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About Laser Cutting
Laser cutting is a hot cutting manufacturing and fabricating
process using an industrial laser for the cutting of material, usually
metal. “Laser” is an acronym for Light Amplification by Stimulated
Emission of Radiation. The beam of the laser is an extremely coherent
radiation of a wavelength, meaning the beam will not dissipate like conventional
light beams. The focused beam of the laser makes it best suited for the
energy transfer necessary to cut metals by melting or burning the material
along a cut line. Assist gas sweeps the cut area clean. The cutting process
is precision controlled through a combination of CNC and CAD computer
systems.
Distinct advantages exist for using laser cutters over other cutting
methods. Excellent control of the laser beam with a stable motion system
achieves an extreme edge quality. Laser-cut parts have a condition of
nearly zero edge deformation, roll-off or edge factor. Laser cutters
have higher accuracy rates over other methods using heat generation,
as well as
water jet cutting. Laser cutting is faster than conventional
tool-making techniques and has a quicker turnaround for parts regardless
of complexity because design changes can be easily accommodated. Many
different kinds of laser cutting services are available, including laser
drilling, laser etching, laser engraving, laser machining and laser micromachining,
all resulting in little waste.
Laser cutting does have a few disadvantages. The material being cut gets
very hot, so in narrow areas thermal expansion may be a problem. Distortion
can be caused by oxygen, which is sometimes used as an assist gas, because
it puts stress into the cut edge of some materials; this is typically
a problem in dense hole patterns. Lasers also require high energy, making
them costly to run. Laser cutters produce a recast layer in the kerf
that may be undesirable in some applications. Lasers are not very effective
on metals such as aluminum and copper alloys due to their ability to
reflect light as well as absorb and conduct heat. Neither are lasers
appropriate to use on crystal, glass and other transparent materials.
Lasers, even low-powered ones, are potentially hazardous to a person’s
eyesight. The laser beam can focus on an extremely small spot on the
retina, causing permanent burn damage in seconds. Infrared and ultraviolet
lasers are even more dangerous because the “blink reflex” protects
the eyes only if the light can be seen. Lasers are divided into five
safety classes based on wavelength and maximum output power. Lasers in
Class I are inherently safe because of a low output power or an enclosure
that cannot be opened in normal operation without the laser automatically
switching off. In Class II, the blinking reflex will prevent eye damage;
most laser pointers are in this class. The lasers in Class IIIa have
large beam diameters and are mostly dangerous in combination with optical
instruments, which change beam diameter. If the beam of a laser in Class
IIIb enters the eye directly or is reflected into the eye, damage can
result. Class IV lasers are highly dangerous. Damage to the eyes and
skin can be caused even by indirect scattering of light from the beam.
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