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Planning Sketchup vs Other CADs for CNC machining

Discussion in 'Modding' started by BD Hopkins, 9 Jul 2014.

  1. BD Hopkins

    BD Hopkins What's a Dremel?

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    Hey all,

    First, I've been told that .dxf is the most common format accepted by CNC machinists, because it originated via AutoDesk, the CAD that has been around decades. Please confirm, if you would.

    Second, if true, do the latest versions of Sketchup Make or Sketchup Pro have any issues converting to .dxf format for submission to CNC machinists?

    I already know Sketchup, but I'm willing to learn AutoCAD or something else if it's necessary. Thanks.
     
    Last edited: 9 Jul 2014
  2. asura

    asura jack of all trades

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    If you've got SketchUp Pro, a DFX exporter plugin for the free version, or a SKP to DFX converter then you should be fine I guess. DFX's are by their nature simple creatures - AutoDesk do a free DFX/DWG viewer, which you can use to check for any export issues. I have no experience in getting stuff machined however.
     
  3. Flibblebot

    Flibblebot Smile with me

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    Just be careful that SketchUp doesn't produce proper circles, instead it produces a series of segmented lines. You can increase the number of segments, but it still won't be a proper circle.
     
  4. Nexxo

    Nexxo * Prefab Sprout – The King of Rock 'n' Roll

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    That is indeed the greatest problem with SketchUp. No biggie if your design is mostly straight lines and rounded corners (which can be segmented to such a high degree that for practical purposes they appear continuous curves), but if you are working with arcs and big circles, it's a problem.

    I use SketchUp mainly as just that --a sketch, a proof of concept.
     
    Last edited: 11 Jul 2014
  5. IanW

    IanW Grumpy Old Git

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    If you want to produce dxf files directly, give Draftsight (a free AutoCAD clone) a try.

    One problem though, Draftsight is not parametric.
    That is, you cannot change a dimension to change a line, you have to change the line to change the dimension
     
  6. GuilleAcoustic

    GuilleAcoustic Ook ? Ook !

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    I was going to suggest the same software. Great thing about DraftSight, it's available for Windows, Mac and Linux :D.
     
  7. Neogumbercules

    Neogumbercules What's a Dremel?

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    As an AutoCAD professional who has had to deal with dwgs/dxfs from other softwares I'll just advise you to get AutoCAD or whatever software is the "standard" in your industry if you can afford it. Far fewer potential headaches.

    My most recent nightmare was a 250 sheet project that I was stuck using converted TurboCAD files that were broken/corrupted in really annoying ways.


    Sent from Bittech Android app
     
  8. BD Hopkins

    BD Hopkins What's a Dremel?

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    Re: the circles, that's exactly the kind of thing I was hoping to discover, Flibble and Nexxo, thanks.

    Nexxo, I totally get that the concept proofing use for Sketchup. Sometimes you just wanna see if something will fit together. It might be worth the time investment of learning a new program, though, if it saves me the redundancy of having to make the design in sketchup and then again in another program.

    Ian and Guille, I'll check out DraftSight, thanks. Ian, can you expand upon why a non-parametric program is a hassle? I'm don't see having to make a new line instead of modifying the dimensions of an existing line to be much of a problem.

    You've illustrated a major concern I forgot to mention: my understanding is that CNC machinists will often give you a discount if you submit files in a format they can feed directly to their machine, precisely because it saves them having to do it from scratch or convert some mess of a file. I'd expect there to be different preferences at different CNC shops, but IDing the most common format will cover more bases.
     
  9. Neogumbercules

    Neogumbercules What's a Dremel?

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    Unfortunately I don't know what the standard for CNC machining might be as I'm in the architectural field, but if I had to guess I'd say Inventor or Solidworks would be pretty common across the board or possibly Siemens solid-modeling software which I can't remember the name of.

    99% of the job postings I've seen for mechanical drafting want Solidworks or Inventor users and of those 2 my anecdotal observation is that Solidworks is more common.

    Sent from Bittech Android app
     
  10. IanW

    IanW Grumpy Old Git

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    Yeah, I'm a Solidworks herder myself.
     
  11. BD Hopkins

    BD Hopkins What's a Dremel?

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    What is SolidWorks' native file format, and are there any issues converting to dxf for use in CNC machining?

    Inventor is listed here. Why choose it over AutoCAD for CNC machining? As you know, both programs are from the same company.
     
  12. GuilleAcoustic

    GuilleAcoustic Ook ? Ook !

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    From what I've read it's DWG (Autocad / DraftSight) and sometimes SVG (Illustrator / Inkscape).
     
  13. Neogumbercules

    Neogumbercules What's a Dremel?

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    The primary reason to use Solidworks or Inventor over AutoCAD for mechanical drafting is the tools. Those two are designed from the ground up specifically for modeling parts in 3D. AutoCAD can do it, but the tools are so much more robust in Inventor and Solidworks.

    Think of it this way: you could use a wrench to hammer a nail into a board, but you'd probably rather want to use a hammer.

    Sent from Bittech Android app
     
  14. IanW

    IanW Grumpy Old Git

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    Solidworks uses 3 file extensions:-

    sldprt - Solidworks Part
    sldasm - Solidworks Assembly
    slddwg - Solidworks Drawing

    But it can import & export a great many other CAD formats.

    DXF is not a problem.

    The main downside is cost - you're looking at around £5000 per seat & £1000/year subscription (support & updates)
     

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