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To prepare a file for laser cutting, save your design as a DXF or DWG vector file with all paths closed, fonts converted to outlines, no duplicate or overlapping lines, and dimensions in millimetres. The file should contain only the cut geometry with no dimensions, annotations, or construction lines included. A clean, correctly set up file goes straight to the machine. A file with common errors gets sent back for correction, which delays the job.
This guide covers every step of the file preparation process, the most common mistakes that hold jobs up, and what to do if you don’t have a vector file ready.
The standard file formats for laser cutting are DXF and DWG. These are vector file formats that store geometry as mathematical paths rather than pixels, which is what a CNC laser cutting machine reads to follow the cut path accurately.
DXF (Drawing Exchange Format) is the most universally compatible format and the one we prefer at Big 5 Products. It can be exported from almost every CAD and design software package including AutoCAD, Fusion 360, SolidWorks, Rhino, FreeCAD, Adobe Illustrator, CorelDraw, and Inkscape.
DWG is AutoCAD’s native format and is equally acceptable. If you work in AutoCAD, saving in DWG is fine.
PDF, JPEG, PNG, and other raster or document formats are not directly usable for laser cutting. They contain no vector path data and must be manually redrawn or traced into a vector format before cutting can begin. We can do this for you but it adds a design fee and time to the job. If you have a choice between sending a PDF and a DXF, always send the DXF.
Set your drawing units to millimetres before you start and confirm they are still set to millimetres when you export. This sounds basic but it is one of the most common file errors we receive. A drawing exported in inches and interpreted as millimetres produces a part that is 25.4 times larger or smaller than intended. A drawing exported in metres interpreted as millimetres produces parts measured in kilometres.
Always confirm the unit setting in your software’s export dialog before saving the DXF. If you are not certain what units your file is in, state it explicitly when you send the file so we can confirm the scale matches your dimensions before cutting begins.
Every shape you want cut must be a closed vector path. A closed path is one where the start point and end point of the line connect exactly, forming a complete, unbroken outline of the shape. An open path has a gap between the start and end points, which means the laser cutting software cannot identify it as a complete shape to cut.
Open paths are one of the most common file problems in laser cutting submissions. They often come from:
Zooming out too far when drawing and missing that two endpoints are close but not touching. Importing or tracing geometry from other file types where small gaps are introduced at the import stage. Drawing arcs and lines separately and not joining them at the endpoints. Using trim and extend tools that leave small overhanging segments at corners.
Check for open paths before exporting by using your software’s path validation or gap detection tools. In AutoCAD, the AUDIT and OVERKILL commands help identify and fix these issues. In Illustrator, Object > Path > Join closes open endpoints. In Inkscape, Extensions > Generate from Path > Interpolate can identify gaps.
At Big 5 Products we review every file before cutting and flag open paths. We can often fix minor gaps quickly, but a file with many open paths adds time and may incur a file correction fee.
If your design includes any text or lettering, convert it to outlines or curves before exporting. Fonts are stored as font data that references the font file installed on the originating computer. When the file is opened on a different computer or in different software for cutting, the font may not be installed, causing the text to substitute with a different font or display incorrectly.
Converting text to outlines converts the letter shapes into vector paths that are embedded in the file and display correctly regardless of what fonts are installed on the receiving computer or machine.
In AutoCAD, use EXPLODE on text to convert to polylines. In Illustrator, select all text and go to Type > Create Outlines. In CorelDraw, select text and use Text > Convert to Curves. In Inkscape, select text and use Path > Object to Path.
After converting, verify the letter shapes look correct and that the outlines are closed paths. Fonts with thin serifs or fine detail may require a minimum thickness check — letters that are too thin for the material thickness and laser kerf may not cut cleanly.
Duplicate lines are two or more identical lines sitting exactly on top of each other in the same position. They are invisible when looking at the drawing but cause the laser to cut the same path twice, which wastes time, increases heat input on the material, and can cause distortion or burning on thin material.
Overlapping lines occur when two paths cross each other and one extends beyond the intersection point. The laser cuts both paths in full, meaning it cuts into areas that should be left intact.
In AutoCAD, the OVERKILL command removes duplicate entities and merges overlapping segments. In Illustrator, use Pathfinder > Divide and then delete unwanted segments. In most software, a visual check at high zoom level catches the most obvious overlaps.
Your DXF file should contain only the geometry you want cut. Dimensions, annotations, text labels, construction lines, centre lines, and title blocks must all be removed or placed on a separate layer that is excluded from the export.
Dimension lines and annotation text that are not converted to outlines will either be ignored by the cutting software or, worse, interpreted as cut paths. A dimension line across the middle of your part will result in an unwanted cut line through the finished piece.
The cleanest approach is to draw your cut geometry on a dedicated layer, turn off all other layers, and export only the visible geometry. This eliminates any risk of non-cut content appearing in the cutting file.
Laser cutting has physical limits on the minimum feature size it can produce cleanly. These limits depend on the material, the thickness, and the laser kerf width — the width of material removed by the laser beam as it cuts.
As a general guide for most standard laser cutting jobs:
The minimum hole diameter should be at least equal to the material thickness. A 2mm hole in 3mm material is at the limit of what produces a clean result. A 1mm hole in 3mm material will not cut cleanly.
The minimum bridge width between cut-out areas should be at least equal to the material thickness to avoid the remaining material being too thin and fragile.
Very fine detail, hairlines, and features smaller than 0.5mm in most materials will not reproduce accurately and may cause the laser to skip or produce a rough cut at that feature.
If your design has features close to these limits, flag them when you send the file. We review every file before cutting and will advise if any features are likely to cause problems before the job starts.
Before exporting, zoom out and check that the overall dimensions of your drawing match the intended part dimensions. It is easy to introduce a scale error when copying geometry between documents, importing reference material, or working with multiple scale drawings on the same layout.
A quick sanity check: measure one known dimension in your drawing software before exporting and confirm it matches the real-world dimension you intend. If you are drawing a 500mm by 300mm panel, confirm the drawn geometry measures 500mm by 300mm in your software before saving the file.
If you are not certain the scale is correct, include a note with the file stating the intended overall dimensions of the part. We will check the file against those dimensions before cutting begins.
Once you have completed the above steps, export the file as DXF. Open the exported file in a viewer before sending it to confirm the geometry looks correct, is the right scale, and contains no unexpected elements. Free DXF viewers including DraftSight, eDrawings, and online tools like ShaprViewer allow you to open and check DXF files without a full CAD licence.
A DXF that opens correctly in a viewer and shows the geometry at the right scale is ready to send.
If you only have a JPEG, PNG, or PDF of your design and no vector file, you have three options:
Redraw it in CAD. The most accurate approach for precise parts. Draw the geometry from scratch in AutoCAD, Fusion 360, or FreeCAD using the image as a reference. This takes time but produces a clean, accurate file.
Trace it in vector software. Use Illustrator or Inkscape to manually trace the outline of the image into vector paths, then export as DXF. Auto-trace tools exist in both programs but they rarely produce clean, accurate results for precision parts — manual tracing is usually more reliable.
Send it to us. We can convert simple designs from PDF or image to a production-ready DXF, but this adds a design fee to the job and time before cutting can begin. For simple shapes this is quick. For complex designs with fine detail it takes longer. Always better to send a vector file if you have one.
Before sending your file, confirm each of the following:
File format is DXF or DWG. Units are set to millimetres. All paths are closed. All fonts and text are converted to outlines. No duplicate or overlapping lines. No dimensions, annotations, or construction lines in the cut layer. Minimum feature sizes are above the material thickness. Overall dimensions have been verified against intended part size. File opens correctly in a DXF viewer.
DXF and DWG are the standard file formats for laser cutting. Both are vector formats that store geometry as mathematical paths, which is what CNC laser cutting software reads. PDF, JPEG, and PNG are not directly usable — they must be converted to vector format before cutting can begin.
A closed path is a vector line where the start point and end point connect exactly, forming a complete, unbroken outline. The laser cutting software uses closed paths to identify shapes to cut. Open paths, where the start and end points don’t connect, cannot be interpreted as complete shapes and cause errors in the cutting file. Check for open paths before exporting using your software’s path validation tools.
Millimetres. Always confirm your drawing units are set to millimetres before exporting. A file in inches or metres interpreted as millimetres produces a part at the wrong scale. If you are unsure, state the intended overall dimensions of the part when you send the file so the scale can be confirmed before cutting.
As a general guide, the minimum hole diameter should be at least equal to the material thickness. A 2mm hole in 2mm material is at the practical limit. Smaller holes relative to material thickness may not cut cleanly or may produce an inaccurate result. Flag any very small holes when you enquire and we will advise before cutting begins.
For most standard fabrication jobs, no. The laser cutting machine operator sets up the kerf offset in the cutting software based on the material and laser parameters. For very tight tolerance parts where kerf width materially affects the fit of assembled components, it is worth discussing kerf compensation before the job starts.
A PDF is not directly usable as a laser cutting file. It needs to be converted to a DXF vector file before cutting can begin. We can convert simple designs from PDF for a design fee, but a DXF file produced in your CAD or design software is always faster and more accurate. If your design software can export DXF, always use that rather than PDF.
We review every file before cutting and flag any problems — open paths, duplicate lines, scale errors, or features below minimum size — before the job starts. Minor issues we can often fix quickly. Files with significant errors may incur a file correction fee or be returned for revision before cutting begins. The checklist in this guide covers the most common issues and following it means most files arrive ready to cut without correction.
A hand-drawn sketch with clear dimensions is a workable starting point for simple shapes. We can draw up the cutting file from a sketch and dimensions, but this adds a design fee and time before cutting begins. For anything with curves, precise radii, or complex geometry, a CAD file is significantly more accurate than working from a sketch.
Once your file is ready, send it to us with your material specification, material thickness, quantity, and any finish or tolerance requirements. We review the file, confirm it is production-ready, and come back with a price and lead time in one conversation.
Call us on 072 506 6551 or 082 900 0566, or [contact us through the website]. We are at 20 Ring Street, George Industria, George, Western Cape.
For more on our laser cutting capability see [fibre laser cutting South Africa] and for local service detail see [laser cutting George].