A 3D printable parabolic dish antenna, written in OpenSCAD, with examples rendered for immediate print.
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| Included example render: 200mm tiles, 800x800mm dish size, focal distance 500mm |
FDMdish is a 3D printable, scalable parabolic reflector surface system suitable for use in a high gain radio antenna setup. The parametric model is generated in OpenSCAD, STLs can be rendered/exported and used to generate tiles that can be 3D printed. The accompanying Cura slicer settings have been optimised for high speed printing, using a low volume of material for high paraboloid surface accuracy up to ~10Ghz (maybe 20GHz, requires testing).
The tiles are mounted to a frame of 2020 aluminium extrusion. Use some currently unknown method to place the RF antenna feed at the focal point.
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| Rear view, showing supports | Tiles are labeled |
- Ideal 3D printer: Artillery Sidewinder X1, with a 0.8mm nozzle for 1mm line width and 0.5mm layer height. Or equivalent machine
- A few KG of PLA filament, the slicer will tell you how much you need, white is less likely to melt in the sun than black
- Lengths of 2020 vslot extrusion or square hollow section, other widths are possible if you modify the OpenSCAD script
- Brackets to hold the 2020 extrusion in a sturdy frame (see images for examples)
- M5 (ideal), M4 or M3 fasteners and slot nuts
- Beers and patience
- Conductive tape, or conductive nickel spray paint for the reflector surface
- Specific custom tiles can be generated by adjusting the parameters in the OpenSCAD script
- Whole dish assemblies can be batch rendered by modifying the parameters in the shell script, and running it (gen_dish.sh)
- The rendered STL files will be stored in the ./render folder
- Check the whole render job, but importing the STLs into a new FreeCAD project
- Load each of these files into your slicer of choice (an optimised profile for CURA and the Sidewinder X1 has been included for tips)
- The 3D printer and slicer should be set up for printing of dimensionally accurate functional components, otherwise there may be a few tight fits
- Print each tile out, trimming the brim
- Once printed, the tiles can be fastened to a grid of 2020 extrusion
- Get creative with ensuring the surface of the dish is electrically conductive, at least in the direction of polarisation, examples include:
- Copper tape, spaced less than 1/10 wavelength apart
- Conductive nickel spray paint
- AluminIum foil and adhesive
- Thin wire, taped down, ghetto pride
- A high speed, thick layer height print process is unlikely to be tolerant of anything more than a 45deg overhang
- So the on-axis diameter should be less than 4 times the focal length
- For a square dish at this critical limit, the corners are likely to exceed this requirement and may need to be discarded
- The SCAD model and slicer settings have been optimised for each other, the outcome may be less than ideal with a narrower nozzle
- The structural strength comes from the aluminium extrusion, these panels are designed to be rigid and low warp, but not load bearing
- 1 shell wall, fill of approximately 5-10% with a zigzag pattern seems to provide enough strength to prevent warping in the paraboloid as it cools
- Black gloss filament is good as a prototyping filament, because the quality of the surface can be quickly observed by looking for variations in the reflective sheen as the tile is rotated under a point source of illumination
- printing with a brim is essential (these components are large, with a low bed contact area, and are otherwise likely to lift off the bed)
- Approximate time per tile with the described setup: 2-3 hours