How to Prepare Files for Laser Cutting

You've designed something beautiful. Maybe it's a box with finger joints, a decorative panel for a friend's wedding, or a prototype enclosure for that electronics project you've been putting off. You export the file, load it into your laser software, and hit start. The machine cuts right through your tabs. The pieces don't fit together. The engraving is blurry. And the whole thing is 3mm too small because nobody told you about kerf.

File preparation is the unglamorous bridge between "I designed a thing" and "this thing actually works." Most laser cutting failures aren't caused by bad settings or bad materials. They're caused by bad files. Wrong format, missing layers, overlapping paths, no kerf compensation, text that isn't outlined. The machine does exactly what the file tells it to do, and the file was wrong.

This guide covers the entire file preparation workflow from design to cut. Not the design itself (that's a creative problem, and you're on your own there), but everything that happens between finishing your design and pressing Start.

Why File Preparation Matters More Than You Think

Your laser is a very precise, very obedient machine. It will cut exactly where your file says to cut, at exactly the speed and power your settings dictate. It doesn't question whether those paths make sense. It doesn't fix overlapping lines. It doesn't adjust for the width of its own beam. It just goes.

This is both the beauty and the danger of laser cutting. A well-prepared file produces perfect results on the first try. A poorly prepared file wastes material, wastes time, and can even damage your machine (running the same path twice on thin material, for instance, or trying to cut through a section where paths overlap and create excessive heat).

Here's what proper file preparation gets you:

• Parts that fit. Kerf compensation means your tabs, slots, and interlocking joints actually work.
• Clean separation of operations. Cut lines cut. Engrave areas engrave. Score lines score. Nothing gets confused.
• No wasted passes. Duplicate paths, hidden objects, and stacked lines all cause your laser to run the same area twice. That's wasted time at best and scorched material at worst.
• Predictable results. When your file is right, the same file produces the same result every time, on every piece of material.

If you're new to laser work entirely, our laser engraving beginner's guide covers machine setup, safety, and your first test engrave. This post assumes you have a working laser and basic familiarity with your software. We're focusing on the file side of things.

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File Formats for Laser Cutting

Not all file formats are created equal, and your laser software has opinions about which ones it prefers. If you want the full breakdown of every maker file format, our file format guide covers the entire landscape. Here, we're focusing specifically on what works for laser cutting and why.

SVG (Scalable Vector Graphics)

SVG is the most versatile format for laser work. It stores vector paths (the math that describes your shapes), along with color information, stroke widths, layer names, and other metadata. LightBurn reads SVGs natively. Most design tools export them. They're human-readable XML, which means you can even edit them in a text editor if you're feeling brave.

Best for: Most laser workflows, especially if you use LightBurn. SVG preserves color information, which maps directly to LightBurn's layer system.

Watch out for: Embedded raster images inside SVGs (they look like vectors but aren't), live text that isn't converted to outlines, and units that don't match your workspace.

DXF (Drawing Exchange Format)

DXF is the CAD world's standard exchange format. It describes pure geometry: lines, arcs, polylines, splines. No fills, no colors (well, technically it has layer colors, but they work differently than SVG colors). It's the format that industrial laser controllers have accepted for decades.

Best for: Machines running RDWorks, older Chinese controllers, or any workflow where SVG imports are unreliable. Also preferred if you're coming from CAD software like AutoCAD or Fusion 360.

Watch out for: DXF version compatibility. Older controllers may only accept R12 or R14 format DXF files. If your import looks wrong, try re-exporting as an older DXF version.

If your laser software requires DXF and your design is in SVG, our SVG to DXF conversion guide walks through the process and the common pitfalls.

AI (Adobe Illustrator)

Adobe Illustrator's native format. Some Chinese laser controllers and CorelLASER accept AI files directly. If you're designing in Illustrator, you can often skip the SVG/DXF export entirely.

Best for: Workflows that start and end in the Adobe ecosystem, or machines with controllers that specifically list AI as a supported format.

Watch out for: AI files with effects, gradients, or transparency. Your laser controller will either ignore or misinterpret these. Flatten everything before saving.

PDF (Portable Document Format)

PDF can contain vector paths, raster images, or both. LightBurn can import vector PDFs and extract the cut paths. Glowforge uses PDF as its primary import format.

Best for: Glowforge users, or when someone sends you a design as a PDF and you need to extract the vectors without opening Illustrator.

Watch out for: PDFs that contain raster images instead of actual vectors. The file extension doesn't tell you what's inside. If your import looks blocky or pixelated, the paths aren't vectors.

PNG and JPG (Raster Images)

Raster images are grids of pixels. They don't contain cut paths. Your laser software can use them for engraving (converting the pixel data to a burn pattern), but they can't be used for cutting.

Best for: Photo engraving, raster fill engraving of images or graphics. If you're engraving a photo onto wood, a high-resolution PNG or JPG is what you want.

Not for: Cutting. Ever. If you need cut lines from a raster image, you need to vectorize it first.

Quick Format Comparison for Laser Cutting

Vector vs Raster: When to Use Each

This distinction drives every decision in laser file preparation, so let's be crystal clear about it.

Vector operations use the laser like a pen. The head follows a path, tracing lines, curves, and shapes. The laser fires continuously along that path. This is what happens when you cut, score, or do vector engraving (outlining shapes with the laser).

Raster operations use the laser like a printer. The head sweeps back and forth in horizontal lines, firing in short pulses to create dots. Dense dots make dark areas, sparse dots make light areas. This is how photos, fills, and shading get engraved.

Here's when to use each:

Most real projects use both. A decorative sign might have vector cut lines for the outline, vector engraving for text outlines, and raster engraving for filled graphics. Your laser software handles both, but you need to set them up on separate layers with different settings. Which brings us to the most important part of file preparation.

Setting Up Cut vs Engrave Layers

This is where beginners trip up most often. Your design has elements that need to be cut, elements that need to be engraved, and maybe elements that need to be scored. Each operation needs different power/speed settings. The way you tell your laser software which operation to use on which element is through layers, and layers are mapped by color.

How Color Mapping Works

In LightBurn (and most laser software), every color in your design maps to a separate layer. Each layer has its own speed, power, and operation type. So if you draw your cut lines in red, your engrave areas in blue, and your score lines in green, LightBurn creates three layers and you can assign different settings to each.

This is why SVG is the preferred format for laser work. It preserves color information through the import, so your layers arrive already separated.

Here's a common color convention (not a standard, but widely used):

Setting Up Layers in LightBurn

When you import a multi-color SVG or DXF into LightBurn, the Cuts/Layers panel automatically creates entries for each color it finds. Here's how to configure them:

1. Import your file. Each unique color becomes a layer in the Cuts/Layers panel on the right side.

2. Set the operation type for each layer:

   • Line = vector cutting/scoring. The laser traces the path.
   • Fill = raster engraving. The laser sweeps back and forth filling enclosed areas.
   • Fill+Line = raster engrave the interior, then trace the outline.
   • Offset Fill = engraves from the outside in (good for certain effects).

3. Set power and speed for each layer. Cut layers get high power and low speed. Engrave layers get medium power and high speed. Score layers get low power.

4. Set the layer order. LightBurn processes layers from top to bottom. Always engrave first, score second, cut last. If you cut first, the pieces shift on the bed and your engraving won't align.

Setting Up Layers in LaserGRBL

LaserGRBL handles layers differently than LightBurn. It's more image-focused and doesn't have the same multi-layer color mapping. For pure vector cutting, most LaserGRBL users work with single-color files and run separate jobs for different operations.

If you need to cut and engrave in the same project with LaserGRBL:

1. Separate your design into individual files. One file for the engrave elements, one for the cut lines.
2. Run the engrave file first with appropriate raster settings.
3. Run the cut file second without moving the material or the machine's origin.
4. Use the same origin point for both files so everything aligns.

This is one of the big reasons LightBurn is worth the $60 upgrade. Multi-layer processing in a single job saves significant time and eliminates alignment errors between operations.

Power, Speed, and Layer Settings Explained

Every layer in your design needs three core settings: power, speed, and the operation type. Getting these right is the difference between a clean cut and a charred mess. For material-specific numbers, our laser settings for wood cheat sheet has starting points for 11 wood species.

Power (%)

How hard the laser fires. 100% is full blast. For cutting, you usually want high power (80-100%). For engraving, you back off to avoid charring (40-70% depending on material). For scoring, even less (20-40%).

Speed (mm/min or mm/s)

How fast the laser head moves. Slower speed means more energy deposited per unit length, which means deeper cuts and darker engraves. Faster speed means lighter results.

LightBurn uses mm/s by default. LaserGRBL uses mm/min. Don't mix them up, or your "slow" cut at 300 will either crawl at 5mm/s or race at 300mm/s depending on which unit your software expects.

Passes

Number of times the laser repeats the same path. For cutting, multiple passes at lower power often produce cleaner results than a single pass at full power. The first pass vaporizes the surface, and subsequent passes cut deeper without as much charring.

For engraving, you almost never need multiple passes unless you're going for a very deep engrave on hard material.

DPI / LPI (Raster Engraving Only)

DPI (dots per inch) or LPI (lines per inch) controls the resolution of raster engraving. Higher DPI means finer detail but slower processing.

For most wood engraving, 254-300 DPI is the sweet spot. Going higher than 500 DPI rarely produces visible improvement because the natural grain of the wood limits the effective resolution anyway.

Kerf Compensation: The Most Overlooked Step

Kerf is the width of material removed by the laser beam. When your laser cuts a line, it doesn't cut an infinitely thin path. It vaporizes a small strip of material, typically 0.1mm to 0.3mm wide depending on your laser type, focus, and settings.

This sounds tiny, but it adds up. If you're cutting a box with finger joints and each tab has kerf error on both sides, a 10-tab joint can be off by 2-3mm total. That's the difference between a snug press-fit and a box that needs glue and clamps to stay together.

How Kerf Works

Imagine cutting a 50mm square out of a sheet of wood. If your laser's kerf is 0.2mm, the actual piece that falls out is 49.8mm wide. The hole left in the sheet is 50.2mm wide. That's because the laser beam is centered on your cut line, removing 0.1mm on each side.

For single pieces, this usually doesn't matter. But for anything that fits together (boxes, puzzles, inlays, mechanical parts), kerf makes the difference between success and failure.

Measuring Your Kerf

Here's how to measure your laser's kerf for a specific material and setting combination:

1. Cut a straight line in your material using your intended cut settings.
2. Measure the width of the gap with calipers. This is your kerf width.

Or, for more precision:

1. Cut a rectangle with a known width (say, 50mm).
2. Measure the actual piece that falls out.
3. Kerf = (designed width - actual width) / 2

For example: if you design a 50mm square and the cut piece measures 49.76mm, your kerf is (50 - 49.76) / 2 = 0.12mm.

Applying Kerf Compensation

There are two approaches to kerf compensation:

Method 1: Adjust in your design software. Offset your cut lines inward (for pieces that need to be bigger) or outward (for holes that need to be smaller) by half the kerf width. In Inkscape, use Path > Inset/Outset. In Illustrator, use Object > Path > Offset Path.

Method 2: Use your laser software's kerf offset. LightBurn has a built-in kerf offset setting in the layer properties. Set it to half your measured kerf width and LightBurn automatically adjusts the cut path. This is the easier approach because you don't need to modify your original design.

In LightBurn, the kerf offset setting is in the cut settings for each layer:

1. Select your cut layer in the Cuts/Layers panel.
2. Click the layer to open its settings.
3. Find "Kerf offset" and enter half your measured kerf (e.g., 0.1mm for a 0.2mm kerf).
4. Set the direction: outward makes the cut piece larger, inward makes it smaller.

When to use inward vs outward offset:

Actually, let's think about this more carefully. The laser removes material along the cut line. Without compensation:

• The piece that falls out is smaller than designed (laser ate material from each side)
• The hole left behind is larger than designed

So to get a snug fit:

• Offset the piece cut path outward by half the kerf (makes piece bigger)
• Offset the hole cut path inward by half the kerf (makes hole smaller)

Or use LightBurn's kerf offset and it handles the direction automatically based on whether the path is an inner or outer contour.

Kerf Values by Material

These are typical kerf widths for common laser setups. Your actual values will vary.

CO2 lasers generally produce narrower kerf than diode lasers because the beam is more tightly focused. Thicker materials tend to produce wider kerf because the beam diverges slightly as it passes through the material.

Design Rules for Laser Cutting

Before you export anything, your design needs to follow some physical constraints. Lasers are precise, but materials have limits.

Minimum Line Spacing

Your laser beam has a physical width (the kerf we just discussed). If two cut lines are too close together, they merge into one wider cut, or the thin strip between them is too fragile and breaks.

Rule of thumb: Keep at least 1mm between parallel cut lines for wood and acrylic. For thin or brittle materials, increase to 2mm. For robust materials like 3mm+ plywood, you can push down to 0.5mm, but test first.

This also applies to engraving near cut lines. If you engrave right up to the edge of a cut, the heat from cutting can scorch or distort the engraving. Leave at least 0.5mm between engraved areas and cut lines.

Minimum Feature Size

Very small features (thin tabs, tiny holes, delicate text) are limited by your laser's kerf and the material's structural properties.

Text: Always Convert to Outlines

This is non-negotiable. If your design has text, convert it to outlines (also called "converting to paths" or "expanding text") in your design software before exporting.

Why? Because text in a vector file is stored as font references. The letter "A" in Helvetica isn't a shape in your file. It's an instruction that says "render the letter A using the Helvetica font." If your laser software doesn't have Helvetica installed, it substitutes a default font. Your carefully chosen typography turns into Times New Roman or, worse, a missing glyph box.

Converting to outlines turns each letter into a fixed geometric shape. The font is baked into the geometry. It looks the same regardless of what fonts are installed on the receiving machine.

In Inkscape: Select your text, then Path > Object to Path.

In Illustrator: Select your text, then Type > Create Outlines.

In Affinity Designer: Select your text, then Layer > Convert to Curves.

Bridge Tabs for Parts That Fall Through

When you cut a piece completely free from the surrounding sheet, it drops through your honeycomb bed (or onto the slats, or into the void below). For small or delicate pieces, this can cause problems. The piece might land at an angle and catch the laser head. Or it might fall into an area where air assist blows it around.

Bridge tabs are small uncut sections that keep the piece attached to the surrounding material. After the job finishes, you snap or cut the tabs with a craft knife and sand the nubs.

To add bridge tabs in your design:

1. Find the cut path for your piece.
2. Remove small segments of the path (about 1-2mm wide) at 2-3 locations.
3. These gaps become the tabs that hold the piece in place.

Not all pieces need tabs. Large, heavy pieces usually stay put. Small, light pieces (under 20mm) almost always need them.

Overlapping and Duplicate Paths

This is the silent killer of laser files. Two paths stacked on top of each other look like one path on screen. But your laser runs both of them, burning the same line twice. On thin material, this can cut all the way through when you only wanted a score. On any material, it wastes time and increases charring.

Common causes of duplicate paths:

• Copy/pasting a shape and forgetting about the original underneath
• Boolean operations that leave remnant paths
• Importing the same file twice
• SVGs with both a stroke and a fill that get converted to two separate paths

How to check in Inkscape: Select everything (Ctrl+A) and look at the status bar for the object count. If you have more objects than expected, start selecting individual items to find the duplicates. Also try Edit > Find/Replace to search for identical paths.

How to check in LightBurn: Turn on "Show Traversal Moves" in the preview (Alt+P). If you see the laser returning to the same area twice, you have duplicate paths. Also check the "Optimization Settings" window and enable "Remove Overlapping Lines."

Common Software Workflows

Inkscape (Free, Cross-Platform)

Inkscape is the most popular free vector editor for makers. It's not the prettiest tool, but it handles SVG natively and does everything you need for laser file prep.

Laser prep workflow in Inkscape:

1. Set your document size to match your material or cutting bed. File > Document Properties > set width, height, and units (millimeters recommended).

2. Organize by color. Use different stroke colors for different operations. Red for cuts, black for engraves, blue for scores. No fill on cut and score paths (fill causes raster operations in some laser software).

3. Convert text to paths. Select all text, Path > Object to Path.

4. Convert objects to paths. Rectangles, circles, and other shapes should be converted to paths for reliable import. Select all, Path > Object to Path.

5. Check for overlapping paths. Extensions > Generate from Path > Check for Intersections. Or just visually inspect by dragging objects to see if there are hidden duplicates.

6. Set stroke widths. For cut lines, set stroke width to the minimum your software recognizes (0.001mm or "hairline"). Some laser software interprets thick strokes as engrave areas rather than cut lines.

7. Export as Plain SVG. File > Save As > Plain SVG (not Inkscape SVG). The Inkscape format includes extra metadata that can confuse some laser software.

Adobe Illustrator

If you're already paying for Illustrator, it's an excellent tool for laser file prep. The path handling is more robust than Inkscape, and the interface is more intuitive for complex designs.

Laser prep workflow in Illustrator:

1. Set your artboard to match your material size. Use millimeters.

2. Use separate layers or colors for each operation. The Layers panel keeps things organized, but what actually matters for LightBurn import is the stroke color.

3. Set all strokes to 0.001pt or "hairline." Illustrator's default stroke width is 1pt, which some laser software interprets as a thick line to be engraved rather than a cut path.

4. Create outlines on all text. Type > Create Outlines.

5. Expand all objects. Object > Expand. This converts strokes, effects, and other Illustrator features into simple paths.

6. Remove fills on cut paths. Cut lines should have a stroke color and no fill. Filled shapes get interpreted as raster engrave areas.

7. Save as SVG. File > Save As > SVG. Use SVG 1.1 profile, set images to Embed (if you have any), and set CSS Properties to "Presentation Attributes" for best compatibility with laser software.

LightBurn

LightBurn isn't just laser control software. It's also a capable design tool. For simple modifications and layout, you may not need a separate design program at all.

Useful LightBurn design features:

• Boolean operations. Select two shapes and use the toolbar to union, subtract, intersect, or XOR them. Great for creating cutouts and combined shapes.
• Text tool. Add and format text directly in LightBurn. It renders text to paths automatically, so font compatibility isn't an issue.
• Array/grid. Duplicate your design in a grid pattern to fill a sheet. Edit > Select All > Tools > Array.
• Offset tool. Create inset or outset paths at a specified distance. Useful for creating borders or adding kerf compensation manually.
• Node editing. Double-click a shape to edit individual nodes and curves. Fix problem areas without going back to your design software.

Import tips:

• If your imported SVG has color layers, they appear automatically in the Cuts/Layers panel. If everything imports as a single color, your SVG probably doesn't have color information.
• After import, use Edit > Select All, then right-click > Check for Duplicates. LightBurn will find and remove overlapping paths.
• Use the Preview window (Alt+P) before every job. It shows exactly what the laser will do, including travel moves, operation order, and estimated time.

LaserGRBL (Free, Windows Only)

LaserGRBL is a free alternative for GRBL-based diode lasers. It's simpler than LightBurn but gets the job done, especially for engraving.

File prep for LaserGRBL:

LaserGRBL is primarily an image-to-G-code tool. It excels at raster engraving (photos, filled graphics) but has limited vector support. For cutting, you'll typically use SVG files converted to G-code.

1. For raster engraving: Import your PNG or JPG directly. LaserGRBL handles the dithering and line-by-line conversion internally. Adjust brightness, contrast, and the dithering algorithm in the import dialog.

2. For vector cutting: Import your SVG. LaserGRBL converts the paths to G-code. Set your speed and power in the import settings. Note that LaserGRBL doesn't support multi-color layer mapping like LightBurn, so you may need to run separate files for cut vs engrave.

3. For mixed jobs: Split your design into separate files (engrave elements and cut elements) and run them sequentially with the same origin point.

If you find LaserGRBL's vector capabilities limiting, LightBurn's one-time $60 license is a worthwhile investment. The time savings from multi-layer processing and proper preview alone pay for it quickly.

Preparing Photos for Laser Engraving

Raster engraving (photos, filled graphics, logos) is a different workflow from vector cutting. Instead of path geometry, you're working with pixel data that gets converted to a dot pattern.

For a deep dive into photo-to-laser workflows, our photo engraving guide covers the entire process. Here's the file preparation summary.

Image Resolution

Your source image needs to be high enough resolution for the DPI you plan to engrave at. The math is simple:

Required pixels = physical size (inches) x DPI

So if you're engraving a 4" x 6" photo at 300 DPI, you need at least a 1200 x 1800 pixel image. Starting with a smaller image means the software has to upscale it, which adds blur.

Image Processing

Raw photos rarely engrave well. The continuous tones and gradients that look great on screen don't translate to laser burns on wood. You have two options:

Dithered engraving: Your laser software converts the grayscale photo into a pattern of dots. Multiple dithering algorithms exist (Floyd-Steinberg, Jarvis, Stucki, ordered), and each produces a different look. This works but requires careful tuning of contrast, brightness, and dithering settings for each material.

Line art conversion: Convert the photo to clean black-and-white line art before importing. The result looks like a pen-and-ink drawing and engraves cleanly on almost any material. Photo Converter does this with AI, producing results that look like hand-drawn illustrations. It costs one credit per conversion.

File Format for Raster Engraving

Use PNG for raster engrave files. PNG is lossless, so there are no compression artifacts in your image data. JPG introduces compression noise that can show up as random dots in your engraving, especially in light areas.

If your source file is a JPG (most photos are), that's fine as a starting point. But after you've processed it (adjusted contrast, converted to grayscale, applied dithering), save the final version as PNG before importing into your laser software.

Grayscale Conversion

Color images need to be converted to grayscale before engraving. Your laser software will do this automatically, but doing it yourself gives you more control.

In any image editor (Photoshop, GIMP, even Preview on Mac), convert your image to grayscale. Then adjust the levels or curves to boost contrast. Laser engraving tends to compress the tonal range (darks get very dark, lights get washed out), so starting with a higher-contrast image produces better results.

Converting Files Between Formats

Sometimes the file you have isn't the file you need. Maybe you designed in Illustrator but your machine wants DXF. Maybe someone sent you a PNG logo and you need to cut it. Maybe you downloaded a design as a PDF and need to extract the vectors.

Raster to Vector (PNG/JPG to SVG)

If you have a raster image (PNG, JPG) and need vector cut paths, you need to vectorize it. MonoTrace handles this for free. Upload your image, adjust the threshold and detail level, and download a clean SVG with proper vector paths.

MonoTrace works best with high-contrast images: logos, text, line art, silhouettes, and simple graphics. It's not designed for photographs (those should be engraved as raster images, not vectorized). For a detailed walkthrough, see our PNG to SVG conversion guide.

SVG to DXF

When your laser software or controller requires DXF format, File Converter handles the conversion for free. Upload your SVG, select DXF as the output, and download the converted file. It preserves geometry and handles bezier-to-spline conversion properly (no jagged curves).

Our SVG to DXF guide covers the common issues with this conversion, including unit mismatches, double-cut paths, and DXF version compatibility.

Other Useful Conversions

The Pre-Cut Checklist

Before you send any job to your laser, run through this checklist. Tape it to the wall next to your machine if you need to. Every experienced laser user has a mental version of this list. New users need to do it explicitly until it becomes habit.

File Integrity

• All text converted to outlines/paths
• No hidden or locked layers containing objects
• No objects outside the artboard/canvas
• File saved in correct format (SVG or DXF)
• Units match your laser software's workspace (mm recommended)

Path Quality

• No duplicate/overlapping paths (check in LightBurn preview)
• No open paths on shapes that should be closed (joins/boxes)
• All strokes set to hairline width for cut/score lines
• No fills on cut/score paths (fills trigger raster operations)
• Shapes converted from objects to paths (not rectangles, ellipses, etc.)

Layer Setup

• Each operation (cut, engrave, score) uses a different color
• Layers configured with correct operation type (Line vs Fill)
• Power and speed set appropriately for each layer and material
• Layer order: engrave first, score second, cut last
• Kerf offset applied to cut layers (for joints and press-fit parts)

Layout

• Design fits within the cutting bed
• Adequate margins from material edges (at least 5mm)
• Minimum line spacing between parallel cuts respected (1mm+)
• Bridge tabs added for small parts that might fall through
• Parts oriented for efficient material use (nesting)

Material and Machine

• Correct material loaded and secured
• Focus set for material thickness
• Air assist enabled (especially for cutting)
• Exhaust running
• Honeycomb bed clean (debris causes reflection and uneven focus)
• Fire extinguisher accessible

Final Verification

• Run LightBurn preview (Alt+P) and verify all operations
• Check estimated time (sanity check on settings)
• No unexpected travel moves or extra passes visible
• Origin/start position set correctly

Common Mistakes and How to Fix Them

"My cut pieces don't fit together"

Cause: No kerf compensation. Your tabs are slightly too small and your slots are slightly too large because the laser removed material on both sides of every cut line.

Fix: Measure your kerf (see the kerf section above) and apply kerf offset in LightBurn. For quick fixes, add 0.1mm to tab widths in your design and subtract 0.1mm from slot widths.

"The laser cuts the same line twice"

Cause: Duplicate paths stacked on top of each other. Looks like one line but your file contains two.

Fix: In LightBurn, select all objects and use Edit > Delete Duplicates. In your design software, check for hidden copies and remove them. In Inkscape, try selecting an object and pressing Tab to cycle through overlapping objects at the same position.

"My text looks different than the design"

Cause: Text wasn't converted to outlines. The laser software substituted a different font.

Fix: Go back to your design software, select all text, and convert to outlines/paths. Re-export and re-import.

"Everything imported as one big engrave instead of separate cuts"

Cause: Your design doesn't have color differentiation, or your shapes have fills instead of (or in addition to) strokes.

Fix: In your design software, set cut paths to have a colored stroke and no fill. Each distinct operation should use a different color. For SVGs, make sure you're using "stroke" attributes, not "fill."

"The cut didn't go all the way through"

Cause: Insufficient power, too fast, material thicker than expected, or focus is off.

Fix: This is a settings issue, not a file issue, but check that your file only has one path on the cut line (not a duplicate that you might think is the full cut). Verify material thickness with calipers. Refocus. Try another pass at the same settings before increasing power.

"Fine details broke or burned away"

Cause: Features too small for the material and kerf. Thin tabs, tiny text, or delicate details that can't survive the laser's heat.

Fix: Increase feature sizes to meet the minimums in the Design Rules section. Use a sans-serif font for small text. Remove overly delicate elements or simplify them.

"My design is the wrong size"

Cause: Unit mismatch between your design software and your laser software. Common when importing SVGs where the document was set to pixels instead of millimeters.

Fix: In your design software, set the document units to millimeters and verify the physical dimensions of your design. In Inkscape, use Document Properties to check. In LightBurn, verify the imported size and scale if needed.

"Engravings are blurry or have lines through them"

Cause for blurry: Source image resolution too low for the engraving DPI. If you're engraving at 300 DPI but your source image is 72 DPI, it's being upscaled 4x and losing detail.

Cause for lines: Mechanical issue (loose belt, dirty guide rails) or bidirectional scanning offset is miscalibrated. The latter shows up as a consistent horizontal shift on alternating scan lines.

Fix for blurry: Use a higher resolution source image. For raster engraving, source resolution should match or exceed your DPI setting.

Fix for lines: In LightBurn, adjust the scanning offset calibration. Run the built-in scanning offset test pattern at your engraving speed.

"Parts moved during the job and engraving is misaligned"

Cause: Cut operation ran before engrave operation. Cut pieces shifted on the bed before the engraving pass.

Fix: Reorder your layers: engrave first, cut last. In LightBurn, drag the engrave layers above the cut layers in the Cuts/Layers panel.

"The file imports but nothing shows up on the canvas"

Cause: Objects are placed far from the origin (0,0), or they're on a hidden layer, or the import scaled them down to near-invisible size.

Fix: After import, press Ctrl+Shift+A (or Edit > Select All) in LightBurn, then use Arrange > Move to Center or press Ctrl+Shift+C. If nothing selects, the objects might be on a hidden layer. Check the Cuts/Layers panel and make sure all layers are visible (eye icon).

Putting It All Together: A Complete Workflow Example

Let's walk through a real example. You're making a wooden coaster with an engraved design and a cut outline.

Step 1: Design. In Inkscape, create your coaster. Draw a 90mm circle in red (stroke only, no fill) for the cut line. Place your design inside the circle in black (fill for engraved areas, stroke for vector engrave lines).

Step 2: Text. Any text in the design gets converted to paths. Select text, Path > Object to Path.

Step 3: Check paths. Select all (Ctrl+A). Check the status bar for object count. Look for duplicate paths by dragging objects and checking for hidden copies underneath.

Step 4: Verify units. Document Properties > units set to mm. Circle diameter reads 90mm, not 90px.

Step 5: Export. File > Save As > Plain SVG.

Step 6: Import into LightBurn. File > Import. Your red circle appears on layer C01 (red), and your black design appears on layer C00 (black).

Step 7: Configure layers. Set the black layer to "Fill" (raster engrave) with appropriate power/speed for your material. Set the red layer to "Line" (cut) with cut settings. Drag the black layer above the red layer so engraving happens first.

Step 8: Kerf compensation. Your cut circle is the outline, so if you want the coaster to be exactly 90mm, apply outward kerf offset of half your measured kerf (e.g., 0.1mm for a 0.2mm kerf).

Step 9: Preview. Alt+P. The preview should show the raster engrave operation first (sweeping back and forth filling the black areas), followed by the cut circle. No duplicate paths, no unexpected operations.

Step 10: Position and cut. Set your origin, focus on the material, turn on air assist and exhaust, and run the job.

That's the whole process. Design, prepare, verify, cut. Once you've done it a few times, it becomes automatic. The checklist gets shorter because you stop making the mistakes it catches.

Material-Specific File Tips

Different materials have different tolerances and behaviors. Here are file preparation notes for the most common laser materials.

Wood

Wood is the most forgiving material for laser work. For detailed wood species recommendations, see our best wood for laser engraving guide.

• Kerf is moderate (0.15-0.25mm for diode, 0.1-0.2mm for CO2)
• Grain direction affects engraving appearance. Engravings across the grain look different than along the grain
• MDF is the most predictable because it has no grain variation
• Bridge tabs are essential for pieces under 15mm on honeycomb beds
• Leave extra margin for charring along cut edges (the heat-affected zone extends about 0.2-0.5mm beyond the kerf)

Acrylic

Acrylic cuts beautifully but has its quirks. Our acrylic cutting guide covers material selection and settings in depth.

• Kerf is narrower than wood (0.1-0.15mm on CO2 lasers)
• Leave protective film on during cutting (peel after). Set your file preparation accordingly since the film adds minimal thickness
• Acrylic is more prone to stress cracking near cut edges. Avoid placing cut lines too close together (minimum 2mm spacing for thin acrylic)
• For edge-lit designs, engrave and cut in the same job to maintain alignment

Leather

• Use lower kerf compensation (leather compresses slightly, offsetting the kerf)
• Test on scraps first. Different tannages and finishes respond very differently. For leather-specific guidance, see our leather engraving guide
• Avoid very fine details. Leather doesn't hold small features as well as wood or acrylic
• Synthetic leather containing PVC cannot be lasered safely

Paper and Cardstock

• Very narrow kerf (0.05-0.1mm). Kerf compensation is rarely needed
• Bridge tabs are essential since everything shifts immediately when cut free
• Minimum 0.5mm feature width. Paper is fragile
• Multiple passes at low power cut cleaner than single high-power passes
• Weight the material or use magnets. Air assist will blow loose pieces around

Metal (Marking Only)

Most hobby lasers can't cut metal, but CO2 and diode lasers can mark coated or treated metals. Fiber lasers cut and deeply engrave metal. For marking on metals, check our metal engraving guide.

• Design files for metal marking are typically raster (engraving only, no cutting)
• High contrast, simple designs work best
• Marking sprays (like CerMark or LaserBond) expand what diode and CO2 lasers can do on bare metal

Wrapping Up

File preparation isn't the exciting part of laser cutting. Nobody builds a laser to get really good at exporting SVGs. But it's the skill that separates people who get consistent, professional results from people who waste material and troubleshoot endlessly.

The core principles are simple. Use vector formats for cutting. Separate your operations by color. Convert text to outlines. Check for duplicate paths. Compensate for kerf on anything that fits together. Preview before you cut.

Once these habits are automatic, you spend your time on the creative work (designing, choosing materials, planning projects) instead of debugging files. And that's the whole point.

If you're just getting started with laser work, pair this guide with the laser engraving beginner's guide for machine setup and your first test engrave. If you're already comfortable with your machine and want to level up your material game, the wood settings cheat sheet and acrylic cutting guide have the specific numbers you need.

Happy cutting.