Lasercutting is a technology that uses a laser to cutmaterials, and is typically used for industrial manufacturing applications, butis also starting to be used by schools, small businesses, and hobbyists. Lasercutting works by directing the output of a high-power laser most commonlythrough optics. The laser optics and CNC (computer numerical control) are usedto direct the material or the laser beam generated. A typical commercial laserfor cutting materials would involve a motion control system to follow a CNC orG-code of the pattern to be cut onto the material. The focused laser beam is directedat the material, which then either melts, burns, vaporizes away, or is blownaway by a jet of gas, leaving an edge with a high-quality surface finish.Industrial laser cutters are used to cut flat-sheet material as well asstructural and piping materials.
Generation of the laser beam involvesstimulating a lasing material by electrical discharges or lamps within a closedcontainer. As the lasing material is stimulated, the beam is reflectedinternally by means of a partial mirror, until it achieves sufficient energy toescape as a stream of monochromatic coherent light. Mirrors or fiber optics aretypically used to direct the coherent light to a lens, which focuses the lightat the work zone. The narrowest part of the focused beam is generally less than0.0125 inches (0.32 mm). in diameter. Depending upon material thickness, kerfwidths as small as 0.004 inches (0.10 mm) are possible. In order to be able tostart cutting from somewhere other than the edge, a pierce is done before everycut. Piercing usually involves a high-power pulsed laser beam which slowlymakes a hole in the material, taking around 5–15 seconds for 0.5-inch-thick (13mm) stainless steel, for example.
The parallel rays of coherent light from thelaser source often fall in the range between 0.06–0.08 inches (1.5–2.0 mm) indiameter. This beam is normally focused and intensified by a lens or a mirrorto a very small spot of about 0.001 inches (0.025 mm) to create a very intenselaser beam. In order to achieve the smoothest possible finish during contourcutting, the direction of beam polarization must be rotated as it goes aroundthe periphery of a contoured workpiece. For sheet metal cutting, the focallength is usually 1.5–3 inches (38–76 mm).
Advantages of laser cutting over mechanical cuttinginclude easier workholding and reduced contamination of workpiece (since thereis no cutting edge which can become contaminated by the material or contaminatethe material). Precision may be better, since the laser beam does not wearduring the process. There is also a reduced chance of warping the material thatis being cut, as laser systems have a small heat-affected zone. Some materialsare also very difficult or impossible to cut by more traditional means.
Laser cutting for metals has the advantagesover plasma cutting of being more precise and using less energy when cuttingsheet metal; however, most industrial lasers cannot cut through the greatermetal thickness that plasma can. Newer lasers machines operating at higherpower (6000 watts, as contrasted with early laser cutting machines' 1500 wattratings) are approaching plasma machines in their ability to cut through thickmaterials, but the capital cost of such machines is much higher than that ofplasma cutting machines capable of cutting thick materials like steel plate.
