Vanadate laser - terminology and areas of application
The vanadate laser, chemically Nd:YVO4 is a solid-state laser (usually diode-pumped) 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
The vanadate pump is easier to pump because the absorption band is significantly wider than that of the YAG laser. The advantage here being that the wavelength drift of the pump diodes (e.g. through heating) causes less fluctuations in the output power. The optical efficiency is higher than that of the YAG laser as well, 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 variety of different materials - largely the same materials 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 and this can be a great advantage 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, it can generally be stated that any given material that is transparent to the human eye cannot be processed with near infrared. Therefore, non-coloured glasses, Plexiglas, polystyrene and the like cannot be processed. However, this can be achieved with a CO2 laser.
Low running costs
The YVO4 laser requires no additional operating costs other than the cost of electricity. Thus, the laser system is considered very cost-effective in daily use and is increasingly being used to replace traditional marking systems that use ink and labels. With both the YAG and the vanadate laser however, the pump diodes need to be replaced after approximately 15,000 - 20,000 operating hours. This is a disadvantage in comparison to fiber lasers whose pump diodes do not require regular maintenance intervals.
Unlike inkjet printers, laser systems are extremely low maintenance and have much lower running costs (no consumables, no blocked nozzles, etc.) and yet they produce a higher print quality. However, the intial investment is often considerably higher.
If the laser system is used to mark pre-printed cardboard, then a well-contrasted marking with a short marking time is produced on the substrate.
How durable are the markings with the laser system?
Laser markings in general are highly durable as the marking usually 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, do not affect the marking. This is one of the main reasons why laser marking systems have become increasingly relevant in recent years, particularly in terms of the safety-relevant marking of components - for example, to prevent counterfeiting.
In vehicles also, there are more and more components that are being marked by using a laser. This includes dashboard switches, data plates, markings for safety-relevant (e.g. seat belt buckles) and expensive engine components (e.g. camshafts).