weekend work

I received the misumi order Thursday of all that beautiful extruded beam, and promptly set about procrastinating while I was deciding how to build the box itself.


So I cut up 4 beams into a set of  various lengths and set about building a frame.

I realized once I had a basic setup that the linear path was going to drive any freshly printed model right into the lens.

I then decided to try the mirror method.

Following the guide on calculating mirror distance I came up with a number for my height.

Cut some mirror

and spent some time re-arranging my beams to get various configurations looking for the right height/width combos with my now cut beams.

Even more on lenses and optics....

After some discussions on irc with some knowledgeable people in #dlp3dprinting

There is no need to modify a working projector. Make sure you have a projector with 3k lumens or more and you can either use a mirror ala this instructable  or with closeup lenses from cameras. The b9 creator I think it was is using a +4 closeup lens for their unmodified projector.  77mm lens packs with 6 assorted lenses can be had for 12$

At this point if I want a better DLP I dont need to worry about destroying a projector I can just use a good one and when not printing I can watch tv :) although i seriously doubt I would waste valuable bulb life on a movie.

I know my eyes are particularly sensitive to uv, its both inherited and sensitized from years of contacts and a little laser surgery. Because of that I've been waiting on some glasses but I'm not the only pair of eyes wandering around and while I have been making sure kitty is out of the room when I fire up the UV I thought I should take a look at case options for containing the near UV I'm working with. A little looking on line and I see tap plastics acrylics block a decent % of UV so I wandered down with a 405 nm light source and something fluorescent I found the amber worked well.

bare 405nm 9 bulb flashlight pointed at paper with highlighter

camera behind filter light source in front of filter

This picture shows that fluorescence is a re-emitted light its visible through the near UV filter

Light through filter, camera unfilterd

camera and flashlight behind lens, the brighter spots are reflections from the shiny surface

Here you can see that light has made it through but unlike the pic 2 above there is no fluorescence thus the light penetrating the filter is no longer 405

More on the lens

I wasn't happy with the way the lens focused... that's not it... I didn't have a build are big enough to build the kind of things I was after. so I took the lens unit out and messed around a little bit. It seem that by moving the built in optics forward around 2 mm in my case I was able to focus the pixels almost exactly to .1mm. Actually between the throw and focus I can get a variety of resolutions. From about 44 mm X 33 mm (.044mm per pixel) all the way out to 110 mm x 82 mm (.11mm ppx).

The macro lens I had is unnecessary.
I will need to make a collar or something to set it in place properly there's a little bit of wiggle with the screws in place and it would be nice if I could adjust it. The depth of field? if that's the right term is very short it is only in focus within a very small distance, and the throw length? distance from projector to the focused image is now 16.5cm when zoomed out and 9cm or so when zommed in

in place with the 2mm offset
Much damage to the case from trying to fit unneeded optics

The optics unit

The dmd and light prism

The optics unit part way in place

A focusing lens

I decided it was time to work the optics out.

Upon opening my projector I see it has this nice sealed lens system leading into the light path The tiny lens and focal point made me not want dig inside. I happen to have a few old camera lenses laying around an after a little fiddling found the macro lens that worked.

random macro lens from a view camera

The iris mechanics unscrewed which was good
I needed to get the lens closer to the aperture

I notice the light does not exit my projector in a level manner its angled "up" at about 15 degrees this meant the lens needed to be fitted on at an angle.

Hung loosely in place just to get a rough idea

6 cm x 4.5 cm the dark edge is the camera taking the pictures shadow notice the pushpin in the upper left.

A couple of good links that will make everything easier...

Software that slices objects for dlp and lcd type systems by PacManFan

and A group of people doing various versions of the same thing I am BuildyourownSLA

I got my connectors and installed them on to the steppers, which I then attached to the board, and wired it all to the power supply with a fan.

Duino power and steppers next to projector

I mocked up a light source and by that I mean I pointed a 3w white bike light into the light path. I had some trouble getting the projector to find an input signal. Eventually I decided to just unplug my primary monitor and leave the projector as the only display option. The computer forced a vga signal and poof I had a display

#reprap projected onto white sheet of paper
form a modified Acto dlp Projector
powered by a bike light

OMG yet another easy way to get where I'm headed, TY Diyouware!

http://www.diyouware.com/

These guys have taken a dvd player mechanism and hacked it enough to hook to an arduino.
The current incarnation is a PCB printer, something that will sensitize a uv photoresist. They only need to add the z motion of a keyhole type SLA and they've got an ok resin printer. .1mm seems to be the current resolution available, I think that's a mechanical function of the frame and steppers and better mechanics will allow higher resolution.

I've ordered a few of the 7$ laser modules and am looking into getting the pickup board made. since they provide the files.They are running it off an ardiuno uno, and I'm pretty sure I'm gonna want to upgrade the core to a 2560 just because the full version of marlin will install. so i might need to "design" a new shield thankfully that's barely within the scope of my abilities... gotta love software...

eagle cad

gonna see if I can't borrow a ramps schematic and merge it with their shield schematic.

DLP Projector Now ready for any light source

I have an Acto AT-X51 dlp projector...


 This is a perfect projector for my purposes, it has a 1024x768 dlp chip, and they no longer make lamps for this projector its super cheap. After rather a bit of disassembly and tracing wires around I found the right thing to short to prevent the MB from checking the lamp. its actually accessible right under the keypad.

notice the solder blob on the first two pins of the "ballast"

 Next I see this model knows up from down so I need to disable the switch, on the other side of the same board so you dont have to remove the board it to short it.

The odd little can with the silkscreen sw1 Disabled by shorting with a solder blob
Shorting it makes the projector think it is upside down. desoldering it would keep it right side up

as well as the color wheel because this is to be a UV setup and the color wheel gets in the way. well there's an encoder and I cant remove the setup so its just breaking the colors off the wheel.

Broken color wheel glued out of the way of the light tube.
Backside of a 3w led star base

The color wheel has an encoder attached that it cant be removed since the projector uses the encoder for color syncing.