Pick your fan size and get a printable guard that bolts to it — hole spacing from ARCTIC's drawings and NopSCADlib's measured fan table, a 2 mm standoff from the blades. The pattern copies the steel wire guard on purpose: in wind-tunnel tests wire guards cost almost no airflow, while a half-open honeycomb sheet cost about a fifth of it.
The real generator runs in your browser: set the parameters, then download STEP or STL. Nothing to install, no sign-up.
The first open downloads the CAD engine (about 20 MB).
Each parameter below rebuilds real geometry on every change — this is parametric CAD, not a scaled mesh.
| Parameter | Default | Range | What it does |
|---|---|---|---|
| Fan sizeFAN | 120 mm | 25 – 140 mm | Hole spacing from ARCTIC's drawings (40, 80, 92, 120, 140 mm) and NopSCADlib's measured fan table (25, 30, 50, 60, 70 mm). |
| Bar widthBAR | 1.2 mm | 0.8 – 3 | 1.2 mm or more prints cleanly from a 0.4 mm nozzle. |
| Max opening widthGAP | 4.8 mm | 2.5 – 12.7 | Rings are spread evenly so no gap is wider than this. 12.7 mm (½ in) is the OSHA limit for fan guards. |
| Grill thicknessGRILL_T | 1.6 mm | 0.8 – 4 | The ring layer, printed flat on the bed. |
| Standoff from fanSTANDOFF | 2 mm | 0 – 5 | Space between the rings and the blades; Noctua's steel guards stand 5 mm off. |
| Screw holeSCREW | auto | auto / fan screw / M4 / M3 | Auto: M2.5 under 30 mm, M3 for 30–40 mm, the 5 mm fan screw from 50 mm. |
Every parameter can go in the page's link, so one link opens exactly the part you want. Example (92 mm fan (82.5 mm hole spacing), M3 holes):https://www.forgent3d.com/en/generators/fan-grill-generator?FAN=92&SCREW=M3
STEP AP214 in millimetres, exact B-rep — it opens directly in SolidWorks, Fusion, FreeCAD, Onshape or Inventor, and goes straight into a CNC quote form. STL for the slicer is one click too.
| This generator | Typical online STL generator | Vendor CAD library | |
|---|---|---|---|
| Any size within the range | Yes | Yes | Catalog sizes only |
| STEP with exact surfaces | Yes | Usually an STL mesh only | Yes |
| Changes the sliders don't cover | “AI edit” on the page | No | No |
| Account needed to download | No | Usually no | Often |
Every parameter is a link parameter; the link below opens the example part. ChatGPT, Claude or any assistant can write one like it from the parameter list (names, units, ranges) at: parameter list (JSON)
Example: https://www.forgent3d.com/en/generators/fan-grill-generator?FAN=92&SCREW=M3
Press “AI edit” in the generator and say what to change — a keyway, holes, a different shape. The AI edits the part's model.py and it rebuilds in your browser, with undo. A few edits a day are free without signing in; to keep the result or go further, copy it into your models and continue with the AI agent.
Edit with AI →For bigger changes, several rounds, or a part you want to keep: copy it into your models (free account). The Forgent3D AI agent reads the model.py, edits it, rebuilds it and checks the result itself.
Copy and continue with the AI agent →Because it moves more air and makes less noise. hwcooling measured a wire guard costing 0–2 % of a 120 mm fan's airflow, while a hexagonal sheet half covered in metal cost about 20 % and added 3 dBA. Puget Systems' grill test ranked wire guards best too. Nobody has measured printed grills yet, so treat thinner bars and wider openings as the safer side.
From 50 mm up, the standard self-tapping fan screw goes through the grill into the fan; the holes are 5 mm, the size of ARCTIC's steel guard eyes. 40 mm and smaller fans use M3 (M2.5 for 25 mm). The grill adds its own thickness, so you need a screw that much longer than a bare fan takes.
Flat, ring side down, exactly as it is generated — nothing bridges, so no supports. Keep the bars at 1.2 mm or wider with a 0.4 mm nozzle. Use PETG if the grill sits near a heat source.
https://www.forgent3d.com/en/generators/fan-grill-generator?FAN=92&SCREW=M3 — the hole spacing (82.5 mm) comes with the fan size. Download STL; it prints flat with no supports.
Press “AI edit” in the generator and describe it; the AI edits the guard’s model.py on the page. Keep the openings large: the rings-and-spokes pattern is there because wire-style guards cost the least airflow.
Yes. Models you generate and the STL / STEP files you export are yours: print them, sell the prints, or use them in a product. No attribution to Forgent3D is required.
Already have your own .scad file? Convert OpenSCAD to STEP → · Preview it in the browser →
