What are the differences between YAG and CO2 lasers?

What are the different uses of YAG and CO2 lasers?

Due to the different wavelengths of the laser beams, YAG lasers and CO2 lasers react very differently to different materials. The YAG laser (1064 micron wavelength happens to be ten times that of the CO2 wavelength making it ideal for absorption by most metals, but this small wavelength inhibits its ability to be absorbed by many other materials (wood, acrylic, plastics, fabrics, etc.).

CO2 laser beams are not easily absorbed by metals, but are easily absorbed by many organic materials (such as wood, acrylic, rubber, etc.), but are easily reflected from most metal surfaces. The different wavelengths of the two beams are primarily due to the fact that they will react to different types of materials. There are many other differences between the two lasers. Characteristics such as thermal efficiency, heat transfer, minimum and maximum power output, etc. affect the material opposing the beam.

Does CO2 laser work on any type of metal?

Yes, CO2 works on certain metals in a few different ways. Coated metals include coated brass, anodized aluminum, or any other layer of metal material that a CO2 laser beam can engrave. Even at low power. CO2 lasers are effective at removing paint from most metal surfaces. Painted brass is a popular material to engrave because it can use the high contrast of all the different colors in the engraving process. However, some metal surfaces are coated with very hard paint coatings that are difficult to engrave clearly even with a 120 watt laser. Common products here are ballpoint pens and anything with a powder coating.

Another very popular metal in CO2 is anodized aluminum. The CO2 laser beam turns the anodized coating white when it comes into contact with it and provides good contrast on many different anodized colors. Aluminum protected with a gold coating may not anodize (it can be protected through a chromate conversion process) and will not engrave well.

CO2 laser systems are compatible with painted metals and anodized aluminum due to the high contrast, fast engraving speeds, and low power requirements for a wide variety of projects with these materials.

Stainless Steel Metal Marking

Until recently, marking stainless steel with a low-power CO2 laser has been very difficult. Most are problems. The CO2 energy reflects off the metal surface and is only absorbed in small amounts, producing very weak or non-existent marks. Over the past few years, a number of different companies have introduced products that allow low-powered CO2 lasers to create very black permanent marks on stainless steel. These products are called Laser Marking Material (LMM), commonly known as Cermark or Thermark. LMM is sprayed onto uncoated stainless steel (just like spray painting). You should set the LMM aside to dry for a few minutes before preparing it for engraving.

Laser engraves Cermark as it comes out, it permanently bonds the material to the metal, creating a permanent black mark. After engraving, rinse the metal with water to remove any excess spray. This simple process is commonly used to mark tools, medical devices, and industrial parts with barcodes and serial numbers. LMM can also be used with other metals, but we recommend that you test any other materials you are considering to ensure the marking is acceptable. In our experience, stainless steel LMM is the most predictable metal to use with.

With YAG lasers can you work on any type of non-metallic material?

Unlike CO2 lasers, YAG lasers are only compatible with a limited number of materials. Due to its small wavelength, YAG lasers can mark many different types of metals and plastics, but not nearly as effectively as standard CO2 products (wood, rubber, acrylic, etc.). Typically, you'll only find it in industrial applications. YAG laser, personalization applications are mostly limited to high-volume marking of products such as ballpoint pens.

The reason so many people are excited about LMM is that there are a lot of stainless steel products that need laser marking, and using YAG laser marking is expensive.

YAGLaser Advantages:

Faster than CO2 laser system (set up as vibrator system)

YAG Laser Disadvantages:

Artwork can take a long time to set up, especially when engraving graphics.

Does not work well with organic materials (wood, acrylic, etc.)

Expensive to purchase, high maintenance

CO2 laser benefits:

Works well with materials such as wood, acrylic, plastic

Stainless steel markers (LMM) and most coated metals

Quick setup for each new piece

CO2 laser disadvantages:

Not as fast as YAG (but still engraves at 120 inches per second)

Metals are not engraved, but will leave a mark on some metals