3521Re: [diy_3d_printing_and_fabrication] Re: I've got focus.
- Sep 4, 2011OK, 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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