Laser marking: choosing the best laser for your application

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Laser marking: choosing the best laser for your application

Today marking lasers are of many types and can mark all materials . If until a few years ago there were limits in terms of quality and range of markable materials, today this is no longer the case.
Depending on the type of material and the expected result, there is a suitable laser marker .

Due to the great abundance of possibilities, choosing a suitable laser is not easy and represents a challenge for many operators in the sector. Let’s try to clarify in this article the things to take into consideration to choose the right laser marker for our needs.

First we need to understand the characteristics of the laser and the material properties of our components.

The main parameters to consider when choosing are: the type of material , the quality of the marking and the aesthetic effect we want to obtain and the speed . The speed, in the case of stand alone laser markers, is identified with the cycle time. The cycle time consists of the time required for a component to complete its entire marking path, from the introduction into the system to the reading (if any) of the 2D code .

Among the lasers that you have heard of most often there are the Fiber lasers , the Wave ones, the UV ones and certainly CO2 . Each of them adapts to one material more than another. Generally speaking, we know Fiber for its total effectiveness on metals . The Green Wave laser is instead more suitable for plastics , such as the more famous UV laser.

The CO2 laser is the most used for marking organic materials . Within the Fiber category there are also technological variants suitable for particular applications. We will deepen them at the end of this article, we are talking about the MOPA laser and the Picosecond laser .

It is important to understand how the material to be marked absorbs the laser light at the wavelength of the laser itself. Ferrous and non-ferrous materials have optimal absorption at 1064 nm, while precious metals do so at 355 and 532 nm.

Plastics also absorb longer wavelength laser output.

Laser technologies

The Nd: YAG laser was introduced to the market almost 30 years ago and is perhaps the most famous and well-known in the industry. This is due to the large amount of applications it covers. Originally these lasers were pumped by lamps . They later evolved, replacing lamps with diodes . Diode-based systems are robust with an excellent life expectancy . An advantage of Nd: YAG lasers is the quality of the laser beam . This is due to the small spot size . This, coupled with the short pulses , produces high peak powerwhich can be useful in deep engraving with sharp and clear markings and small fonts.
The vanadate laser can emit at three different wavelengths : 1064, 532 (green) and 355 nm (blue). Vanadata lasers are also diode pumped and are particularly suitable for the ablation process and for heat affected areas applications. One of the major fields of application of the vanadate laser are Day & Night Markings . In this case the laser removes the surface coating of the component (usually they are internal buttons of cars) exposing the underlying surface with the functional indicator. As these buttons are back-lit , their effect is what we all know on the stereo, windows, air conditioning buttons.

With the advent of the Fiber laser , there has been a real revolution in the world of laser and marking. The fiber laser has become the center of every application and has been tested and refined to suit almost any market demand Marcatori laser prezzo.

 

One thing to keep in mind is that the output power of all solid-state lasers degrades over time, but it is possible to calibrate the system to maintain the same power in the laser as the day it left the factory. This will allow the laser to maintain the same quality and speed as the sign of the day it arrived and was put into production.

The wavelength of the Fiber laser is 1064 µm , with an extremely small focal diameter. This leads to an increase in intensity , which is 100 times greater than that of CO2 lasers, with the same average output power.
Typical reference values ​​of a marking system
TYPICAL VALUES YAG VANADATO FIBER
Pulse Duration (ns)
10-150
5-30
10-200
Beam quality (M²)
<1.2
<1.2
<2
Peak Power (kW)
High, 100 kW range
Medium, 80 kW range
Low, 10 kW range
Average Power (W)
5-30
5-40
10-50
Pulse repetition frequency range
5-80 kHz
20-120 kHz
20 kHz – 1 MHz

Properties of the radius

Gaussian ray has a M ² of 1 and allows for a smaller spot in relation to the wavelength and the optics used. The best possible beam quality in Nd: YAG and vanadate laser marking systems has a m ² of 1.2 . Fiber -based systems typically have a ² value of 1.7 . This means a larger spot size and lower power density. Better beam quality means finer lines , sharper outlines , faster marking speed(for higher power density) and deeper engraving .

Pulse repetition frequency

YAG and vanadate lasers are very different from fiber lasers in peak power and pulse repetition frequency range. The duration of the pulse can be adjusted in the case of particular fiber systems such as the MOPA laser.
Applications

The most common terms used in laser marking include: etching, annealing, selective ablation, and surface removal . Depending on the application and material, one laser is more suitable than the other. 

 

If we look at the Day & Night components, the vanadate laser can work well. The surface removal process adapts to the characteristics of this laser, which are short pulse and repetition rate. Speed ​​is essential to avoid burning the plastic component.

Ablation is also a commonly applied process in laser marking anodized aluminum .

Another very common application for which a particular Fiber laser is effective is annealing on medical components. They are usually made of stainless steel and titanium. Naturally, we are talking about all components such as prostheses, surgical instruments, dental components. The high peak power of the Picosecond Laser here is ideal for obtaining black and impalable markings .

The resistance of this laser marking to passivation cycles and corrosion due to aggressive agents is more important than in other cases. This is because laser marking can be functional to indicate to the surgeon some important dimensional information on the component in question. The scarcity of the reflective effect of the Picosecond laser is another factor that favors this product over others in the medical field.

Choose a laser marker
The world of lasers and marking is destined to grow and evolve year after year. The technology will have to meet the changing needs of the manufacturing environment and the demands of a demanding market. The choice of laser marking supplier is important as the offer is vast and making mistakes is easy. Relying on those who know their work also means benefiting from the advice of an expert who knows how to customize his offer to our needs and not the other way around.
LASIT has been an expert in customizing its laser systems for the past 30 years. From mechanics to software we do not stop at any request and we protect the interests of our customers at 360 degrees. Here you can find an article about 10 Guidelines we have identified for the right choice of your laser marker .

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