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48108Re: [SeattleRobotics] Planning laser cut project

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  • James Hughes
    Nov 3, 2013
      Here's a few things:
      •  3dtin.com
      • Tinkercad.com
      • Sketchup
      • OpenSCAD
      • Wings3D
      • Scupltris
      • Autodesk 123D
      • Blender
      • POV-ray
      • FreeCAD
      • HeeksCAD
      • Art of Illusion

      The inkscape recommendation is a good one, but one caveat about non-CAD drawing tools (inkscape, illustrator, etc) is that they typically don't handle units correctly. They use floating point values, which have approximation errors. It's really only a problem if you need parts to fit tightly together. If you can live with a little slop, then it's not a big deal. You can always do a little sanding if the parts don't fit together, but if your shapes are extremely complex this will quickly become tedious. For bolt holes, just size them for a "free" fit so things can wiggle around a bit before you tighten the bolts. I've made plenty of parts for laser cutters and even CNC machines using illustrator and inkscape, so it works. It just depends on your application and your tolerance requirements.

      FYI, if you're on a Mac, you can download and use Rhino for free. It's pretty easy to use and has a wealth of features. The Mac version is a work in process so has a lot of unimplemented features and one of the big black holes is file import/export. So check and see if Pololu supports something the Mac version can write.


      On Sat, Nov 2, 2013 at 3:19 PM, Wim Lewis <wiml@...> wrote:
       

      On 11/2/13 11:57 AM, Randy Carter wrote:
      > I'm planning a project made of ABS plastic. I was thinking of using Pololu's laser cutting service to make the parts. What kind of CAD program is good to use, preferably cheap (aka free)? Are there any pitfalls I should try to avoid? Can parts be nested so that waste cut out of part A can be used to make parts C and D? Do they charge extra for using 2 or more thicknesses of material?

      I haven't used Pololu's, but I've used Metrix's laser cutter for a few
      things.

      The things I've done haven't required sophisticated CAD functionality,
      so I've just used Inkscape. I usually only need to position some holes
      and edges precisely and can basically freehand the rest. Once you
      familiarize yourself with the program it can be pretty effective for
      pseudo-CAD use (the various "snap-to-X" settings and boolean-path-ops
      are very handy).

      Pololu's Q&A says you can nest parts but you might need to tell them
      that explicitly: <http://www.pololu.com/product/749/faqs> Metrix often
      gives me the various cutout bits from my job just by default.

      I'm guessing they'll charge you more for using multiple thicknesses
      because they'll need to use multiple sheets of material, so you'll get
      their $25 per-panel charge for each distinct thickness. Just from a
      glance at their website, it doesn't look like they combine multiple
      customers' jobs onto one panel. Metrix is sometimes willing to cut a
      small job from a scrap piece hey have in their bin and not charge you
      for the material, but it's luck of the draw.


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