Vanadate laser - terminology and areas of application
The vanadate laser, chemically Nd:YVO4 is a (usually diode-pumped) solid-state laser similar to the Nd:YAG laser, but with a different host crystal (YVO instead of YAG). A neodymium-doped yttrium-vanadate crystal is used in the vanadate to generate the laser beam. As the excitation or laser emission takes place via the neodymium doping, the vanadate laser has the same wavelength as the YAG laser (1064nm).
Advantages of the laser system
Data plate made of anodized aluminum with plain text and machine-readable codes
The vanadate pump is easier to pump, the absorption band being significantly wider than that of the YAG laser. This has the advantage that the wavelength drift of the pump diodes (e.g. through heating) causes less fluctuations in the output power. The optical - optical efficiency is higher than that of the YAG laser, therefore the removal of waste heat is less critical or the output power (with the same crystal volume and same crystal geometry) is higher.
A vanadate laser can be used to mark a wide range of different materials - largely the same as what a YAG laser can mark. The laser marks virtually all metals, plastics and partly organic materials. The vanadate laser can deliver more pulses per second than the YAG laser. This can be advantageous for fast markings on plastic, as there is still pulse overlap.
A laser can generally only interact with a workpiece if it has sufficiently high absorption. Reflected or transmitted power is - obviously - useless for material processing.
As the laser emits in near infrared, as a rule of thumb it can be stated that any material that is transparent to the human eye cannot be processed with near infrared. Therefore, non-colored glasses, Plexiglas, polystyrene and the like cannot be processed. This is possible with a CO2 laser.
Low running costs
The YVO4 laser requires no additional operating costs besides electricity costs. Thus, the laser system is considered very cost-effective in daily use and is increasingly replacing conventional marking systems that use ink and labels. With both the YAG and the vanadate laser, however, the pump diodes should be replaced after approximately 15,000 - 20,000 operating hours. This is a disadvantage compared to fiber lasers whose pump diodes are not subject to regular maintenance intervals.
Unlike inkjet printers, laser systems offer higher print quality, lower running costs (no consumables, no blocked nozzles, etc.), and extremely low maintenance. However, the investment is significantly higher.
If pre-printed cardboard is marked with the laser system, a well-contrasted marking with a short marking time is produced on the substrate.
How durable are the markings with the laser system?
Marking of a hydraulic hose used in harsh industrial environments
Laser markings generally have a very high durability, as the marking often takes place in the volume of the material - and not just on the surface. Unlike printed images, texts or barcodes, laser markings are resistant to abrasion and completely smudge-proof. Even solvents, oil, weak alkalies and acids, as well as high temperatures, cannot affect the marking. This is one of the reasons why laser marking systems have become increasingly relevant in recent years when it comes to the safety-relevant marking of components - for example, to prevent counterfeiting. In cars too, there are more and more components that have been marked using a laser. This includes dashboard switches, data plates, markings for safety-relevant (e.g. seat belt buckles) and expensive components (engine components e.g. camshafts).
