4 ms·

How to design parabolic, hyperbolic, elliptical reflectors for 3D printing

45 points by krisraghavan 10y ago

duke360 10y ago
ok for the 3d printing of the "structure" but then how to make it reflective? do you use regular allumination chamber or what technique ? which precision you can achieve to validate the prototype ?
- lutorm 10y ago
  Obviously it's for a metal 3d printer...
  - AlexTes 10y ago
    I don't think so. The cost would be extremely prohibitive. It would be far cheaper to print it in plastic and then add some reflectie coating.
  - sgnelson 10y ago
    Most metal 3d printers simply don't have the surface finish to make this feasible, never mind cost (it'd be ridiculous).
    - lutorm 10y ago
      I guess i should have added a ;-). Although the laser sintering printer downstairs produces quite nice surface finishes. Not good enough for an optical mirror, but definitely good enough for mm-wave antennas.
- noonespecial 10y ago
  I've had outstanding luck with this paint (1). Print your model in ABS. Smooth it by putting it in a paint can on a little stand with some acetone soaked rags below for about 1/2 hour. Paint with some of this paint. You will be amazed. (1) https://www.amazon.com/Krylon-1010A-Premium-Metalic-Original/dp/B000C027P4 https://www.amazon.com/Krylon-1010A-Premium-Metalic-Original...
chris_va 10y ago
If you had a specific design in mind, it might actually be more satisfying to generate the STL triangles directly. You can fit your parabola in 2D (by, say, computing reflection angle to a fixed focal point), then just rotate and dump out STL. The wiki has a nice intro to the subject: https://en.wikipedia.org/wiki/Parabolic_reflector https://en.wikipedia.org/wiki/Parabolic_reflector
pauw 10y ago
Alternatively, one could use the "define curve by equations" feature. Most CAD tools have it.
sgnelson 10y ago
This is a nice tutorial, but it seems a bit kludgey (and I'm guessing part of that is due to Fusion 360's "not quite a fully finished CAD system," though they are making pretty good progress with it, and I find it's a fairly nice program, especially for the price, (free to hobbyists) and it includes CAM abilities.) I would think OpenSCAD would be pretty decent at this, but honestly, I've never tried making parabola's or similar with it. A quick google found this openscad script for parabolas: http://www.thingiverse.com/thing:84564 http://www.thingiverse.com/thing:84564

45 points by krisraghavan 10y ago

ok for the 3d printing of the "structure" but then how to make it reflective? do you use regular allumination chamber or what technique ? which precision you can achieve to validate the prototype ?

lutorm 10y ago
Obviously it's for a metal 3d printer...
- AlexTes 10y ago
  I don't think so. The cost would be extremely prohibitive. It would be far cheaper to print it in plastic and then add some reflectie coating.
- sgnelson 10y ago
  Most metal 3d printers simply don't have the surface finish to make this feasible, never mind cost (it'd be ridiculous).
  - lutorm 10y ago
    I guess i should have added a ;-). Although the laser sintering printer downstairs produces quite nice surface finishes. Not good enough for an optical mirror, but definitely good enough for mm-wave antennas.
noonespecial 10y ago
I've had outstanding luck with this paint (1). Print your model in ABS. Smooth it by putting it in a paint can on a little stand with some acetone soaked rags below for about 1/2 hour. Paint with some of this paint. You will be amazed. (1) https://www.amazon.com/Krylon-1010A-Premium-Metalic-Original/dp/B000C027P4 https://www.amazon.com/Krylon-1010A-Premium-Metalic-Original...

chris_va 10y ago

If you had a specific design in mind, it might actually be more satisfying to generate the STL triangles directly. You can fit your parabola in 2D (by, say, computing reflection angle to a fixed focal point), then just rotate and dump out STL. The wiki has a nice intro to the subject: https://en.wikipedia.org/wiki/Parabolic_reflector https://en.wikipedia.org/wiki/Parabolic_reflector

pauw 10y ago

Alternatively, one could use the "define curve by equations" feature. Most CAD tools have it.

sgnelson 10y ago

This is a nice tutorial, but it seems a bit kludgey (and I'm guessing part of that is due to Fusion 360's "not quite a fully finished CAD system," though they are making pretty good progress with it, and I find it's a fairly nice program, especially for the price, (free to hobbyists) and it includes CAM abilities.) I would think OpenSCAD would be pretty decent at this, but honestly, I've never tried making parabola's or similar with it. A quick google found this openscad script for parabolas: http://www.thingiverse.com/thing:84564 http://www.thingiverse.com/thing:84564