Dec 3, 2020 8:24:00 AM Eric Johnson
Aluminum is one of the more challenging materials to laser cut. That's not to say it can't be done, but it does require a bit of expertise. Among other things, it can be difficult to create a clean-cut edge when laser processing aluminum. In this post, I’m going to cover some of the properties that make aluminum a challenging material for laser processing and provide a few tips to help your laser cutting efforts be more successful.
Laser Cutting Aluminum
Whether you're laser etching aluminum or cutting thin aluminum sheets, the tips and information outlined here will help you be successful with this product. The first thing to understand is what unique characteristics aluminum brings to laser processing.
Why is aluminum more difficult to cut? Aluminum has some properties that react differently to laser beams. These properties have to do with its reflectivity, molecular structure and thermal conductivity.
Difficulties of Aluminum and Laser Processing
When you project light onto a reflective material, it bounces back or scatters. So when the light of a laser beam makes contact with aluminum, the tendency is for it to bounce or scatter as well. This can make laser cutting difficult.
Solid and stable molecular structures are easier to cut through than softer ones. Because aluminum’s molecular structure is more malleable, the laser beam is not as effective at piercing through it and creating clean cuts.
Finally, aluminum is a heat conductive material. As such, it quickly absorbs heat, which is needed for clean cutting. Also, when you dissipate the heat it makes smooth laser processing difficult.
All of these reasons are why laser cutting aluminum is difficult. But just because something is difficult doesn’t mean we can’t do it. Over the years, we’ve fine-tuned our aluminum cutting capabilities to make it an easy and effective process.
How to Cut Aluminum sheet
While it is reflective, soft and thermally conductive, aluminum can still be cut with a CO2 or fiber laser. High-speed laser beams make it possible to cut various alloys of aluminum, including aerospace and marine-grade aluminum alloys.
Using a Metal Cutting Head
When cutting aluminum with a CO2 laser, we're using a metal cutting head, which is a different assembly than the one used when cutting non-metal materials like plastic or foam.
The metal cutting head assembly has a protective window for spark reflection and a variable/adjustable focus knob. These features make cutting aluminum sheet much more effective. It eliminates the issue of finding the right focus position and setting the perfect height.
Creating a Clean-Cut Aluminum Edge
In order to get a clean-cut edge with aluminum cutting, you want to focus on two things: high pressure and gas assist. These two combined will effectively eject any molten material quickly, preventing the buildup of a rough edge. With aluminum, the faster you cut, the smoother the edge will be. That’s also why higher wattage lasers will perform better when cutting aluminum. They allow you to push the kerf line faster.
Unlike other options, like routers or CNC cutters, laser cutting aluminum is a fast, efficient process. It also allows for no contact cutting, so the only thing touching the material during processing is light. There is absolutely no need to clamp down or otherwise secure the material. Not only does this save you time, but it prevents any impressions or damage making its way into the material.
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