a laser cutter or the width of a groove made by a laser cutting tool. The kerf is dependent upon the properties of the material being cut, the workpiece thickness, the lens focal length, and finally, the type of cutting gas used in the laser.