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RE: [diy_3d_printing_and_fabrication] Polygon mirror scanning based 3D printer

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  • Paolo Velcich
    I may be completely wrong and my idea could be not practical, but : what about adding a moving mirror coupled with a collimating lens, just like on the laser
    Message 1 of 132 , Jun 2, 2012
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      I may be completely wrong and my idea could be not practical, but :

      what about adding a moving mirror coupled with a collimating lens, just like on the laser cutting machiones ?
      Sync to the prismatic mirror from the printer ?

      This way you would be sure 100% about the planarity and focusing of each pixel.

      Such a light assembly, driven by a belt, could have decent speeds.


      Paolo

       

      From: diy_3d_printing_and_fabrication@yahoogroups.com [mailto:diy_3d_printing_and_fabrication@yahoogroups.com] On Behalf Of Graham Stabler
      Sent: sabato 2 giugno 2012 21:17
      To: diy_3d_printing_and_fabrication@yahoogroups.com
      Subject: Re: [diy_3d_printing_and_fabrication] Polygon mirror scanning based 3D printer

       

       

      Jon, 

       

      What sort of scan rates are we thinking here?  We are assuming around 10000 pixels per scan? 

       

      If you precompensate your part will have the right dimensions but less detail at the edges I guess as pixel density decreases and perhaps some overlapping in the middle.

       

      Graham

      On Sat, Jun 2, 2012 at 5:49 PM, Jon Elson <elson@...> wrote:

      The corrector lens gives quite accurate dot positioning over the whole
      scan. The electronic correction requires the pixel clock to vary,
      with very fine frequency steps, over the sweep. It could be as much as a
      10 - 20% frequency change from edge to middle, although the
      current crop of printers probably are much less. I really have no
      idea how you do this without using clocks at microwave frequencies
      in the synthesizer. I know it would be extremely difficult to do with an
      FPGA.

      You could pre-compensate the image and have the printer just plod along
      at constant pixel rate, and maybe this would work fine. Maybe this should
      be called Software Correction, as opposed to Electronic Correction.

      Jon

       

    • kafian
      Hi Mark, Solarez resin for 3d printing is $254/gallon which one are you using? http://solarez.com/productsnew/productsnew/uv3d_printing.html Jack
      Message 132 of 132 , Aug 17, 2012
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        Hi Mark,
        Solarez resin for 3d printing is $254/gallon which one are you using?
        http://solarez.com/productsnew/productsnew/uv3d_printing.html
        Jack

        --- In diy_3d_printing_and_fabrication@yahoogroups.com, vrsculptor@... wrote:
        >
        > Graham,
        > I see a couple of big advantages to this over DLP.
        > 1. Resin is cheaper. You can tune LED to be compatible with cheap (Solarez @ $51 gallon) epoxy resin. This is probably a factor of 4 cheaper than DLP resins.
        > 2. Size. Legal size (8.5x14) models are within capability of print engines.
        >
        > As you pointed out it is slower but I'm not sure that is an issue for a lot of us.
        >
        > Roger
        >
        > > I also think we need to be careful not to forget that DLP style printing is
        > > exceptionally fast compared to just about all other forms. The layer time
        > > our uprint if you did the whole build area is: go for lunch. And lets face
        > > it if we get it to work at all we could have a homemade 3D printer with an
        > > A4 work area and high resolution for very little money making parts that
        > > could not be made without a 3D printer.
        > >
        > > 0.1mm is quite a thick layer compared to the 20um we have talked about, so
        > > really that might be considered the time for 5 layers?
        > >
        > > I have a question John, how on earth do we measure the
        > > layer thickness's when we test? Build a tiny 3D printer that just prints
        > > blocks (let laser shine through a mask on the vat bottom) then look at the
        > > block. I've been quizzing Michael about similar issues on his kick starter.
        > > All I know is I won't be using my callipers to measure 20um.
        > >
        >
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