Laser marking is influenced by components reminiscent of the kind of materials, high quality of mark, and velocity. Even though CO2 and solid-state continuous-wave lasers are usually used for Laser marker metallic, they aren’t generally used for marking solid-state supplies. Therefore, this text focuses on pulsed lasers. Completely different applied sciences can be found on the subject of selecting a pulsed laser. The professionals and cons of every of those varieties are completely different, reminiscent of NdYAG, NdYVO4 (vanadate), and fibre lasers.
Moreover, the wavelength of the laser chosen should match that of the fabric being marked. Ferrous and non-ferrous metals, and treasured metals at 355 and 532 nm, take in strongly at 1064 nm. Plastics are additionally extremely absorbent at larger wavelengths.
Nd:YAG lasers have been business workhorses for greater than 25 years. These lasers had been initially lamp-pumped, however now most are diode-pumped. Diode-based programs are strong and have a excessive imply time earlier than failure (MTBF). Diodes are anticipated to final greater than 35,000 hours earlier than failure, in line with the producers. Because of the Nd:YAG laser’s beam high quality, it produces a small spot measurement.
Vanadate lasers emit mild at wavelengths of 1064 nm (inexperienced), 532 nm (blue), and 355 nm (inexperienced). A Vanadate laser’s pulse-to-pulse stability makes it ultimate for ablation marking and HAZ purposes, along with diode-pumped operation. Within the automotive business, vanadate lasers are used for day/night time marking. A high coating is eliminated to be able to expose a decrease floor for backlighting at night time with out destroying it.
About six years in the past, fiber lasers had been launched into the marking world, and so they have since been mentioned in nearly each marking alternative.
The fibre laser can’t ship the identical peak energy as Nd:YAG or vanadate lasers on account of its poor beam high quality. Attributable to their longer pulse width and bigger spot measurement, fibre lasers can anneal stainless-steel by creating extra warmth throughout the half, thereby drawing carbon to the floor. Few fibre-laser producers permit their laser sources to be built-in into marking programs by third events.
Working prices and consumables for all three laser applied sciences are nearly the identical, so an finish person can select probably the most cost-effective laser expertise with out having to compromise. The facility of solid-state lasers degrades over time, however by calibrating the system, the laser can preserve its energy as if it had been in pristine situation when it left the manufacturing facility. The identical velocity and high quality might be out there because it was when the lasers had been delivered.
The standard of lasers is specified by every producer when it comes to M2 worth. Gaussian beams present the smallest spots doable for the wavelengths and optics used on account of their M2 of 1. An Nd:YAG laser marking system has an M2 of 1.2, whereas a vanadate laser marking system has an M2. In a fibre-based laser marking system, the M2 is 1.7, so the spot measurement is bigger and the facility density is decrease. Attributable to a greater beam high quality, smaller linewidths, sharper contours, and quicker engraving (on account of a excessive energy density) are achieved. The depth of focus of a laser with good beam high quality may also be larger than that of 1 with poor beam high quality. If the depth of focus is modified, a laser with an M2 of 1.2, for instance, will go away a extra crisp mark on a curved floor than a fibre laser with the next M2.
The height energy of YAG lasers and vanadate lasers, in addition to the heartbeat repetition frequency vary, differ significantly from fibre lasers. Altering the heartbeat period of a fibre system configured as a grasp oscillator fibre energy amplifier (MOFPA) instantly impacts the heartbeat repetition charges out there for laser marking.
Plastics are often marked with lasers by engraving, annealing, ablation, and altering their colours. Choosing the proper laser for laser marking is essential for optimum outcomes. In each day and night time design purposes, vanadate lasers are efficient ablators on account of their brief pulses and pulse-to-pulse stability. Pad-printed plastic base materials may be eliminated with out damaging the painted high floor. Ablation can also be generally used to mark anodized aluminium, which is among the many most forgiving supplies.