Getting a clean edge on laser cut parts is a top priority for fabricators in any industry. While laser cutting generally creates a cleaner edge than other types of cutting, poorly maintained cutters and environmental factors can create rougher edges and less precise cuts than one might prefer.
With that in mind, anyone using a laser cutter should pay close attention to the factors that go into a clean laser cut to avoid disappointment, frustration, and inaccurate cuts.
The material being cut has a significant influence on how well the laser performs. More specifically, you should be concerned with:
Material Thickness.When using a laser to cut, the heat from the laser creates a molten surface. For example, when cutting metal, the thicker the material, the more likely it is that the molten surface will come in contact with colder sections of the material, creating striations. When we are talking about materials that are only a millimeter or a few millimeters thick, these striations aren’t likely to make much of a difference to the finished product. However, on thicker materials and metals, they will be more obvious if you do not take the time to adjust the tolerances of the laser.
Material Type. It should come as no surprise that the material that you’re cutting is a major determinant in how clean the cut is. Different materials react differently to the laser; a sheet of 3M film, for example, will render a clean, precise cut, while a piece of steel with a high level of carbon will have a rougher edge. To get the cleanest cut, you must fully understand the properties of the material being cut, and adjust the laser accordingly.
Material Quality. Finally, the quality of the material being cut plays a role in the appearance of the cut. The higher quality the material, the cleaner the cut. Surface imperfections can disrupt the focus of the laser, while impurities in metal or other materials can affect the way the material responds to the laser.
Even if you have the most ideal materials for cutting, if your laser cutter is not properly maintained, it’s not going to work well. Among the things to keep in mind:
Cutting lens and cover glass must be kept clean.Depending on the type of laser being used, CO2 or fiber, the cutting surfaces must be kept clean. For a fiber laser, this means keeping the cutting glass completely free of all debris and film to ensure it is clean for cutting. For a CO2 laser, experts recommend using a lens polish to keep the lens free of scratches that can be detrimental to cut quality.
Test the lasers. While the laser nozzle’s position and the focus of the laser won’t make too much difference in how clean the cut is, it can make a difference in the accuracy of your cuts, which affect overall quality of your parts. Many modern machines handle these tasks automatically, but on older laser cutters, you need to perform this maintenance manually in order to ensure clean, accurate cuts.
Use the right laser power and technology. As with any type of manufacturing, using the right tools for the job are important in laser cutting. Using a laser cutter that is inadequate for the job at hand is likely to lead to rougher cuts. Generally speaking, CO2 lasers are best for cutting materials thicker than 8mm, while fiber lasers are ideal for thinner materials.
Certain environmental factors can also affect the way your laser cutters work. The overall air temperature, humidity, air flow, and design of the workspace can affect how well your lasers cut, so it’s important to know your machine and how it works in different environments. A laser cutter in humid south Florida is going to need a different setup than one in the dry southwest, which will be different than one being used in colder New England shops. The bottom line is that to ensure the best laser cuts possible, you need to consider all of the factors that influence a cut, maintain your machine to the best possible specifications, and understand what goes into clean and accurate cuts. Then you can cut with confidence, and know that your parts have been manufactured properly.