About Laser Marking
The Principle of Laser Marking
The acronym "LASER" describes accurately the principle of operation: "Light Amplification by Stimulated Emission of Radiation." From a practical viewpoint, a laser is a radiation source that emits a tightly bundled beam of light. Depending on the laser type, this high intensity beam of light is characterized by a certain wavelength. For marking, a lens system focuses the laser beam onto the material to be marked. The reaction with the surface causes the material to change leaving it discoloured or engraved.
Just how the material changes depends mostly on the laser's wavelength and the performance specifications in the laser beam's focus, but also on the material itself and the processing parameters such as the laser's power and marking speed.
The most widely used marking procedure is vector marking. Using this method, the laser beam is directed by two mobile mirrors ("galvanometer scanner") in the X and Y direction on the work piece. The laser beam "draws" the desired marks on the material's surface. The completed marking is as a result of a plethora of lines, or vectors. This method's primary advantage lies in its high flexibility, ease of programming and the high quality of the marking achieved. Additionally there is raster and mask marking. Currently raster marking is used in the printing industry to expose film layers. For pure marking applications it has been almost completely supplanted by vector marking. Mask marking is the procedure with the fastest marking times and is used to label high volume of production products. Compared with the vector method, mask marking is much less flexible.
Advantages compared to conventional methods
Until recently, conventional methods such as stamping, molding, engraving, etching, pad printing and ink jet printing dominated in the product marking field, but now the use of laser markers has made major inroads across almost all sectors where that technology was firmly established. Since laser marking systems are purely optical tools that require no additional printing materials such as toner, ink or solvents they are the most environmentally friendly option. Tool wear is non-existent. Only the work piece material is affected. The quality and reproducibility of marking remains consistently high.
The laser marking system can be configured in a number of ways and installed in difficult-to-access spaces. Marking of sensitive parts can be achieved. The major benefits of laser markers are:
- Speed of marking
Up to 240m/min for "on-the fly“ marking using certain SUNX LP- 400 and
LP-V10 series systems - Extremely fine marking (to 0.2mm height and width)
Particularly important with stringent manufacturing tolerances and very
short cycle times
A laser marker can easily be integrated into automated manufacturing processes. All functions are computer controlled with data transferred via existing interfaces (RS232, digital I/O, etc.).
Application examples
Industrial markings must fulfill certain fundamental criteria. The marking must be permanent, impervious to being erased, and the contrast to the base material must be high. Laser marking systems can be used almost everywhere; packaging and automotive industries, manufacture of electrical and electronic components, the pharmaceutical, medical and cosmetics industry as well as in machine building and plant engineering. Because laser marking systems require little space and are robust, they can be easily integrated into assembly lines and individual work stations.
