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3523Re: [diy_3d_printing_and_fabrication] Re: I've got focus.

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  • Fernando
    Sep 4, 2011
      That is indeed interesting! Did you measure any minimum throw distances
      for that projector off the shelve? You may have published this already
      but you know how I tend to oversee things sometimes ;)
      My brother is thinking in building a 3D printer after me and I may want
      to indicate him as many parts that do not need tinkering as possible.

      Anyway, on my broken DLP, I try to be philosophical: I see this current
      build as a learning project, and there's already so much more I know now
      than I did 6 months ago. It's incredible when I go back to my notes from
      then, I was so naïve! I'm sure that for the second build for my brother
      all will be a lot more straight-forward.

      Today's take home message: don't mess with your light integration
      tunnel! And find a projector that keeps itself clean.

      On Sun, 2011-09-04 at 17:35 +0000, techartisan wrote:
      >
      > Bummer about your damage. Hope your back up and running quickly.
      >
      > This information obviously comes a bit too late....but for those who
      > have not yet purchased a projector...
      >
      > Most projectors simply run their cooling intake through a filter
      > hoping to catch dust....obviously this is not 100% effective....and
      > adds maintenance to the projector. Optoma projectors are designed in a
      > way that prevents the filth issues many other projectors have. Im not
      > certain the specific details of the air route...but they are
      > filter-less and maintenance free by design..I bought my projectors
      > new....and havent bothered to open them up...but I was told by a
      > service tech that the optomas he has worked on were very clean
      > internally. Just something to consider.
      >
      > --- In diy_3d_printing_and_fabrication@yahoogroups.com, Fernando
      > <spacecaptain@...> wrote:
      > >
      > > OK, damage limitation mode:
      > > I just bought myself another HP VP6121 projector for parts from
      > ebay.
      > > I will be more comfortable tinkering around on the projector with
      > the
      > > knowledge of having replacement parts to fall back upon.
      > >
      > > In the meantime, I will have to go back to the test rig for making
      > the
      > > initial resin system comparisons. This will all set me back
      > somewhat,
      > > but what's a kid to do...
      > >
      > >
      > > On Sun, 2011-09-04 at 18:42 +0200, Fernando wrote:
      > > > Oh dear...
      > > > Everything was going so nice and I have majorly fuc#ed up!
      > > > I was so happy because I had tweaked the lens assembly positioning
      > in a
      > > > way that the distortion was gone and I was trying out throw
      > distances
      > > > with the color wheel out of the way. Everything was just rosy!
      > > >
      > > > But then I noticed there was a band of dirt on the left side of
      > the
      > > > picture and I assumed there must have been a spot I missed
      > cleaning in
      > > > the optics. The only part I hadn't yet thoroughly cleaned was the
      > light
      > > > integration tunnel. In a projector that is a rectangular section,
      > hollow
      > > > (or solid) tunnel that catches the light from the lamp and carries
      > it to
      > > > the DMD module. So I went and used some lens cleaning fluid and a
      > cotton
      > > > stick to try and clean it.
      > > > The bad surprise was when the cotton tip came back out with some
      > alu
      > > > scales on it, looking suspiciously like mirror residue to me. So I
      > > > quickly assembled the projector back, switched it on and indeed,
      > the
      > > > image was almost completely gone!!! I cannot believe I just
      > destroyed my
      > > > projector just before the all important resin curing tests... I'm
      > so
      > > > frustrated right now I could burn the damn filthy projector in a
      > pyre!
      > > >
      > > >
      > > > On Sun, 2011-09-04 at 14:42 +0000, vrsculptor@... wrote:
      > > > >
      > > > > Fernando,
      > > > > I tried shimming the lens assembly out and got distortion.
      > Admittedly
      > > > > my shimming was on the crude side and may have been the problem.
      > That
      > > > > is why I ended up shimming the focusing ring. Your solution is
      > much
      > > > > better, if you can fix the distortion, as you have a variable
      > throw
      > > > > while mine if fixed.
      > > > >
      > > > > Please keep us posted.
      > > > >
      > > > > Roger
      > > > >
      > > > > > This is something I have been giving some thought and doing
      > some
      > > > > work as
      > > > > > well. While modifying my projector's optics, I have managed to
      > > > > forward
      > > > > > the optics module for about 2mm within the flange that
      > supports it,
      > > > > > which provided the possibility to focus at significantly
      > closer
      > > > > ranges:
      > > > > >
      > > > > > From stock, my DLP was able to produce a smallest area of
      > 230x280mm
      > > > > at
      > > > > > 530mm throw distance.
      > > > > >
      > > > > > After modification I am now able to throw images of
      > > > > > 135x110mm at 230mm distance
      > > > > > 200x150mm at 350mm distance
      > > > > > 230x280mm at 475mm distance
      > > > > >
      > > > > > This gives me a nice range of precisions and sizes to work
      > with and
      > > > > has
      > > > > > urged me to modify my printer structure to accommodate a rail
      > to
      > > > > support
      > > > > > the DLP. It's a pretty simple mod and this way I will be able
      > to
      > > > > adjust
      > > > > > size and resolution to suit my needs. The only caveat here
      > would be
      > > > > > calibrating dimensions from the 3D model to the print stage.
      > > > > >
      > > > > > NOTE: while fiddling around with the (incredibly filthy)
      > optics to
      > > > > clean
      > > > > > them up and shorten the throw I have introduced some
      > distortion. I
      > > > > will
      > > > > > have to carefully tweak around the positioning of the lens
      > module to
      > > > > > correct it.
      > > > > >
      > > > > > In the meantime, my In-laws have arrived for a vacation and
      > all the
      > > > > DIY
      > > > > > work is grinding to a halt.........
      > > > > >
      > > > >
      > > > >
      > > > >
      > > > >
      > > > >
      > > >
      > >
      >
      >
      >
      >
      >
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