Printing Printers

No, but if the new RAMPS exhibits the same issue I will.

 

More parts today another Arduino/ramps/stepper controller set (so, spares) and a full graphic reprap controller for the printer as well.
Soon as I get a break from printing, I am testing the scanner then (hopefully) this weekend back to working on the DLP I THINK i have enough spare parts now.

Getting the boxes from China is like mini-christmas because by the time it shows up I have totally forgotten about it.

 

OK, after a long down time of other crap getting in the way back to the DLP printer.

There is a dearth of information on DIY DLP at least at the practical level. Here is where we sit.

So at this point I have an Arduino Mega and a RAMPS with only a Z axis stepper driver and this works fine. Z motor steps as it should when commanded. Now, the BIG issue has really been software to slice and drive the printer and the projector. BTW: Sprinter firmware just so you know. GRBL is a hot steaming pile (tossed it) and Marlin has too much going on in terms of checks-and-balances that are mostly N/A for this style of printer (tossed it).

CreationWorkshop is the one most people had suggested, but it is pretty much dropped into a hole as far as development goes and when trying to control the Z axis it, just, doesn't. I know the hardware works because Simplfy3D will control the Z motor (can't use it with a DLP at present). Yet a RAMPS with EVERY axis (and both extruders) having stepper drivers and stepper motors simply doesn't respond at all when trying to manually control things in Creation Workshop (tossed it).

Slic3r (the current stand-alone build*) has a mode where you can tell it there is no extrusion involved an and put it into SVG mode. It will then generate the sliced layers as SVG files for projection onto the build vat. Pronterface UI has the ability to handle delivering the SVG to the projector and processing the (minimal) GCode for the Z axis. We are experimenting with this combo now.

All that is left is to mount the electronics into the cabinet and wire in the Z home and Z Max limit switches. Then assemble a cover (with a door) for the top and we are good to go. I almost (but not quite) regret not doing the SLA first since it will use much the same software and doesn't require a lot of re-think.

* the version included with Repetier host either doesn't do this or it is hidden by Repetier.

 

Frustration levels have been rather high on this and I almost see the reason to spend the money and just buy one
(almost) It got personal however so now WE WILL GET IT DONE.

 

OK, I can confirm that Slic3r will generate an SVG. Pronterface will load and then go into 'SVG' mode where it will display these on the projector screen -- one layer at a time (and the Z stepper spins when it should -- it even overshoots and compensates by going back down a little to agitate the makerjuice).

Some fiddling with layer times will be needed, but this is working so time to do the final assembly.

 

Only gripe I have software-wise is that pronterface is clumsy on full-screen control.
The projector screen needs to be full-screen and limited to JUST the stuff you want the resin exposed to.
Making that happen is awkward and we had to essentially make the primary screen the project screen to get the full-screen working correctly.

Even then a shutter is clearly going to need to be an add-on we do right up-front. There is no way (or no easy way) to do this otherwise.

 

Front door still to be done. It will normally NOT be used as there will be an access hole for the tray and a view port covered with the Red film.

 

Top section will be painted black inside and light-tight.

 

and there it is...

 

(why yes, that IS a Total Wine baggie... a crucial component)

 

Got the top just about finished and will post functional pictures in a few. We bought the build vat from http://www.muve3d.net/ (I think I mentioned that earlier) and we were/are building the build plate out of stainless, but as a safety/fall-back we ordered the aluminum build plate from http://www.muve3d.net/ as well (just in case).

 

steel is a better plate material than aluminum, but the difference is not huge. If our steel plate is close enough in tolerances we will use that, but I was concerned about the tolerances (which have to be very close). And like their build vat the plate is not crazy expensive (and comes from a working style printer)

 

OK, pictures. Top section done, blacked out, foam-strip sealed. The from panel is hinged and will normally be how you access the printer.

The small door is a cover for a viewport that will be sealed with the Red-Anti-UV plastic light filter. That way you can see in, but the UV stays out. That small(er) door opens/closes to completely seal that.

Stuck my head in and had a flashlight run around the seams to make sure it is light-tight inside. Also got the arm finished where the build plate will mount and it correctly lines up in the build vat. That is the build-plate we made, I will mount the one we ordered to the same arm. The tolerances are not quite where I would like them on that steel plate. Notice the top plate is spring-mounted to the build plate allowing that to completely be manually leveled.

Just need to paint he silly thing some color and then finish the electronics wiring in-place (it was all tested on the bench).

 

All that remains of the build is to seal the side bottoms with black cloth and mount the projector and electronics boards (and fans). We already did a test mount for the projector so the frame for it is correctly aligned.

 

Whew! Yes, the past two days have been a lot of tinkering

Finally feel confident that it is light-tight so we are ready to mount in the electronics an start serious testing.

I used the reprap calculator and determined with that leadscrew we need to set the Z steps to 1600 steps/mm (M8 2mm pitch). I'll edit Sprinter and reload that.

We bench tested the boards with the one stepper driver in place (Z) and using Sprinter with repetier and pronterface it 'seemed' to be behaving correctly.

 

So, recent evenets. Box painted and moved inside. Projector mounted.
We bought the build plate from the same people we bought the build vat from (http://www.muve3d.net/). Just to be certain that is flat and aligns with build vat.

Next is to wire a servo to open/close a shutter over the projector lens. It is a flat piece of thin carbon fiber left over from my battlebots days being cut and repurposed as a projector lens cover. About 5 inches across, teardrop shaped (pictures later). Mounted to a servo on the projector it will rotate 180 deg. to cover and uncover the lends as needed.

The servos have to be wired to the RAMPS on this block:





and are numbered 0-3 (4 potentially). Also notice the jumper on the right-had side just below where the servo is connected. That jumper by default is the other way and this is not good. It needs to be positioned the way you see it to provide power to the servos...

Then in Marlin you have to enabled them (look in CONFIGURATION.H):

*********************************************************************\
* R/C SERVO support
* Sponsored by TrinityLabs, Reworked by codexmas
**********************************************************************/

// Number of servos
//
// If you select a configuration below, this will receive a default value and does not need to be set manually
// set it manually if you have more servos than extruders and wish to manually control some
// leaving it undefined or defining as 0 will disable the servo subsystem
// If unsure, leave commented / disabled
//
#define NUM_SERVOS 3 // Servo index starts with 0 for M280 command

Marlin supports the servo commands which is why we used it.

That last line is normally commented out, you remove the comment tag so it actually gets used.
Trust me, you do NOT want to forget this or it will happily ignore all of your servo control commands and you tear your hair out.
(not saying we spent an hour chasing that problem, but ALIENS).

In the startup GCode you use this (or anywhere in the GCode that the slicer want to unblock the light):

M42 P0 S255

and

M42 P0 S0

swings it back to block the projector.

Nearly ready to start trying to print. We have bench-tested the electronics and firmware. The cabinet is ready.
Just need to mount the sparky bits and hook up the computer and projector cables.

Then the process is :

Slice with Sli3er, export as SVG then load that into Pronterface for 'running' the print.

Will need to do a crapload of fine tuning with exposure times and so forth.

 

I am buying a wig so that when I rip hair out ... it ain't really mine.