How to Make a Laser Engraving File

Most failed laser jobs are not settings problems. They are file problems, and they fail in a handful of predictable ways: text that turned into the wrong font, a shape that engraved as an outline instead of filling, a cut line that ran twice, a photo that came out as mush.

All of those are fixed before the file ever reaches the machine. This covers how to build a file that works the first time.

The Three Things a Laser Does

Before file formats, the concept that makes everything else make sense. A laser performs three operations, and your file has to tell it which one applies where.

Cutting. The beam follows a line at high power and low speed, going all the way through the material. The file supplies a vector path.

Line engraving, or scoring. The beam follows the same kind of vector path at lower power, marking the surface without cutting through. Fast, and the right choice for outlines and fine linework.

Fill, or raster engraving. The head sweeps back and forth like an inkjet printer, building up an area of engraving line by line. This is what produces solid blocks, shaded areas and photographs.

Vector and Raster

Vector files store paths, meaning mathematical descriptions of lines and curves. They scale to any size without losing quality, and they are the only thing a laser can cut, because the machine needs a path to follow. SVG, AI, DXF and PDF are vector formats.

Raster files store pixels. They cannot be cut, only filled, and their quality is fixed at the resolution they were created at. PNG, JPG and BMP are raster formats, and they are what you use for photographs and complex shaded artwork.

Most real jobs use both. A sign might have a photograph engraved as raster, a company name line-engraved as vector, and an outline cut as vector, all in one file on three different layers.

Which File Format to Use

If in doubt, use SVG. It handles everything except photographs, imports predictably into every laser control program, and is produced by free software as readily as by Adobe.

Software You Need

You need a design program to build the artwork. Adobe Illustrator and CorelDRAW are the commercial standards. Inkscape is free, fully capable and exports native SVG, which makes it the obvious starting point if you are not already in the Adobe ecosystem. Affinity Designer is a one-off purchase with no subscription.

A laser control program to drive the machine. LightBurn is the standard across the industry and runs every Thunder Laser gantry machine. It also has enough drawing capability that simple jobs can be built in it directly, without a separate design program at all.

If you are still choosing, our laser cutting software guide compares the main options. You can also do everything in LightBurn for simple work: text, basic shapes, importing and arranging. The separate design program matters once artwork gets complex, or when you are receiving files from clients.

Building the File, Step by Step

1. Set the document to final size. Make the artboard match the material, or at least the finished piece. Designing at the wrong size and scaling later is where raster quality and stroke widths go wrong.

2. Build or import the artwork. Vector shapes and text for anything to be cut or line engraved. A high-resolution raster image for anything photographic.

3. Separate the operations onto layers. One layer for cutting, one for line engraving, one for fill. In LightBurn these are colors, and each color carries its own speed, power and mode.

4. Set cut lines to hairline. A stroke width of 0.001 inches, often called hairline. More on why below.

5. Convert all text to paths. Before saving. Every time.

6. Check for open paths and duplicates. Anything you intend to fill must be a closed shape, and no two lines should sit on top of each other.

7. Export as SVG. Then import into your laser software, assign settings per layer, and run a preview before you run the job.

Preparing Vector Files Properly

Convert Text to Paths

This is the single most common file failure and the easiest to prevent.

Text in a vector file is stored as characters plus a font reference. If the computer opening the file does not have that exact font installed, it substitutes another one, usually without warning. Your carefully spaced lettering becomes something else, and you may not notice until the job is cut.

Converting text to paths turns the letters into shapes. In Illustrator it is Create Outlines, in Inkscape it is Object to Path, in CorelDRAW it is Convert to Curves. Do it on a copy, because once converted the text is no longer editable as text.

Hairline Strokes for Cutting

A stroke width of 0.001 inches tells the software this line is a path to follow rather than a shape with thickness. Set a cut line to 2pt and some programs will interpret it as a long thin rectangle and engrave both edges of it instead of cutting down the middle.

One source of confusion worth clearing up: advice to avoid very thin lines applies to engraving, not cutting. A hairline stroke on an engrave layer may be too fine to register, but on a cut layer a hairline is exactly what you want, because the machine is following a path rather than filling a shape. The layer decides which rule applies.

The beam has its own width regardless. A CO2 beam is roughly 0.1 to 0.3mm wide at focus, and that kerf is removed from the material. For parts that have to fit together, account for it in the design rather than in the stroke width.

Close Every Path You Want Filled

A fill operation works by scanning across a shape and turning the beam on inside it. If the outline does not close, the software cannot determine what is inside, so it either fills nothing, outlines instead, or fills in an unpredictable way.

This is the cause of the 'it only did the outline' problem. LightBurn and most other programs can highlight open paths, and closing them is usually a matter of selecting two endpoints and joining them.

Remove Duplicate and Overlapping Lines

If two rectangles share an edge, or a shape has been pasted twice, the laser will run that line twice. On an engrave that means a doubled, darker mark. On a cut it means the beam passing a second time through an already-open kerf, which wastes time, chars the edge, and on thin flammable material is a genuine fire risk.

Most laser software has a duplicate removal tool. Run it before every job. LightBurn also has an edit function that welds overlapping shapes into a single outline, which is usually what you actually want.

Simplify Traced Artwork

Auto-traced vectors frequently carry thousands of nodes where a few dozen would do. The machine slows at every node, so a heavily noded file engraves slowly and can produce visible stuttering on curves. Use a simplify or reduce nodes function after tracing.

Preparing Raster Files

Resolution has to be right at final size. Aim for around 300 DPI at the size the image will actually be engraved, and our guide to what DPI means in laser engraving covers how the setting behaves on the machine. A web image that looks sharp on screen is often 72 DPI, and enlarging it adds pixels without adding detail. The engraving will look exactly as soft as the source.

Increase contrast before importing. Laser engraving has a narrower tonal range than a printed photograph, so midtones compress. Pushing contrast and slightly brightening the image before import usually produces a better result than adjusting settings afterwards.

Choose the right dithering. Laser software converts greyscale into dot patterns because the beam is either on or off. Jarvis and Stucki suit photographs; Threshold suits pure black and white line art; Newsprint has a halftone look. The wrong choice makes a good photo look muddy.

Convert to greyscale yourself. Doing the conversion in an image editor gives you control over how colors map to brightness. Letting the laser software do it automatically rarely produces the best tonal separation.

Converting an Image to Vector

Sometimes you have a logo as a JPG and need to cut it. That means tracing, which converts pixels into paths.

The basic workflow in LightBurn is to import the image, select it, then Tools and Trace Image. Adjust the threshold until the preview captures the shapes you want, then trace. Ungroup the result, because it imports as a single grouped object.

If the trace comes out messy, clean the input first. Open the image in an editor, convert it to pure black and white with no greys, remove background noise, and save as BMP. Re-import that and trace it. Tracing works on contrast, so a cleaner input produces a dramatically cleaner result than fighting the trace settings.

Tracing does not work on photographs. A portrait traced to vector becomes an unrecognizable mess of blobs. Photographs are raster work; trace only logos, silhouettes and line art.

Then simplify. Reduce the node count before using the traced result, and check that outlines closed properly if you intend to fill them.

Layers, Colors and Order

In LightBurn and most laser software, color is the layer system. Each color in your file becomes a separate layer with its own speed, power and mode.

Assign a distinct color to each operation. Black for fill engraving, blue for scoring, red for cutting is a common convention, and the specific colors do not matter as long as you are consistent and they differ.

Order matters, and the rule is engrave first, cut last. Once a part is cut free it can shift slightly, and anything engraved after that will be misaligned. Laser software lets you set the order of operations; check it rather than assuming.

Cut inner shapes before outer ones. If you cut the outline first, the piece drops away and the interior cuts land on a part that has moved. Most software handles this automatically, but it is worth confirming on a complex file.

The Mistakes That Ruin Jobs

Text not converted to paths. Silent font substitution. The most common of all.

Thick strokes on cut lines. Engraves both edges instead of cutting the middle.

Open paths on fill layers. Outlines instead of filled shapes.

Duplicate lines. Double cutting, charred edges, wasted time.

Low-resolution raster. Soft, muddy engraving that no setting rescues.

Designing at the wrong size. Scaling afterwards degrades raster detail and leaves stroke widths wrong.

Everything on one layer. No way to give cutting and engraving different settings.

Skipping the preview. Laser software will show you the exact path before it runs. Thirty seconds spent there catches almost everything above.

The Five-Second Checklist

Before any file goes to the machine: text converted to paths, cut lines at hairline, paths closed on anything being filled, duplicates removed, and operations separated onto layers. That is the whole thing, and it catches the overwhelming majority of failed jobs.

Then run the preview. Every laser control program will show you the exact path the head will take before it takes it, and reading that for thirty seconds is the cheapest quality control available.

Once the file is right, the settings are the easy part. Our free materials library has tested speed and power across 22 materials, as a LightBurn file you can import directly. If you would rather watch a machine run your file before buying one, book a demo.