Laser markers are capable of doing high-contrast, high-speed processing on almost all plastics and resins.
The traditional (infrared) fiber laser allows the marking of a wide range of components. If we also consider the MOPA version – i.e. with variable pulse – the number and type of possible laser processing increases. Less common are UV and CO2 laser markers, even though they have high performance on this type of material. The revolution in laser marking on plastic came with the advent of FlyPeak laser technology, which combines high peak power with short pulse duration.
We will delve into all these lasers at the end of the article. LASIT has gained a great deal of experience in parameter setting and marking tests with all sources.
Expansion is a laser marking process that melts the surface of the plastic. The material, brought to the boiling point, melts. The subsequent cooling is very fast. The gasified and vaporized bubbles are found in the surface layer of the base material and create a whitish bulge. This causes a tangible, therefore embossed, marking effect. The effect of these bubbles is most visible if the base material is dark. In this case, the laser works at reduced power but with very long pulses. This process can be applied to all polymers, where the composition varies the final color: light or dark.
Carbonization makes it possible to create strong contrasts on shiny surfaces. During this process, the laser heats the surface of the material (to a minimum of 100° C), causing the emission of oxygen, hydrogen, or both. The result is a dark area with a high concentration of carbon.
During carbonization, the laser works with a lower than average energy. This results in a longer marking time than other processes. Carbonization can be applied to polymers or biopolymers such as organic materials such as wood, leather and hide. Mainly used for darkening, its contrast is not maximal on components that are already dark .
Laser marking involving a color change process is basically an electrical process, which rearranges the macromolecules (by changing the direction). In this case, the material “dilates” by partially expanding. It is not removed or eliminated. The “pigment” elements in the base material always contain metal ions. Laser radiation changes the crystalline structure of the ions and the level of hydration in the crystals. Consequently, the composition of the element itself undergoes a chemical transformation, causing a color change due to the greater intensity of the pigment.
Unlike the previous processes , the laser frequency is at maximum. Each pulse has a reduced energy. This is to avoid excessive expansion of the material or the removal of part of the surface.
All plastic polymers can undergo this color change process . In most of the cases, the color change is towards a darker color; a light effect is rarely obtained.
Removal is used on multilayer plastic components (laminates). As the name suggests, this process consists of the removal of the surface layers of the base material. The color difference between the different layers creates color contrasts. This color contrast is used to create the backlit components of the cars.
All Night & Day components of cars are made by removing the plastic’s surface layer.
Unlike other technologies, laser marking is indelible and resistant to wear, heat and acids. For code marking, this is essential to guarantee the traceability of the component over time. For the logo markings or graphics, this increases the recognition and quality of the brand.
The wavelengths of infrared rays (IR, Infrared) are the most versatile for laser processing. This laser is by far the one most used in industries for marking applications. It replaced the diode back in 2006-2007 and is the undisputed king of the market.
The MOPA laser marker is able to mark plastics with legible results and with high contrast. The variable pulse guarantees optimal results and simplified marking management. It performs work more quickly than the traditional fiber laser.
The FLYPEAK combines high peak power with a very short pulse duration compared to other lasers in its class. This laser marker produces a “cold” marking. It guarantees the absence of burns and high quality of the contrast: this is possible because it works in a range from single shot to 100kHz with a pulse width between 2 and 10 ns.
The Fly UV ultraviolet marking laser is used to mark delicate materials. Fly UV colors the surface of the product with a photochemical process, and the heat produced by the marking is so limited that it does not damage the component.
The FlyCO2 is the ideal laser marker for plastics and is known for having an effect on most organic materials, compared to other lasers where marking is not possible. The CO2 laser markers have a power from 10W to 70W, with air or water cooling.
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