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4236Re: DLP curing vs XY scanning laser curing

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  • jfrohwei
    Jan 4, 2012
      The reason for maybe using two LED lasers is that one is single mode.
      A single mode laser can give you a small beam that is less likely to
      diverge over distance, which is what you want with a galvo mirror
      setup, since the beam has to travel farther to get to the edge of
      the model as opposed to the middle. So this low power laser would
      be used for fine details.

      With a multi-mode LED laser module (and/or multiple LED lasers), the
      light is generated by several point sources, which gives you a lot,
      of power output, but the light diverges rapidly. Since the light is
      running through a galvo, you can't use a focusing lense to focus
      all of that light on just one point, because the distance to the
      fluid changes depending on the angle of the galvo. So instead,
      this LED laser(s) might be better for infill.

      The ideal (and what you might be suggesting?) is to use a varied
      single powerful single-mode laser (like 3D systems,etc), but those get expensive quickly. $$$$ for 354.7nm, $$$ for 405nm, $$ for 445nm,
      etc. 500mW 445nm DPSS are running about $250 on ebay right now.

      If you have a setup like Robhopeless has where the distance to the
      fluid is always fixed, a laser with a focusable lense might be

      --- In diy_3d_printing_and_fabrication@yahoogroups.com, "Michael Couch" <cmichaelcouch@...> wrote:
      > What about the ability to vary the intensity of one laser? Is this not possible?
      > Michael
      > --- In diy_3d_printing_and_fabrication@yahoogroups.com, "jfrohwei" <jeff@> wrote:
      > >
      > > --- In diy_3d_printing_and_fabrication@yahoogroups.com, "Bart Libert (EducaSoft)" <educasoft@> wrote:
      > > > I like your idea of using a galvo set, but can you please tell me what
      > > > laderdiode you intend do use on it ?
      > > >
      > > > A 445nm laser can achivieve around 1 to 1.5 watts of power when
      > > > properly cooled, but I didn't manage to get a nice clean focussing
      > > > spot at distances more then 3 or 4 inch away from the lens.
      > >
      > > I found out that the 3D Systems SLA-7000 model uses a "Dual-spot"
      > > laser. Fine beam for surface detail, wide beam for rapid infill:
      > >
      > > Small spot 0.23 - 0.28 mm (0.009 - 0.011 in)
      > > Large spot 0.685 - 0.838 mm (0.027 - 0.033 in)
      > >
      > > I'm thinking a fine detail single-mode blue laser, along with
      > > a high-powered multi-mode blue laser, pointed at the same
      > > galvo setup, might work for a dual setup?
      > >
      > > The 3D systems SLA-190, SLA-250, SLA-500, SLA-7000, EOS Stereos 400,
      > > D-MEC (JSR/Sony) SCS-1000HD, Envisiontec, Laser 3D SPL 1000/LSA,
      > > (others?) all appear to use galvos so any pictures of the insides
      > > of these systems would be golden. (in particular 3D systems...)
      > >
      > > References:
      > > http://www.3dsystems.com/products/datafiles/sla7000/datasheets/SLA_7000_system_rev_0204.pdf
      > > http://www.allbusiness.com/professional-scientific/scientific-research-development/158446-1.html
      > > "Rapid prototyping" By Andreas Gebhard
      > >
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