The laser cutting machines of the type Laser-Jet from Knuth Machine Tools have been well proven in many industrial branches for small series and single part production. Due to the compactness they need only small installation space. They are extremely flexible in use, ergonomically to handle, and very economical. As fiber lasers or CO2 lasers can be mounted with a beam power adapted to the cutting task, a very large range of possible cutting applications can be dealt with.
At the present, fiber lasers are used more and more for the cutting of sheet metal. This laser type is particularly advantageous for cutting higher reflective materials, such as stainless steel, aluminium and copper alloys, since, due to its ten times shorter wavelength compared to the CO2 laser, the laser beam enables a smaller focus and is better absorbed by metallic materials. Hence, also the Laser- Jet machine now can be equipped with fiber lasers. Different beam powers in the range from 0.5 to 4 kW can be chosen according to the cutting application in question.
Laser cutting with fiber lasers requires an enclosure that is optically dense for the laser wavelength of one micron. For that, the Laser-Jet, which is operated open at the top in the case of the CO2 laser, gets an additional housing unit on top without need of the machine to be changed in its construction and function. This enclosing unit consists of several components, the upper roof elements, which can be pushed into one another optionally for loading sheets from above, the rear wall with doors to be opened by hand, and the two front elements, which are pulled up and down by the machine itself. At the start of a cutting job, the housing closes automatically. It is checked by appropriate sensors whether the housing is completely closed, before the cutting operation is enabled. After the end of the cutting job, the enclosure re-opens, again automatically, and allows direct access to the working area of the cutting system. Therefore, it is not necessary to equip the machine with a cutting table to be pulled out manually, which in turn, reduces the need of space for the machine installation.
The almost maintenance-free fiber lasers allow a very easy use of the laser cutting machine. The beam transmission to the cutting head is maintenance-free due to the robust fiber-optic cable. In addition, fiber lasers have a significantly higher operational efficiency so that the energy costs per produced cutting surface are lower than those for CO2 lasers. Finally, the lens wear is less because the cutting head includes an easily replaceable protective glass that shields the cutting lens from sputter and dust emitted by the cutting process.
For fiber lasers with beam power up to 2 kW, one can chose between two cutting heads with different focal lengths. The head with the longer focal length of 200 mm is the more universal cutting tool, which can be used for the entire sheet-thickness range that is accessible depending on the laser power and the type of material. It is characterized by a slightly wider kerf and an extremely stable cutting operation. The cutting head with the shorter focal length of 125 mm is optimized for cutting in the thickness range up to 5 mm. By this, highest cut qualities are achieved, and the resulting kerf is of minimum width. For laser outputs greater than 2 kW, the Laser-Jet is equipped with a larger dimensioned cutting head, which allows for exchange between the two focal lengths by using retractable lens cassettes.
For further information contact Knuth South Africa on TEL: 011 822 4610 or visit www.knuth.co.za
