The three design rules behind 90% of rejected DXFs
Tiny holes, features hugging the edge, and "sharp" inner corners — why the physics says no, and the one-line fixes that keep your quote from bouncing back.
Why files bounce
Last month we quoted 412 DXF files. Thirty-eight went back to their owners with red markup before a single sheet moved — and nearly all of them broke one of the same three rules.
None of this is style. It comes down to what a 0.2 mm beam of light physically does to molten metal. Learn the three rules once and your files go straight from inbox to nesting — which is how a 24-hour quote actually happens in 24 hours.
Holes narrower than the sheet is thick
A laser doesn’t drill; it pierces, then orbits. For the melt to escape the kerf cleanly, the hole must be at least as wide as the material is thick. Below ⌀ 1 × t the beam re-melts its own edge on the way around — you get taper, dross on the underside, and a hole no bolt will thank you for.
| SHEET t | MIN ⌀ — STEEL · O₂ | MIN ⌀ — STAINLESS · N₂ |
|---|---|---|
| 1.5 mm | ⌀ 1.5 | ⌀ 1.8 |
| 3 mm | ⌀ 3.0 | ⌀ 3.6 |
| 6 mm | ⌀ 6.0 | ⌀ 7.2 |
| 10 mm | ⌀ 10.0 | — |
Over 8 mm stainless, talk to us first — gas choice depends on the edge you need.
Need smaller? Have us cut a centre mark and drill the hole in post — it’s nearly always cheaper than fighting the beam.
Features hugging the edge
Every cut dumps heat into the part. A hole that hugs the edge leaves a thin web of metal heated from both sides at once — it warps, discolours, or blows out entirely. The same goes for two features crowding each other.
If the geometry is non-negotiable — flanges, hinge knuckles — tell us. We can slow the feed and pulse the pierce, but that’s a decision for the quote, not a surprise for the machine.
The beam is a tool with a width. Design as if it exists, and it behaves as if it likes you.
Zero-radius inside corners
CAD will happily draw an infinitely sharp inner corner; a beam with a 0.2 mm kerf cannot cut one. Forced into it, the machine decelerates to a stop, dwells, and burns a notch exactly where your part concentrates stress.
Outside corners are free — the beam simply travels past them. It’s only the inside ones that ask it to turn on a point.
Before you export
Three rules for geometry; five habits for the file itself. This is the exact list taped above the nesting PC:
- 01 Scale 1:1, in millimetres If a 100 mm edge measures 3.937, it came from inches. We catch most — not all.
- 02 Explode text and dimensions to curves Fonts don’t travel. Anything still "live" gets skipped by the nest.
- 03 Purge duplicate and overlapping lines Stacked lines cut twice: double heat, burned edge.
- 04 Close every contour Gaps under 0.01 mm still break the toolpath.
- 05 Material and thickness in the filename bracket_SS304_2.0.dxf answers three emails before they’re sent.
Not sure your file passes?