Fiber laser and CO2 systems are commonly used for engraving on metals to mark serial numbers, barcodes, and logos. They are commonly used for laser marking because of their low cost, low maintenance, and long operational life. These two laser engraving systems generate a permanent, high-contrast mark that won’t impact the integrity of the metal.
CO2 Laser Marking
The marking process for the CO2 system requires a special spray-on treatment to be applied to bare metal before engraving. The heat from this process creates a permanent mark on the bare metal that is affordable and fast. These systems can also mark on acrylics, woods, natural stones, and other materials. Another convenience of CO2 systems and fiber systems is that they can be controlled and managed from any Windows-based program.
Coated metals like painted brass and anodized aluminum don’t require a coating and can be marked without pre-treating. CO2 laser marking produces a mark on top of the metal, but doesn’t remove material from the metal, therefore there is no impact on the metal’s strength or tolerance.
See here for more: https://www.needham-coding.com/systems/co2-laser-coding-machines/
Fiber Laser Marking
Fiber lasers are perfect for bare metals like stainless steel, nickel-plated metals, copper, brass, and aluminum. Some engineered plastics like polycarbonates, PEEK, and ABS are also prime materials for fiber laser engraving. However, transparent materials like glass are challenging, as is marking on leather and wood with a fiber laser system.
- Vaporizing the material from the surface
- Ablation removes a top coating from the material – ideal for powder-coated, anodized, and plated metals
- Annealing creates a permanent oxide layer – works well on steel alloys, titanium, and iron
- Polishing is a high-heat process that results in a mirror-like finish – Ideal for any metal
- Foaming melts the material’s surface, producing gas bubbles that cool, leaving behind an elevated result – Ideal for plastics, but is also used on stainless steel
Considerations for Laser Marking on Metals
Different metals have different traits that require special criteria when marking them with a laser system. The laser’s power, frequency, focus, and speed will be adjusted accordingly to achieve the various types of marks like etching, polishing, and annealing.
Fiber lasers often result in brighter markings that CO2 lasers. However, bare aluminum engraving creates less contrast, resulting in hues of gray instead of black. Deep markings used alongside of oxidizers or color fills can create a black etching on aluminum.
Titanium requires adjustments in the laser system to create shades from light gray to dark gray. However, different colors can be achieved by adjusting the laser’s frequency.
There are dual-source systems that provide a way for companies with a low budget or limitations in space to improve their capabilities and versatility. One of the drawbacks of this kind of dual-source system is that when one is in use, the other cannot be used.
The key for each laser engraving business owner is to choose the metal marking system that will suit their needs best. Doing your research, asking fellow engravers, and talking to experts in the industry (sales people and managers) will help if you are just getting started in this market.