King Cheezbot

The amazing, wonderful 3D printer project that's really not going too well unfortunately: ALL HAIL YE MIGHTY KING CHEEZBOT.

It's big, it's heavy, it's yellow, it's behind schedule and way over budget. But I think it'll be pretty cool. The project has served as the excuse I needed to join the labs, and I'm hoping that the tools at the labs and insight of other members will help me to finish it.

It's based on a design called Hackerbot: I found it on the reprap wiki and sourced the parts. Later on it was offered as a kit which would have made my life way easier.

http://reprap.org/wiki/HackerBot

https://opensourcehardware.it/en/home/61-hackerbot.html

My decision to build Hackerbot was based on a few design factors I felt were desirable:

• • Non-coupled Cartesian axes (not Deltabot, not H-bot, etc., so if a belt slips or a motor misses a step, I know which one it was.)

  • Bowden feed for reduced print-head inertial mass

  • Symmetrical, Ultimaker-style gantry (Y axis does not have more inertial mass than X axis...   And yeah I should have just bought an Ultimaker)

  • Enclosed build volume (for temperature control)

  • T-slot aluminium construction (for general hackability, mounting accessories, or reworking or repurposing the whole machine structure in the future if I feel like it)

My build is based on the early-2014 version of Hackerbot, but with a few changes:

• • Added 10cm additional vertical build volume

  • Replaced single front door with twin removable doors

  • Altered control panels to mount in the front panel instead of 3D printing a box for them

  • Redesigned or modified 3D printed elements, such as filament driver assemblies and end-stops.

  • Added Pi + HDMI touchscreen display + front panel USB for Octoprint as well as the full library of Infocom text adventures.

Miscellaneous fuck-ups so far:

• • When sourcing the parts I used a 2011 Misumi print catalog because I found their website obtuse. It turns out their pricing has changed significantly since 2011, so the initial parts order was quite a bit more expensive than I'd thought.

  • I powder-coated the metal hinges: but was unable to remove one of the plastic inserts in the hinges before powder-coating. (So the insert melted...)

  • Ordered wrong-size aluminium parts for door, so the door wouldn't close properly. (Ordered replacements)

  • I suck at tapping threaded holes, so various parts were compromised or replaced as a result.

  • I have wasted loads of acrylic either by laser-cutting the wrong pattern, or using the wrong laser settings and failing to cut through. (And the panels are big enough that in many cases suitable replacements aren't readily available.)

  • I accidentally connected my +24V DC supply to the frame and powered on the machine (Deeerrrrrrrpppp...  BANG! Magic smoke) Fortunately this appears to have only fried the USB circuit of the machine's RUMBA control board, as that was the only other thing connecting 0V DC to ground at the time...  But various other failures have been cropping up since then so maybe not.

  • I generally got in way over my head...  But that's the idea, too, I wanted to build this machine to learn how to build a machine like this.

Specs:

• • Dimensions: 510x510x750mm

  • Weight: Approx. 25kg

  • Print area: 300x300x350mm (Roughly; it might be more like 290x290 depending on end-stop placement, etc.)

  • Dual extrusion print head, Bowden drive system using 1.75mm filament

  • Motor step size: 0.2mm on X/Y axes and 0.01mm on Z axis. (20 tooth x 2mm sprocket, or 2mm lead screw revolution, divided by 200 motor steps per revolution.)