Here at Thinklaser we often get asked by customers which is the best for marking, Nd:YAG or Fibre lasers and the answer in all but the most specific of applications is Fibre. Here’s why…..
The YAG or Nd:YAG laser was introduced over 30 years and quickly became the workhorse of industry, originally lamp-pumped they evolved over time to make diode pumping the most common variant.
The Fibre or Fiber* laser (*for our American friends) is a relative newcomer, arriving on the scene around 2005, with the same 1064nm wavelength and a number of key benefits they can be a direct replacement for the Nd:YAG laser, although it is recommended to thoroughly test each substrate material and application to ensure compatibility.
Key Benefits of Nd:YAG over Fibre
Beam Quality: The key aspect of the Nd:YAG that out performs that of the Fibre laser is the quality of the beam. Essentially the laser marking beam quality is specified terms of an M2 value, usually given in the lasers technical specifications. A Gaussian beam has an M2 of 1 and allows for the smallest spot size in relation to the wavelength and optics used.
The best beam quality found in Nd:YAG laser marking systems has an M2 value of 1.2. Fibre-based systems typically have an M2 value of 1.6 ~ 1.7, meaning a larger spot size and less power density. For example; the peak power of a Fibre laser is in the 10kW range while the peak power of a Nd:YAG laser is in the 100kW range.
Basically, better beam quality produces;
- smaller linewidths,
- sharper contours,
- higher marking speed (because of high power density), and
- deeper engraving.
Good beam quality also provides better depth of focus than a laser with lower beam quality. Marking on a curved surface using a laser with an M2 of 1.2, for instance, will give a crisper mark as the depth of focus changes than will a laser with a higher M2 such as that from a Fibre laser.
Key Benefits of Fibre over Nd:YAG
The benefits of Fibre over Nd:YAG laser sources are wide and varied and almost always surpass the difference in beam quality.
Reliability: Fibre lasers have no optics to align or adjust or consumables to wear out, so maintenance is minimal with little or no equipment downtime. They are extremely compact and the technology makes them less vulnerable to misalignment and adjustment problems that you might see in a Nd:YAG laser marking machine. Typically MTBF (Mean Time Before Failure) is in the region of 30,000 to 50,000 hours against 10,000 to 20,000 hours for a diode-pumped Nd:YAG laser.
Faster Processing: Fibre lasers are instant turn on with the ability to vary pulse power, energy pulse, width and modulation rates on-the-fly. Nd:YAG systems generally need a “warm up” period to allow for the laser to stabilise.
Efficiency: Fibre lasers have a wall plug energy efficiency of up to 50% compared to around 1.3% for the Nd:YAG. If running costs and Green credentials are important to you then Fibre is the only way to go.
E.g.: 2 x 8hr shifts x 365 days per annum @ £0.112/ kWh
20w Fibre @ 170watt / hour costs £111.20 per annum in electricity
20w YAG @ 6Kwatt / hour costs £3925.48 per annum in electricity
Size: Fibre lasers have a significantly smaller footprint compared to their Nd:YAG counterparts, easily housed in rack mount format, they take up little room within the laser system. Generally systems up to 200W can be air cooled, negating the requirement for a water chiller unit which in turn reduces the space and power consumption requirements.
Productivity: Lower running costs, minimal maintenance requirements, longer MTBF, reduced down-time / high utilisation combined with a small footprint all contribute to giving productivity boost per square meter of valuable factory floor space and an enhanced return on investment.
Unless you have a specific application that requires a high peak power and an improved depth of focus offered by Nd:YAG then Fibre is the way to go. The benefits of using a Fibre laser far outweigh the niche benefits associated with the improved beam quality and, with the continued development of Fibre lasers even this difference is gradually being eroded away.
Whether you decide on a Fibre or a Nd:YAG system, you can rely on Thinklaser to provide the solution to your marking challenges. From off-the-shelf stand-alone solutions to fully bespoke systems our Lightwriter and M-Series systems will “make light work for you”.