Framing and Mounting

Aluminum extrusion frame assembled

The frame pieces from Misumi came in. The extrusions were cut quite evenly, and assembly took an hour or 2. The nuts I'm using are a bit of a nuisance because they have to be slide into an end, which often means loosening a piece or a bracket to insert it. The vertical brackets also need care when loosening the screw, because if the screw comes completely out, the nut slides under the top of the next bracket. However, with all the adjustments I'm making as I go, I'm glad to have gone with the extrusions.

Tap and die set for making threads in the holes of the aluminum plates

The actuator I acquired has mounting holes in the table, but they run close to the supporting smooth rods. I needed to make some threads with a tap and die set. After figuring out which tap to use, I had to go back to home depot to get the correct screws for mounting the lift.

Electronics mount for the power supply, Raspberry Pi 2, and Big Easy Driver

These 2 plates will hold the electronics. These plates are 1/8" thick, which is not quite thick enough for the 10mm long screws. I needed some M5 washers to match the trusshead screws I'd ordered from Misumi for the aluminum extrusions. After that, I just measured and drilled.

Projector mounts

I wasn't sure what aluminum shapes I would use to mount the projector or the electronics. I'd imagined using a plate for the projector, as some of the commercial mounts for it showed one. A plate would require precision drilling, which I don't have, and wouldn't be very adjustable if the projector didn't align straight down. Instead, I used 2 aluminum angles to mount the "top" and "bottom" (with respect to my frame) of the projector, which allowed for less precision.

I took the projector into Fry' Electronics to find the mounting hole size. Turns out the projector uses M3 screws, which seem too small for a 6-7 pound projector. Even with washers, I don't want to be moving the printer with the projector mounted. There is a larger mount hole, but I am not sure the commercial mounts use that hole either. I may remake the projector top mount.

The projector mount would have been easier if I had calculated the washer thickness. Since I forgot them, I had to enlarge the M5 holes with a dremel tool, which was tricky.

Aluminum for the lift

The lift assembly took much more time. I found a local metal supplier with a warehouse full of metal shapes. I used their "remnant" section to find quite inexpensive aluminum pieces. I have access to an abrasive saw and an aged drill press, though you might be able to make the holes with a hand drill.

I made quite a few holes in the lift plate to allow resin to flow without mixing. Others have used perforated sheet, but I wanted some support and a flat lift. I still need to trim it down to about 8x6" to fit a smaller vat.

The lift size directly affects my print area. Top-down printers have a distinct trade-off between the print area and the cost of resin waste. The larger I make the lift, the larger the container, and the more resin I need to pour to make the initial thin top layer of about 5mm. At $55 a liter, I do not want to be wasting much resin after a print.

Actuator mounted

The actuator was easy to mount after finding I had access to a drill press. I disassembled it to be able to drill the back plate, mounted the back plate, and reassembled the actuator on the frame.

Lift and Projector Mounted

Once I managed to get my pieces mounted onto the frame, I was excited to see the projector light up the lift. I wasn't sure exactly where to put the lift relative to the projector, and had guessed about 1 ft. between the verticals of the extrusion frame. I needed to bring it together about an inch to center on the lift. It looks quite square, though I need to check it with a real square once I get the electronics fully mounted.

Current Development Obstacles

Finding a vat container is proving tricky. I'm looking for a square container about 8x6" made of HDPE (the material the resin bottle is made of) with a lid. I might be able to use polypropylene, though it isn't UV resistant, not that I'm using that much UV. I've looked at paint buckets, foot baths, dish tubs, rubbermaid commercial food storage, over-sized glass vases. I'm going to keep searching, since the vat will significantly affect the overall cost of the resin.

The actuator movement of 4" is not sufficient, but a longer actuator costs quite a bit new. I'm looking into lengthening the rods and back support plate, so I can lift the actuator completely out of the vat. The trickiest part will be back support plate, as the top plate screws have a routed trench in the back plate.

What I Learned

• Ace Hardware is much better for finding and buying screws. Also, much more helpful.
• Taps create much aluminum dust. If screwing 2 plates together and threading both, be prepared to separate the plates to remove the dust before finally attaching the plates with the screws.
• Making aligned holes is easier if the first hole gets threaded and screwed.
• Keep in mind the washer spacing!