LASER CUTTING

(Redirected from Laser cutter)
Laser cutting is a technology that uses a laser to cut materials, and is usually used in industrial manufacturing. Laser cutting works by directing the output of a high power laser, by computer, at the material to be cut. The material then either melts, burns or vaporizes away leaving an edge with a high quality surface finish. Industrial laser cutters are used to cut flat-sheet material as well as structural and piping materials. Some 6-axis lasers can perform cutting operations on parts that have been pre-formed by casting or machining.

Contents

Comparison to mechanical cutting

Types

Process

See also

Manufacturers

Distributors

Comparison to mechanical cutting

Advantages of laser cutting over mechanical cutting vary according to the situation, but two important factors are the lack of physical contact (since there is no cutting edge which can become contaminated by the material or contaminate the material), and to some extent precision (since there is no wear on the laser). There is also a reduced chance of warping the material that is being cut as laser systems have a small heat affected zone. Some materials are also very difficult or impossible to cut by more traditional means. One of the disadvantages of laser cutting may include the high energy required.

Types

The most popular lasers for cutting materials are CO₂ and Nd:YAG, though semiconductor lasers are gaining prominence due to higher efficiency. Typically there is a choice between a DC (direct current) and RF (radio frequency) powered resonator (laser generator). The fundamental choice of beam generation method can have significant impact on productivity and life cycle costs due to the differences between the two types. DC resonators have internal electrodes encapsulated in the cavity glass where RF resonators have external electrodes.
In addition to the power source, the type of gas flow can affect performance as well. In a fast axial flow resonator, the mixture of carbon dioxide, helium and nitrogen is circulated by a turbine Slab or diffusion cooled resonators have a static gas field that requires no pressurisation or glassware, leading to savings on replacement turbines and glassware.

Process

Laser cutters usually work much like a milling machine would for working a sheet in that the laser (equivalent to the mill) enters through the side of the sheet and cuts it through the axis of the beam. In order to be able to start cutting from somewhere else than the edge, a pierce is done before every cut. Piercing usually involves a high power pulsed laser beam which slowly (taking around 5-15 seconds for half-inch thick stainless steel, for example) makes a hole in the material.
There are generally three different types of industrial laser cutting machines. Flying optics lasers usually feature a stationary X and Y axis table where the cutting laser moves over the work piece in both of the horizontal dimensions. Flying optics-type cutters are popular due to the low cost of stationary tables, and their higher cutting speed limits, since the mass of the optics is much smaller than the mass of the table.

Flying optic machines must use some method to take into account the changing beam length from near field (close to resonator) cutting to far field (far away from resonator) cutting. Common methods for controlling this include collimation, adaptive optics or the use of a constant beam length axis.
Both Hybrid and Pivot-Beam lasers usually involve a table which has the capability of X axis travel. Because of this, the head has to move only in two directions (usually the ones with the shortest runs), thus improving its efficiency, as the path traveled is shorter. Pivot-Beam lasers offer the highest performance per watt and the most reliable cut consistency of the three styles. Hybrid style lasers typically can cut thicker material per watt than other types of laser cutting machines. This is due to the fact that fewer mirrors are required to deliver the laser beam to the cutting head. Each time the laser beam gets reflected by an optic a certain amount of power is lost in the reflective optic.
Pulsed lasers which provide a high power burst of energy for a short period are very effective in some laser cutting processes, particularly for piercing, or when very small holes or very low cutting speeds are required, since if a constant laser beam were used, the heat could reach the point of melting the whole piece being cut.

See also

★ Laser engraving (aka laser etching) is a similar process in which the laser does not cut fully through the material

★ Plasma cutting

★ Laser-microjet

★ Water jet cutter

★ Laser converting

Manufacturers

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Distributors

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