Metal Laser Cutting Tips

steel after parts have been laser cut

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Laser cutting is a 2D technology, as light travels in only one direction at a time.

This requires a very simplified and deconstructed approach to production. Laser cutting requires a digital 2D vector drawing. This can be thought of as the stencil or route that the laser will follow as it cuts the metal.

There are a lot of 2D vector drawing programs out there, ranging from online applications to professional, CAD engineering software. Regardless of the program you use to create your file, the key is being able to export the file in a format suitable for production.

At Black Lab, we’re pleased to provide custom laser file preparation and engineering services. But if you’re planning on producing your own file for laser cutting, here are a few tips to keep in mind:

  1. Close your design’s edges

The laser cuts along outlines in the metal. As such, everywhere that you want to have open or free from metal needs to be fully surrounding in a complete, closed contour. For instance, if you want a circle laser cut out of a sheet of metal, make sure the arc in your file is a fully connected circle. Even tiny “breaks” in lines can result in the would-be cutout remaining attached to the sheet metal as an accidental tab.

2. Mind your metal tabs and notches

Laser cutting relies heavily on tabs and notches. Getting them right maintains the structural integrity of the metal sheet or plate while the product is being produced.

For Metal Notches: As a rule of thumb, the minimum width of a notch should be at least 1 mm or the material’s thickness, whichever is greater. The length should be no more than five times its width. The distance between notches should be at least 3 mm.

For Metal Tabs: Tabs have to be at least 3 mm thick or two times the material’s thickness, whichever is greater. The length should always be less than five times the width. Tabs should be spaced either a minimum of 1 mm from each other or equivalent to the material’s thickness, whichever is greater.

3. Identify line thicknesses and depths

When submitting your file clarify and distinguish what each style of line means. Laser cutting is able to do everything from hairline deep cuts to wide etching. Make sure that your file distinguishes and that you clearly communicate what you intend to cut and what you intend to etch, and at what widths or depths you intend to do either.

4. Plan for precise holes and laser accordingly

If you need holes with tight tolerances, a best practice is to use the laser cutter to pierce and etch the specific location for the holes. Then, have the holes drilled directly with a bit. For threaded holes, this is the best way to get an accurate result. Lasers heat and melt steel, but drilling into cold steel will help ensure a flawless final product. A pierced guide hole should naturally be smaller in diameter than the intended final hole.

5. Decide on rounded corner fillets or sharp angles

Sheet metal parts often have sharp corners. For added safety, fillets (rounded corners) can be added to the otherwise sharp corners. It’s generally recommended that fillets are at least half the thickness of the material. Whether you want safer corners with fillets or sharp corners, make sure they’re marked in your file or at least discussed with your technician at Black Lab.

6. Correctly lay out your file for multiple parts

When cutting multiple parts on the same sheet of metal, it’s often best to leave a distance of at least the material’s thickness between them. If you put parts too close to each other or cut very thin features, you risk burning away material between two cutting lines. It’s also advised to outline each piece as a whole, instead of trying to “share” cuts by using lines between two pieces.

7. Get the metal laser cutting file format right

At Black Lab, we work primarily with .dxf or .dwg files. These vector files are generated by professional programs such as AutoCAD, SolidWorks, Inventor, Draftsight, and Adobe Illustrator, but there are an endless number of software programs and online applications that can convert PDF, .eps, .svg, and other file formats into .dxf or .dwg files. If you have your .dxf or .dwg file ready to go, great! If not, we’re happy to help you create one from scratch or by converting existing data.

Contact our team for assistance.

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