From Vector to Laser: Preparing SVG Artwork for CNC and Laser Cutters

A lot of maker projects start with an SVG: an enclosure panel for a microcontroller board, a sensor bracket, a robot chassis plate, a nameplate for a workshop. SVG is easy to draw and easy to share, but CNC routers and laser cutters are happiest with DXF and a design that respects how the machine actually removes material. This post walks through the decisions that turn a nice-looking vector into a part that fits on the first try.

Design for the tool, not the screen

On screen, a line has no thickness and a corner can be perfectly sharp. In the workshop neither is true.

Lasers have kerf. The beam vaporises a thin strip of material — commonly a tenth of a millimetre or two, depending on the machine, lens and material. A slot drawn at exactly 3.0 mm for a 3.0 mm panel will come out loose. Cut a test comb of slots at 2.8, 2.9 and 3.0 mm on your material and use the one that gives the press fit you want.

Router bits are round. A CNC router with a 3 mm end mill cannot make a sharp internal corner; it leaves a 1.5 mm radius. If a square part has to sit in a square pocket, add "dog-bone" or "T-bone" relief cuts at the inside corners. That is a design change in your SVG, not something the converter can fix later.

Minimum feature size is real. Thin bridges between cut-outs warp or burn on a laser and snap on a router. As a rough starting point, keep webs at least as wide as the material is thick, then adjust from experience.

Build the SVG so it converts cleanly

Machines read geometry, so the cleaner the geometry, the fewer surprises.

1. Work in real units. Set the document to millimetres and give the
2. Use closed paths for anything that should drop out. Mounting holes, cable openings and the outer profile should all end with a close command.
3. Outline your text. Engraved labels such as "USB", "5V" or "GND" must be converted to paths. Fonts don't travel inside a DXF.
4. Colour-code operations. A common convention: red for through-cuts, blue for scoring, black for raster engraving. Your laser or CAM software can map colours to power and speed settings.
5. Remove decoration. Drop shadows, gradients and embedded photos have no meaning to a cutter.

A worked example: a sensor mounting plate

Say you are making a 60 × 40 mm acrylic plate to hold a small sensor board with four M3 mounting holes.

• Outer profile: a rounded rectangle, 60 × 40 mm, 3 mm corner radius, red.
• Mounting holes: four circles at 3.2 mm diameter (a little clearance over M3), red.
• Cable slot: a 10 × 4 mm rounded slot, red.
• Label: the board name in outlined text, black, for engraving.
• Reference: a 10 mm square in a separate layer you will hide after checking scale.

Inner features — holes and slot — should be cut before the outer profile so the plate does not shift once it is free.

Converting SVG to DXF

You have several options:

• Desktop CAD or vector software. Inkscape and most CAD packages can save DXF directly. Check which DXF version your machine software expects; older R12/R14 files are the most widely compatible.
• CAM software import. Some laser and router programs import SVG directly, which can skip the step entirely.
• Online converters. For quick jobs, a browser-based DXF export tool saves you installing anything, which is handy on a shared workshop PC.

Whatever you use, open the DXF before cutting and check three things: the reference square measures 10 mm, curves arrive as arcs or smooth splines rather than jagged segments, and every cut shape is still closed.

Before you press start

• Material is flat and secured; warped sheets defocus a laser and lift on a router.
• Air assist and extraction are on.
• Power and speed match the material — run a small test grid if you are unsure.
• You have done a dry run or a frame trace to confirm the job fits the sheet.
• Someone stays with the machine for the whole job.

Keep a parts library

Once a plate fits, save the SVG and the DXF together with notes on material, thickness, kerf and machine settings. The next enclosure starts from a proven file instead of a blank canvas, and the fit you achieved once becomes repeatable.

Good laser and CNC work is mostly preparation. Get the geometry, units and tolerances right in the SVG and the conversion becomes the easy part.