Choosing the right laser engraver for your application shouldn’t be a hassle. In this blog, we review the main points that should be considered prior to purchasing a laser engraver. We’ll explain how they work, the aspects associated with them, the different types, the advantages of fiber lasers and the optical power requirements for laser direct part marking of metals.
Types of Fiber Lasers
All fiber lasers have specific characteristics and distinct wavelengths that make them appropriate for very specific applications.
For example, ER-doped fiber lasers have a wavelength of 1550 nm and are mainly used in telecommunications. Thanks to ER-doped fiber lasers we have high-speed internet and voice over IP.
YB-doped fiber lasers have a wavelength of 1064 nm and are used for material processing. They are particularly suited for the laser marking and laser cleaning of metallic products. These are the lasers used in Laserax’s LXQ, LXQ 3D and LXQ 3D Vision.
The variety of wavelengths found in fiber lasers explains their widespread use in many applications.
How Do Fiber Lasers work?
A. Pump Module
It all starts from the light emitted by Laser diodes (1) that is transported to the gain medium (2) by, you guessed it, fiber optics. It pumps the active medium with photons that in turn excite just the right kind of photons from the gain medium.
B. Resonator Module
The active gain medium (3) is an optical fiber doped with combinations of rare earth elements, such as erbium (Er), ytterbium (Yb), neodymium (Nd), dysprosium (Dy), praseodymium (Pr), thulium (Tm) or holmium (Ho). Laserax’s fiber lasers use ytterbium-doped fiber optics as a gain medium. It results in a laser beam with a wavelength of 1064 nm, which has great absorptivity with most metals.
Fiber lasers use Bragg gratings (2 & 4) to reflect the photon back and forth inside the resonator (B). A Bragg grating is a piece of glass that has “stripes” in it. These stripes alter the refractive index of the glass; any time light passing between these stripes a very specific portion of the light spectrum are refracted back. This is how the resonator of the fiber lasers is created.
One of the Bragg grating is semi-reflective (4), it will let only the light at the specific wavelength out of the resonator. And that is how the laser beam (7) is created!
C. Beam Delivery
The laser beams used in direct part marking applications are usually expanded and focused using a beam expander and a lens that are located inside the laser head (6).
Fiber laser used in Laserax’s laser marking systems use motors to control mirrors that direct the beam to the specific targeted locations to be engraved. These motors are of a special kind called galvanometer motors (or galvos) they allow a computer to control the movement of the laser very precisely at high-speed. The galvos are also located, along with the other optical element discussed earlier, in the laser head (6).
Advantages of Fiber Lasers
Wavelength flexibility and variety allow the use of fiber lasers for direct part marking of metal and many other materials.
The use of optical fibers as an active medium ensures simpler delivery to the focusing element.
Good beam quality is easier to achieve due to the optical fiber light’s guiding properties.
Fiber lasers are among the most energy-efficient lasers thanks to their low levels of electricity consumption and small heat management requirements.
They are more compact than gas and solid-state lasers of equivalent optical power.
Fiber lasers have a lower cost of ownership than other types of lasers.
They require low maintenance.
With a mean time between failure (MTBF) of up to 100 000 h, they have a long useful life.
Fiber lasers are very stable, which makes them ideal for industrial environments.
Fiber Laser Engravers
In the previous sections, we have described the basic components of a typical fiber laser and the advantages of that technology. Fiber laser engravers use the high-intensity laser beam controlled by galvanometer motors to deliver to the exact position at very precise settings for a perfect label at all times.
How Much Optical Power Do You Need for Laser Direct Part Marking?
All other factors being equal, the more powerful the laser, the faster the marking or cleaning.
Many factors influence laser marking speed, such as the font used for the text or numbers, dimensions of the Data Matrix Code (DMC), barcode size, the use of a pale background to improve contrast, etc.
For more details, refer to our blog post, entitled Laser Marking Time Estimate for Industrial Applications. In that post, you will find tables with laser marking times under different operating conditions and how the power of the laser contributes to fast direct part marking.
Laserax has developed pulsed fiber laser markers and cleaners that range from 20 to 200 w average optical powers.
The Laserax Advantage
Laserax has developed specialized laser markers for metal processing. But that’s not all. It also offers options and laser safety enclosures for complete laser engraving solutions.
Some of our most sought-after options are: a cabinet with laser source and controllers, human-machine interface (HMI), dust and fume extraction and filtration unit and an air knife that keeps the laser lens dust-free.
All of our laser safety enclosures ensure that no laser hazard mitigation procedures are required and no personal protective equipment (PPE) is needed for any of your employees. Lasers, options, and enclosure are bundled in Laserax’s modular approach.
How to Choose the Best Laser Marker for Your Application
Any serious pricing estimate for an industrial laser marking system will require information about the process currently used in your facilities. Following is a list of information to help you get started:
- Determine the material(s) that is(are) going to be marked.
Aluminum, steel, stainless steel, magnesium, zinc, lead, tin, and many others.
- Determine what information you and your clients need to trace.
Alloy number, cast house ID, customer, and internal reference number, part number, shot number, mold number, cavity number, date and time stamps.
- Determine the types of marking you are going to use.
It could be plain text or numbers, logo, DMC and/or barcode. You can learn more about different encoding mechanisms in our guide on industrial traceability.
- Establish how much time you have to carry out the marking.
- Compare the time required with the time available to do the marking.
Laserax’s years of experience in laser marking in the primary metals industry have given it unique expertise in the estimate of laser marking time. Get in touch with our laser technology expert for such an estimate for your unique application.
- Get a quote for your laser marking application; it is the next logical step.
These tips most certainly work in practice; however, some other considerations need to be accounted for if you want your laser marker integration to be a success in an actual industrial environment.
In a nutshell, Yb-doped pulsed fiber lasers are the best choice for laser direct part marking and other processing of metals. That is why Laserax has developed the LXQ series that use this specific type of laser source.
The material to be marked, extent and complexity of the marking, contrast requirements, and time available to do the marking will determine the minimum power level required from the laser in your marking system. More powerful lasers will take less time to do the work than less powerful lasers.
Laserax has laser marking systems ranging from 20 to 200 W. You should also consider the types of options and kinds of enclosures you may need for the easiest integration within your assembly lines to ensure the safety of your employees.