A CNC laser cutting machine slices effortlessly through sheet and plate to produce whatever 2D contoured form you need. But the fact that they’re fast and sexy doesn’t necessarily mean one is right for your shop. And if a laser cutting machine is the right choice, do you go for fiber or CO2 technology?

Here’s some advice on what to consider before cutting the purchase order.

Laser Cutting Machine Pros and Cons

In their favor, laser machines can cut material 1” thick or thicker, quickly and accurately, (depending on the power available.) In addition, they don’t need any tooling, which makes them extremely versatile.

However, they do have consumables – the assist gases – which, depending on the type of gas and how much you use, can become a significant expense. There’s also the question of edge quality, (which assists gasses influence.)

Edge quality relates to:

  • A heat affected zone where the material properties may be changed
  • On thicker material the laser can wander and drag a little, giving rise to striations that may need cleaning up.

Alternatives to a CNC laser cutting machine are a plasma cutter, (good for thick material,) and a CNC punch press, (good for thinner sheet.) The punch press needs tooling but doesn’t use assist gases and can result in better edge quality.

Choosing Your Laser Technology

There was a time when all laser cutting machines used the same CO2 technology to produce an infrared beam with a 10.6-micron wavelength. In 2008 fiber lasers came onto the metal cutting scene with a 1-micron wavelength. Metals absorb that wavelength better and so heat up faster. As a result, fiber lasers now dominate the market. If you’re choosing a laser cutting machine that’s probably what you’ll go with, but you should know the pros and cons.

Fiber lasers:

  • Cut brass, copper and aluminum in addition to carbon and stainless steel
  • Cut material less than ¼” thick faster than CO2
  • Need less maintenance than CO2
  • Use less energy than CO2

CO2 lasers:

  • Cut thick material faster than a fiber laser
  • Produce better edge quality on thick material

Laser Power

You’ll see laser cutting machines rated from 1 or 2 kW all the way up to 10 kW or more. In general terms, more power means higher cutting speeds and the ability to cut thicker material. However, a more powerful laser costs more, so there’s a trade-off to be made.

Assist Gases

The commonly used assist gases are oxygen, nitrogen, and shop air. Some laser cutting specialists will also use argon and oxygen-nitrogen mixtures. The main purpose of the assist gas is to blow away the melted material so it doesn’t solidify as the laser moves. In addition, nitrogen and argon can prevent oxidation while oxygen creates an exothermic reaction that raises the cutting temperature.

Laser Selection

The most important point to consider when choosing a CNC laser cutting machine, what do you want to do with it? The answer to that will guide you towards the most appropriate laser technology and the power you need.

For more advice on buying laser cutting machines or any other kind of manufacturing equipment, The Equipment Hub is ready to help. Contact us and let’s talk.

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