Preparing a DXF for laser cutting

Why the file matters

A fiber laser follows the lines in a DXF exactly. It cannot tell a cut line from a dimension, a centre line or a stray construction line. Every extra line is either cut, which ruins the part, or cleaned up by hand before cutting, which costs time. A clean file is priced faster, nested more efficiently and cut right the first time.

The DXF checklist

1. Draw at full size, in millimetres

Draw at 1:1 scale with millimetres as the unit. A file drawn in inches, or scaled for printing, produces parts at the wrong size. If unsure, add one known dimension in the covering message, such as "overall width 450 mm".

2. Use closed contours only

Every outline and hole must be a closed shape. Small gaps where two lines nearly meet stop the cutting software recognising the contour. Joining lines into closed polylines fixes this.

3. Remove duplicate and overlapping lines

Lines drawn twice on top of each other are invisible on screen but get cut twice, which burns the edge and wastes time. Use the CAD program's overkill or delete-duplicates command before exporting.

4. Keep only cut geometry on the cutting layer

Remove dimensions, title blocks, borders, notes and centre lines, or move them to a separate layer clearly named as reference.

5. Convert splines and text to simple geometry

Splines and live text can export unpredictably. Convert splines to polylines or arcs, and explode text into outlines if it is to be cut.

6. Draw to finished size

Draw the part at its finished dimensions. The beam removes a thin strip of material, called the kerf, and this is compensated in programming. There is no need to offset lines.

7. One part per file, or clearly separated

Send one part per DXF, or keep parts well apart in one file with a label for each. File names that say what they are help, for example bracket-A_MS_3mm_qty40.dxf.

Holes, slots and text

• Hole size: keep hole diameters at least equal to the material thickness. In thick plate, very small holes are better drilled after cutting.
• Web width: leave at least one material thickness of solid metal between holes, slots and the edge.
• Text and logos: letters with enclosed areas, like A, O and R, need small bridges or the centre falls out. A stencil font works well, as on the AVIOR AQUA lettering in the projects.
• Internal corners: a tiny radius in internal corners reduces stress, which matters on parts that will be bent or loaded.

Parts that will be bent

If the part goes on the press brake after cutting, the flat pattern has to allow for the material that stretches in each bend. Two good options:

• Send a 3D STEP model of the finished part, so the flat pattern is developed for the tooling.
• Send the flat pattern with bend lines on a separate, named layer, plus a drawing showing bend directions, angles and inside radius.

Whether a part can be bent depends on its thickness, bend length and flange sizes. The guide to bend radius and flange length covers the design rules.

What to send with the file

No DXF yet? A PDF drawing, a dimensioned sketch or a clear photo is enough to start, and a paid drawing-preparation service can produce the file. Files can be sent on WhatsApp or by email from the contact page.