Superhero movies are filled with characters who’ve been granted great power. Some, like Spider-Man, use it responsibly, others, (looking at you, Thanos,) not so much. Well, we won’t claim to be superheroes but we are about to gain a lot more power. In our case it comes, not from Infinity Stones or radioactive spiders, but an 8kW fiber laser cutting machine.
In case you’re not familiar with laser cutting machines, yes 8kW is a lot of power. It’s a big step up from the lasers we have today. Here’s why we’re so excited about bringing this new machine into our shop.
Cutting Metal With Light
Laser cutting is about focusing a beam of intense, coherent light down to a spot that’s hot enough to melt metal. Then it’s used to cut a thin line through that metal, either by moving a sheet under the beam or moving the beam over the sheet.
Traditionally, meaning over the last 20 years or so, laser cutting meant using light from a CO2 laser. A few years ago a new technology appeared that offered some advantages. This was the fiber laser, and in “Advantage Fiber VS CO2 in the Laser Cutting Battle,” we explained what it brings to the party. At the time we said our next laser cutter would likely be a fiber machine. Well, that time has come.
What’s Special About Fiber Lasers?
The big advance over CO2 lasers is that the light they put out is a much shorter wavelength. A CO2 laser emits light with a wavelength of 10.6 microns while that from a fiber laser is 1 micron. (Physics nerds will point out that both are in the infrared part of the spectrum and are therefore invisible to human eyes.)
Now, what does this have to do with cutting metal? Two things:
- A shorter wavelength can be focused into a smaller spot. That means more energy per square millimeter, so faster heating, and a smaller kerf.
- Many metals reflect the long-wavelength light but do a much better job of absorbing the shorter wavelength from the fiber laser. That means less of the fiber laser light is reflected and more goes into heating and melting metal.
So, bottom line: a fiber laser provides a lot more energy to cut with. But most laser machines don’t cut with light alone.
High Power Fiber and Assist Gases
Years ago it was found that shielding the laser beam in oxygen increases the cutting temperature. Plus, a high-velocity jet would blow out the melted dross rather than leaving it hanging on the bottom of the sheet or plate.
This meant that by using oxygen for assistance you could cut faster. However, oxygen also has a habit of causing oxidation of the cut edge. The solution to that is to replace oxygen with nitrogen. It lowers the cutting speed but leaves a clean edge that needs little-to-no clean-up before sending the sheet for powder coating or welding.
Then people started experimenting with blends of oxygen and nitrogen. Pretty quickly someone realized that air is 20% oxygen and 80% nitrogen and so the idea of air-assisted laser cutting was born.
Air assistance is particularly useful when you have a high-power laser that doesn’t need a lot of extra heat from oxygen. And like using nitrogen, it yields a very clean edge that’s ready for coating or welding. This is why our new laser is equipped with high-pressure air assist, (and can also run oxygen or nitrogen as needed.)
So much for the science and the machine specifications. Let’s turn to the advantages high power fiber lasers offer fabricators like us.
Top 5 Advantages of a High Power Laser Cutting Machine
When we were looking for ways to enhance our laser cutting capabilities we made a list of the advantages we could see from going to a fiber machine. It turned out to be a long list. To avoid boring you with detail, here, in reverse order, are the top 5 advantages we identified.
5. Better material utilization and tighter nesting, thanks to narrower kerf and less distortion due to workpiece expansion.
4. Cut thicker sheet and plate material. With this laser, we can cut mild steel up to 0.312” thick and stainless and aluminum up to 1” thick.
3. Faster piercing and cutting. Higher power and a smaller spot size mean a fiber laser “punches” through in less time. On a job where there are a lot of holes to cut that can lead to big time savings. Plus, faster melting allows higher traverse speeds. That’s even more time saved.
2. Cut reflective materials like aluminum and copper. Cutting these with a CO2 laser meant going very slowly because they reflected most of the laser energy. The shorter wavelength of fiber means we can cut these at a speed that’s high enough to be useful.
1. Better cut edge quality. This is primarily a result of higher power and air assist, but laser beam geometry and workpiece thermal conductivity contribute too. The thinner beam keeps the energy more tightly focused, and that means a sharper edge. In addition, by putting less heat into the metal there’s less distortion.
With Great (Metal Cutting) Power Comes …
Many fabrication projects start with pieces of sheet or plate being cut to size and shape. From there they usually go to welding and very often, powder coating. Laser cutting is an efficient way for us to produce those blanks. Our fiber laser is a step up from the lasers already in our shop and will let us cut even more efficiently. That’s because of increased speed and thickness capabilities and also as a result of the better edge quality it will yield.
As you can probably tell, we’re excited about having more power in our laser cutting department. Trust us, though, we are going to use that power responsibly. If you’d like to find out how, talk to us about your next fabrication project. We’re always happy to help.