Printing Printers

I got 5 Nema 17 from Amazon cheap enough... not that I needed 5 (OK, I probably think I do).
Still they were cheap enough

Only need one for the DLP anyway, but I figured 2 is better than 1

We decided to push ahead with the DLP first, but the standard SLA is still going to happen. It will be used for very small, detailed parts if we can get the resolution good enough. Plus, honestly, the DLP is really simple compared... I know we can get it up and running quicker.

 

This one is what I started using.
Making a few changes (no mirror) but good guide.

http://www.instructables.com/id/DIY-high-resolution-3D-DLP-printer-3D-printer/

 

OK, we started construction of the frame/case/etc for the DLP as well as the projector mods.
Projector modified (remove UV filter and mod focus to allow for full-range focus).

Ordered the tray/bath pre-assembled (spare parts for an mVUe that we will use for ours). We also calibrated the focus for the projector (need to do this to know where to put it relative to the build bath and platform). So it will have 5"x4"x12" build volume. We could have gone larger (8"x8") but this is for high-res parts, not really large ones and it is not a high definition projector so this is a happy spot. The focal point is almost exactly 8 inches from the outermost lens.

As mentioned we will not be mounting the projector horzontilly and bouncing it off a mirror, rather vertically and directly into build bath. The horizontal approach saves a little build height on the frame -- don't care. It does mean we have to allow/account for the cables and how they route to the projector, but easy enough to leave some room for that under it.

Still waiting on the steppers and the threaded rods/nuts.
Also we will make the door out of lexan with a UV block coating on it.

 

I'll post a build parts list and total cost when done, best guess right now is under $300 for a decently sized DLP roughly equivalent to the mUVe 1.5 DLP (non-HD version).

 

Glass build bay, non-stick pads, couplers and stepper motors arrived.
Will be able to make more progress on the frame this weekend.

Really just waiting on threaded rods with nuts now... last part of consequence.

 

Bottom section done. The tricky bit was measuring the focus point from the projector to the correct spot (9 inches +/- 1 inch of 'tweak' for this projector) so that you know exactly how high to make the top of this box (from where the projector mounts in the center -- pointing up). This way it will be focused on the build plate which will sit on top. There will be 9 inches from the top of the projector lens to the inside bottom of the build plate (which is 1/4" thick).

Still have holes to cut for that and the top threaded rod frame to assemble/create and then a top cover. The brace/mount for the projector is shown, but is not yet permanently attached. Wanted to wait until we do the build plate and mount it so that we can more precisely mount the projector the first time.

 

And in the mail today, pretty much the last part we were waiting on. Only needed one, but have a spare.
Still have a few to manufacture (like the actual build plate).

 

Consensus seems to be that stainless steel is the best build plate. I think we have some in the shop, but if not I'll run out to a local fab/scrap shop and get some. Weld up the plate to match the rods and the glass bay.

 

Will be printing a 'cap' for the top of the threaded rod that will fill in the void between the slats and hold it in place at the top. Then cutting the hole in the base for the projector and attaching the build plate.

Apparently stainless steel is the preferred platform material so I'll get an 1/8" thick sheet and we will cut and weld that to make an arm and plate from the threaded rod into the build 'vat'.

The size of the resin vat is 8 3/4"x7 1/2" (by 2" deep) but the actual build volume I am targeting at 5 1/2"x4"x12" (roughly 12 inches--the usable size of the threaded rod). That seems to be the best focus size for the DLP projector we are using (X/Y sizes) at that distance (unless I make the base much taller). I'll probably cut the hole just a bit larger than the build size (6"x5" or thereabout).

Also got the jug O'MakerJuice in so once we get the build ready we can actually print.

Next we build the top of the 'case', some feet and start testing the printer.

 

OK, got the main mast done and even got to use some of the cheapo pink filament in the process
Makes a nice channel cap. Now we are building the arm and build plate. I am not going to build the entire arm and plate from stainless -- too heavy. Instead the arm will be 6060 Al and the plate will be the stainless (roughly 6x5) and there will be two of them separated by springs to allow for fine-tuning the leveling of the build surface.

[I know this has been slow, but Mon/Tues are my sons days off so that is when we fiddle with it.]

 

Tuesday update.

The arm from the screw to the build vat is done. There will be two stainless steel plates (cut from that 1 foot square you can see hanging around the photos) attached to this and the bottom one will be the build platform (it build upside down). It will be attached with top welded screws and springs to the top plate and that will be the fine level adjustment. The bottom of the bottom plate will be pristine, nothing coming through to block any of the build surface.

I do not even want to talk about how difficult it was to do those bends in that Aluminum and have it be level from top to bottom. It would have been easier to cut and weld (we originally planned steel -- which we could have done) but no TIG welder so no aluminum welding. We had to get inventive with a jig made out of square steel pipe and... nope! not going to go into that -- too soon.

 

So after a week delay we are back to it this weekend/today.

Had to design something to keep the arm/tongue for the build plate in-line as it moves from top-to-bottom on the lead screw.
I thought about using some wood molding to line the channel and direct the arm, but it would require rather precise work with a saw to make sure the arm stayed centered top-to-bottom. Instead we made an adapter for the arm that rides inside the channel to keep it in place and straight up/down. (pictures to follow). This seems to be perfect and leave only the wiring up of the electrical sides now. Mechanically it is done. A single Arduino (not even a mega--a leonardo or UNO would be fine) and a single motor controller on it will handle the Z and then the projector will be software driven as well.

As a note I will be building a 'shell' to cover the top out of 1/8" paneling or plywood. Then painting it black inside to really attenuate light leakage. There will be a lexan door with the laser shield cover over it to attenuate the light frequencies (uv below 500 nm) that the DLP uses to activate the resin with. Buying this stuff is pretty simple, comes in sheets already to stick to something (like glass or plexi).

 

This is larger than I would have guessed before starting. It is a piece of furniture at this stage
No worries. I will make room for it.

 

Did a test and the stepper runs it up/down without any problems and no wobble in any direction.
A little molding/firing strips to hold the build bay centered and it is time to mount the projector and other electronics next.

When we are done I will post the complete parts list, sources and costs along with models for the bits we printed. So far the most expensive bits were the build bay/tray, the resin and the projector.

in all honesty you could build this in a weekend or at most 4 days of solid work, we are just taking the slow route and doing it only on parts of days we actually have off together.

 

Not my arm, that is my son.
It did happen because of a bike wreck, but not the way you might think. A bit of a story there...
He broke his arm in a low speed wreck in the rain. No big deal...
All three of the bones.

They went in and put in steel plates and screws to hold everything together and then couldn't get the surgical incisions closed (the extra hardware took up too much room). The (idiot) orthopedic dr tried three different times (with three surgeries) across three months and in between kept the would open and sealed with a plastic surgical dam. FINALLY he did a skin graft and that took poorly (as you can see) and then sent it over to a plastic surgeon who offered to clean it up. By then he was sick of surgery (and associated pain and recovery) and just told them to leave it

It ain't pretty. You can see in the xray the outline of the staples they had to use to hold the plastic dam in place every time.

 

OK, actually had another bit if time today so woot!

Getting the projector and electronics mounted. The writing you see is from the back side of the paper we are aiming at, not from the projector. We will need a blank sheet to fine tine the focus once it is mounted.