The marking of parts and assemblies is one of the important processes in modern production. The lack of labeling makes it difficult (and in some cases makes it impossible) to control the quality and volume of products. The manufacturer needs labeling to promote his brand, and the consumer needs it as a quality guarantee and a source of information about product parameters. All this requires the improvement of marking methods that do not affect the properties of the parts and products to be marked by the existing methods of marking, Laser marking systems are the most modern, technological and flexible method that allows you to control laser radiation (in time and space), to regulate its energy. When using lasers of various wavelengths, the range of materials to be marked is very wide: metals, plastics, semiconductors, rubber, leather, special alloys, wood, etc. The marking is carried out accurately, quickly and efficiently.
Equipment and technologies for laser marking:
Today, despite the variety of lasers, systems with solid-state lasers with a wavelength of 1.06 μm and CO2 lasers (10.6 μm) have received real commercial application for marking.
Scanning and portal systems, the difference:
A modern laser complex for marking, as a rule, contains: a control computer, a radiation source, transmission systems, movement and control of radiation parameters. For industrial use, laser markers with scanning and portal beam scanning systems are used.
Scanners (or scanners) move the laser beam at speeds up to 6 m / s and provide contour tracking accuracy down to 1.5 μm. Their lenses allow processing products and surfaces up to 250×250 mm in size, although usually a field of 100×100 mm is sufficient for marking. Modern motors and new technical solutions ensure the speed of the beam in gantry systems up to 3.5 m/s with high contour repetition accuracy.
At the same time, portal systems operate on a field of about 750×450 mm. Scanners are successfully used for both solid-state and CO2 lasers. Gantry systems are mainly used for CO2 lasers. This is due to the peculiarities of focusing radiation of different wavelengths, which imposes restrictions on the size of the working field and on the possibility of combining the scanning system with a specific laser emitter.
Note that scanners equally easily (due to lower moments of inertia) provide both vector and raster marking modes.
Gantry systems have the best performance in raster marking mode.
There are other methods of image formation, for example, masked or built on rotating polygons. However, such systems are not universal and are designed for a specific application. Sealed-off RF-pumped CO2 lasers are the main types of emitters for marking systems based on CO2 lasers. They have small dimensions, are easily integrated into various systems, are easy to operate and provide a power of 100–200 W (at a radiation power density in the zone of contact with the material not exceeding 105 W / cm2). In CO2 lasers, radiation pulses are formed using pulse width modulation so that the level of the pulsed power cannot exceed the power of continuous radiation. Other types of CO2 lasers (including more powerful ones) are not used in marking systems due to their large size and high cost. Due to these limitations, CO2 lasers are mainly used for marking non-metallic materials or non-metallic coated metals (painted, anodized, etc.). Click here . For these lasers, there is a technology for marking metals with the preliminary application of a special paste or compounds, for example LMM-14, and their subsequent removal, but it has not found widespread use. An example of systems based on CO2 lasers are the machines of the “Laser Center” of the “C-Marker” type and the TROTEC company of the “SPEEDY 300” series.