Laser Cutting Guide 2025 (Part 3): Fiber Lasers & The Magic of Metal

If you try to engrave bare aluminum or stainless steel with a CO2 or Diode laser, nothing happens. The beam just bounces off the shiny surface like a mirror. To make a permanent mark on metal, you need to change the physics.

Welcome to the world of Fiber Lasers. These are the machines that engrave serial numbers on firearms, logos on Yeti cups, and intricate patterns on jewelry. They are fast, terrifyingly powerful, and completely different from the gantries we discussed in Part 1 and 2.

The Technology: 1064nm & Galvo Heads

Fiber lasers operate at a wavelength of 1064nm. This specific frequency interacts perfectly with the crystal lattice of metals, allowing the beam to be absorbed rather than reflected.

What Can You Do with It?

1. Deep Engraving

You can physically remove material to create 3D relief carvings in brass (think challenge coins) or deep serial numbers in steel that satisfy ATF requirements for gunsmithing.

2. Annealing (Color Marking)

By using low power and high speed, you can heat the surface of stainless steel without vaporizing it. This creates an oxide layer. By controlling the heat, you can create colors (Gold, Blue, Red, Black) on steel without using any ink or paint.

3. Cutting (Thin Metal)

A 30W or 50W Fiber laser can cut through thin sheets of Gold, Silver, and Brass (up to 1mm). This is standard equipment for modern jewelers making custom name necklaces.

Buying Guide: Raycus vs. JPT (MOPA)

When shopping for a Fiber Laser (often looking like a computer tower with a stand), you will see two main "Source" brands:

• Raycus (The Budget Pick): Great for standard engraving and black marking. It has a fixed "Pulse Width." It is the workhorse of the industry.
• JPT MOPA (The Premium Pick): "Master Oscillator Power Amplifier." This technology allows you to change the Pulse Width (frequency). This is required if you want to mark vivid colors on stainless steel or mark plastics without melting them.

Comparison: The Three Technologies

Now that we have finished the series, here is the cheat sheet for your workshop:

Final Safety Warning

Fiber lasers are usually "Class 4" open devices. The 1064nm beam is invisible and passes through the cornea to burn your retina instantly. Unlike a CO2 laser (where clear plastic blocks the beam), standard safety glasses do not work.

You must buy specific 1064nm Rated OD6+ Safety Glasses. If you are running a business, we highly recommend buying a fully enclosed unit to protect your eyes and your pets.