Laser Cutting Steel: Preparation, Settings, and Tips

Working with steel can produce an amazing array of products and items of all kinds, from the functional to the decorative. But while one of steel's most prized attributes is its hardness and durability, this can also make it challenging to work with. A laser cutter is one of the best ways to shape steel, but it requires knowledge, precision and care to get the job done correctly.

The Challenge of Laser Cutting Steel

Laser cutters can be deployed to work on a wide range of materials, from paper to steel. Carbon steel ranks among the most difficult to work with for a variety of reasons.

It starts with how strong and durable steel is. In order to cut through it, especially thicker steel objects, you're going to need a high-wattage laser. These machines are large, bulky and powerful, and they require careful preparation and operation to achieve safe and reliable results.

In addition to its strength, steel also poses a challenge because of its reflective properties and high melting point. Stainless steel in particular has an almost mirror-like surface, and if not properly managed, it's easy to end up with uneven or imprecise cuts.

| Related Reading: How to Perfectly Cut Stainless Steel with A Laser Machine

You'll also need to choose and deploy your assist gas properly. Depending on both the type of steel you'll be cutting and the cut quality you're trying to achieve, certain types of gas are more or less appropriate, and selecting the right one is crucial to getting good results.

Finally, an exacting standard of precision is necessary when cutting steel. If your focus, nozzle and settings aren't perfectly aligned before you begin, you'll risk issues like a poor-quality cut, an excess of slag produced during the cutting process, or other problems.

However, all these challenges can be solved with knowledge, preparation and a high level of attention to detail during the process of setting up and executing the cut. If you follow the accepted practices, you'll be able to produce flawless results using a laser to cut steel.

Step-by-Step Guide to Laser Cutting Steel

Using a laser to cut steel is a multi-step process that involves a great deal of preparation. From designing your cut to procuring and preparing materials to setting the designed parameters, you'll need to spend a considerable amount of time before you touch the laser to steel. Then, after making the cut, you'll need to handle the post-processing phase correctly to ensure your finished product is up to standard.

Step 1. Design and File Preparation

The process begins with designing the cut that your laser cutter will eventually perform. This is generally done through software, with multiple programs capable of producing a design that the machine will be able to execute.

Vector-based programs allow you to create your design, with Adobe Illustrator and AutoCAD being two of the most popular. But there are numerous others on the market. These programs will allow you to implement your design visually and then save the results into a file format capable of loading into the laser cutter.

Step 2. Machine and Materials Preparation

When cutting steel, it's crucial that the material itself be as clean as possible. An unclean or impure surface is likely to result in flaws and imprecision while cutting. If the steel is in relatively good shape, you'll be able to prepare it by wiping it with acetone or another degreaser, then using compressed air or a dry wipe as a finishing touch. However, if the steel is in worse shape, you may need a wire brush or a laser cleaning tool.

The next, and perhaps most important step, is acquiring the laser cutting machine you'll use to do the cutting. There are multiple cutters on the market, each with their own advantages and disadvantages in areas like price, accessibility, power/performance, versatility, and other attributes.

xTool MetalFab is an outstanding option, a versatile tool that combines the function of a laser welder, CNC laser cutter and a laser cleaner all in one. Able to handle both carbon and stainless steel, in addition to a range of other metals and materials, the MetalFab would be able to accomplish any steel cutting-related task you might require.

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When cutting steel, you'll also need to procure assist gas. The two primary functions of assist gas are to eject molten material from the cut area and to cool the steel after cutting, reducing the risk of distortion or warping. The three main types of assist gas are:

• Nitrogen is well-suited to stainless steel in particular, and facilitates an especially high-quality cut.
• Oxygen has the ability to increase the heat level of the cut, making it the best choice when cutting denser, thicker objects.
• Compressed air, a combination of oxygen and nitrogen, is a more economical choice and works well when cutting less substantial objects.

Step 3. Laser Cutting Parameters Configuration

Next, you'll need to configure your laser cutting machine to ensure a clean and error-free cut. You'll have already selected your assist gas based on the type of steel and the thickness of your object. It's necessary to specify the pressure with which that gas will be deployed.

In addition, you'll need to choose a power and cutting speed that's appropriate to the type of cut you're making and the material you're cutting through. As a general rule, thicker materials require a slower cutting speed, while you can go more quickly through thinner objects.

It's highly advisable to make a few test cuts once you've entered all your parameters to ensure that the results you get are in line with your expectations. After that, you're ready to actually make the cut.

Step 4. Execution and Optimization

Once you've done all the hard work of preparing your materials and entering your specs, it's time for the laser cutting machine to take over. Once you activate it, the machine will apply the laser and execute the cut you've specified. Once the material has cooled enough to be safe, you can inspect to confirm that the cut is to your liking.

Step 5. Post-Processing

After the cut is finished, there are a variety of post-processing steps you may want to engage in. Deburring and sanding can help smooth away some of the rough edges, and you may want to polish, paint or anodize the object's surface. You may also now want to weld your newly cut steel object to another object.

Recommended Parameter Settings Laser Cutting Carbon Steel

Fortunately, if you are using MetalFab, there are already over 108 of settings preset in the machine’s software, based on the type of steel you're cutting and the thickness of your material.

While you want to use the exact specifications for your specific thickness and material, here are some general rules.

As a general rule, greater power means you can increase the cutting speed. But when cutting particularly thick objects, you'll want to select lower cutting speeds regardless of power.

Causes and Solutions for Common Steel Cutting Problems

Burrs, or jagged edges, can sometimes occur when cutting with a laser. These usually result from an error in selecting parameters or adjusting the laser's focus. Be sure to double-check your parameters, and also test the laser before using it on your actual object.

Poor cut quality can also result from incorrect parameter settings, but can also be the result of unclean or uneven material surface. In addition to checking parameters and testing, be absolutely certain that your steel is in pristine condition.

Sometimes, the edges of a cut can end up discolored. This often stems from oxidation during the cut, and this is one reason why nitrogen is often preferred as an assist gas. However, in some cases, you may be able to simply clean the discoloration off during post-processing.

In more extreme cases, your laser may not cut fully through the steel. In almost all cases, this is an issue with the parameters you've selected. Either increasing the power, decreasing the cutting speed, or a combination of the two will generally solve this issue.

Tips for Perfect Cutting

When it comes to cutting steel with a laser, expertise comes with experience. As you do it more, you'll learn through trial and error how to execute perfect cuts nearly every time. But there are a number of tips that will skip you past much of the growing pains many newcomers experience.

• In most cases, the preparation work you do will lead to the success or failure of your project before you even start cutting. Don't skip steps, take your time, and double-check everything.
• Cleanliness ensures precision. Make sure your laser cutting machine is kept clean, as well as the material you're cutting and even the surrounding environment.
• Once you've created your design and made parameter decisions, the last, most important thing is to make sure your focus is precisely aligned. The exact placement depends on the material and placement.
• While choosing too high a cutting speed can cause problems, too slow has issues too. A too-slow speed can keep heat in a cutting zone for too long, leading to distortion.
• When in doubt, test before making your real cut. If you've got excess steel to spare, it's always a good idea to test everything before your real cut.

By following these guidelines, you'll quickly master the basics and begin to produce outstanding laser-cut steel objects. A new world of design and production opportunities opens up for you once you've mastered the art of cutting steel with a laser.