Fiber lasers are a popular machine tool in manufacturing. It is primarily used to work with metal workpieces and requires less maintenance.
CNC fiber laser is a CNC machine that generates a laser beam and passes it through a fiber optic cable wired to a computer-controlled laser head. It then focuses the laser beam on a narrow spot with a series of lenses, allowing it to cut and engrave different materials.
This article discusses CNC fiber laser in detail by looking at its working, types, application, alternatives, and best machines in the current market.
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CNC Fiber Laser – Explained
Numerical Control (NC) is a conventional method of programming machines to produce parts at speed and scale.
Computer Numerical Control (CNC) is an upgrade to Numerical Control, allowing you to automate machine tools with the help of software and machine controller units.
It helps fasten up the manufacturing process and allows the flexibility of revisions in programming a machine.
CNC technology is more precise, requires less human intervention, easy to program, and is economical.
Fiber lasers are named after their active gain medium, the optical fiber. They are solid-state devices that produce high-power and well-collimated laser beams from low-speed raw light.
A CNC fiber laser is a fiber laser machine integrated with CNC technology.
Today most fiber lasers are CNC-integrated. So generally, a CNC fiber laser is addressed as a fiber laser.
How does a CNC Fiber Laser Work?
In a CNC fiber laser, a fiber made of glass or phosphate absorbs raw light from pump diodes.
Then the light is simulated and amplified, converting it into a highly collimated laser beam of a predefined wavelength.
These optical fibers are doped with rare earth elements to optimize the laser beam output.
Some common rare-earth elements and the laser wavelength they produce are given in the table below. (nm= nanometer)
| Rare earth element | Wavelength of laser |
|---|---|
| Neodymium | 780 – 1100 nm |
| Ytterbium | 1000 – 1100 nm |
| Praseodymium | 1300 nm |
| Erbium | 1460 – 1640 nm |
| Thulium | 1900 – 250 nm |
| Holmium | 2025 – 2200 nm |
| Dysprosium | 2600 – 3400 nm |
The generated laser beam is then sent to a computer-controlled laser head that is moved along different axes with the help of actuators.
You can program this machine to follow a specific path to make the desired part.
Types of Fiber Lasers
Fiber lasers are classified into many types based on their laser source, operation, power, and core diameter.
These classifications of the laser help map your expectations to select a suitable laser for your needs.
Based on The Laser Source
Depending on the doping material used on the fiber laser medium, there are many fiber lasers.
For example, the Ytterbium-doped fiber laser gives a 1060 nm wavelength laser output suited for welding jobs.
Based on The Mode of Operation
Depending on the intensity and periods of the generated laser beam, there are generally two types of fiber lasers – continuous pulse wave and pulsed wave mode.
Continuous pulse wave mode lasers continuously produce high-power laser beams throughout the process.
Pulsed wave mode produces the laser beam in short period cycles.
Based on The Laser Power
Depending on the laser output power, there can be low-powered and high-powered lasers.
As their name denotes, low-powered lasers generate low-intensity laser beams, but it has high precision.
On the other hand, high-powered lasers produce high-intensity laser beams with lower precision.
Based on The Core Diameter
Depending on the path of the laser light, a fiber laser can be either single or multi-mode. Single mode has a small core diameter, and a multi-mode fiber laser will have a larger core diameter.
Smaller core diameters give higher quality laser beams than large core diameters.
When Should You Use a CNC Fiber Laser?
Commercially, the most used lasers are fiber and CO2 lasers. CO2 lasers use carbon-di-oxide as their active gain medium. The most used area is material cutting.
Most fiber lasers can convert 35-50 % of their input electric current to high-intensity lasers, whereas a CO2 laser can only convert around 10-20% of its input current to a laser beam.
For example, an 18kW fiber laser can provide the same output as a 70kW CO2 laser.
A ytterbium fiber laser has an average wavelength of 1.064 micrometers (μM), which can be absorbed by various ranges of metals and some non-metals (shorter wavelength = higher energy).
This allows it to be used for various applications like cutting and engraving jobs in manufacturing, medical procedures, defense, etc.
A CO2 laser has an average wavelength of 10μM, which limits the materials it can work with. It cannot readily work with reflective materials like metals.
On the other hand, fiber lasers can be used on various metals like aluminum, steel, copper, brass, etc.
Another popular laser in the market is the diode laser, which uses the light directly from a semiconductor diode, eliminating the need for doped rare-earth materials.
Diode lasers also have a similar wavelength as fiber lasers and have the highest efficiency of 50% electricity conversion.
But the biggest disadvantage of diode lasers is that they produce more divergent beams, which are less focused and can’t handle metal very well.
So if you are more into working with metals, a fiber laser machine is your best bet.
The initial investment for a fiber laser would cost around $15,000 and can go up to $1,000,000, sometimes, even more, depending on the machine’s power rating and feature combinations.
But, the investment is a wise one because the average lifetime of a commercial fiber laser would be around 30,000 hours.
Comparatively, diode and CO2 lasers have lower costs, but the maximum lifetime you can expect is 2,000 hours which results in fast recuring replacement costs.
Alternatives to Fiber Laser
Some popular alternatives to fiber laser cutting are flame cutting, waterjet cutting, and plasma cutting.
Flame Cutting
Flame cutting involves cutting the materials with an oxy-fuel torch. It uses pure oxygen to combust the fuel, oxidizing and cutting the material.
One big disadvantage of flame cutting is that it can oxidize any region of the exposed material, affecting its performance.
Plasma Cutting
Plasma cutting uses an electric arc passed through a gas to form a concentrated electric beam to cut materials.
The electric arc generates heat on the material surface, which is used to cut the material. It demands more electricity than fiber lasers for its operations.
Water Jet Cutting
Water jet cutting is one of the earliest methods of metal cutting. It forces high-pressure water onto the material surface, accelerating material erosion and cutting it through the water jet path.
It can cut harder and thicker materials than fiber lasers.
Best CNC Fiber Lasers
The following machines are some of the best fiber lasers commercially available for anyone to get.
BOSS FM Desktop
FM Desktop from Boss Laser is available in 20W, 30W, and 50W output power options. It has a rated lifetime of 100,000+ hours.
The beam quality from 20W and 30W FM desktop lasers is less than 1.5 M2. For the 50W model, it is less than 1.8 M2.
M2 is called the beam propagation ratio, which measures the laser beam’s focus quality. When the M2 value gets closer to one, the laser spot colligates to a tighter spot.
Beam quality is important in the efficiency of laser cutting. The higher the beam quality, the higher the precision of the laser, and the lesser time it takes to complete a job.
FM desktop is a mobile laser engraver and is ideal for small projects. It has a non-adjustable XY axis and an adjustable Z axis.
It is ideal for engraving jobs on materials like plastic, acrylic, PVC, granite, marble, aluminum, silver, brass, etc.
FM desktop comes pre-assembled. It is provided with lifetime technical support and a standard 2-year parts warranty from the company.
FSL Muse Pandora
The FSL Pandora fiber laser is available in 20W, 30W, and 50W output power options. They have an average lifetime of 25,000+ hours.
It can work with metals like titanium, steel, etc., and organic materials like leather.
FSL offers this machine in different work area sizes, but they all have the same footprint. The maximum work area you can get is 11.3″ x 11.3″.
The laser head on pandora is stable and can’t move along the XY axes. It uses a galvo head to change the focused laser beam position in the work area.
Pandora works with the manufacturer’s proprietary software, RetinaEngrave v3.0. It runs on a web interface and can be worked on most devices.
FSL provides a 1-year warranty for the machine. Depending on your chosen machine configuration, you might need to put together the machine.
Final Thoughts
A CNC fiber laser is an efficient, true-to-value product for processing metal workpieces. It also provides longer life than other types of lasers.
They are largely employed in metal-cutting and engraving jobs. Since the laser beam has an active focus plane, CNC fiber lasers are best at processing sheet metals.
If your jobs are more slanted toward engraving, marking, or etching metals, get a machine having a galvo head. It allows the laser beam to cover a larger material surface area in less time.
In a standard CNC fiber laser, you can also control laser parameters like output power, cutting speed, focus depth, etc., to adjust the processing conditions.
Frequently Asked Questions
How much thick material can a fiber laser cut?
A standard fiber laser can cut materials of up to 10mm thickness. It depends on the laser power and lens used to focus the laser. A high-powered fiber laser is best for cutting jobs.
What are the precautions to be followed for using a fiber laser?
When using a fiber laser, ensure everyone near the machine is wearing a laser safety glass. Otherwise, it can cause permanent damage to the eyes. Also, ensure that the parameters you set are tested and verified for the material. If not, it can cause fire hazards.
What are materials that can’t be worked with fiber lasers?
On a fiber laser, you cannot work with most non-metal materials like wood, plastic, fabric, stone, etc. A diode or CO2 laser is recommended for working with such material.
