Thinking about making one of these things for yourself?

To get started with starting to get the getting started started to push out sufficient information to inform doing that...

...here's a rough rundown of parts to collect for the CNC mechanics. At this point I've iterated the XY stage design more than the Z axis so I can be a little more specific about that.

 ̶ ̶I̶'̶m̶ ̶w̶r̶i̶t̶i̶n̶g̶ ̶  I wrote about slicing and printing the printed parts separately. And the assembly process (forward-looking statement ahead...) as a richly illustrated and procedurally detailed Instructable -- which I expect will be not nearly as intricate as for the laser-cut version.

At this point, the scope of this info here includes the CNC mechanics (X+Y & Z axes), which will work in a very simple frame. Writing up stuff to stuff into the more fancy integrated desktop enclosure to follow.

Stuff

• PLA
  • 250g for XY table
  • haven't weighed Z axis or (optional) fancy enclosure accessories
• bearings
  • 10 x LM6UU
  • 6 for X+Y; 4 for Z axis
  • generic "brands" appear to be all the same inconsistent quality; buy more and select
  • MSM bearings appear to be a clear step up from generics for not so much more coin
    • (2 x 8 pcs cost <$1 more than 3 x 4 pcs at 16 Sep 2023 pricing)
  • "real" parts cost real money, like USD20 each
• rods
  • 6mm "linear motion shaft" (typically ground, hardened, and plated carbon steel)
  • 6 x 120 mm for X+Y stage
    • buy pre-cut to length e.g. here (2x 4pcs shipped to US for $13.62 -- 16 Sep 2023)
    • or buy/find longer, e.g. 2 x 400 mm. and cut to length
  • tbd 2 x 165-200ish mm for Z
• XY Motor+leadscrew
  • two; one each for X & Y axes
  • nameless generic product, often including "80mm stroke" in description
  • searching "stepper 80mm stroke -nema" seems effective: google, duckduckgo
  • with white plastic slider not bra$$ $lider and linear bearings
  • there are two plastic slider types; don't care
  • there appear to be two wire types
    • 300 mm wires with 2.54 mm pitch connector
    • 200 mm wires with 2.0 mm pitch connector
  • the v0.9.0 STLs have details that favor the 300 mm/2.54 mm wires/connector
  • some sellers like this one show drawings of two types A & B
    • but I've received a "type A" unit with type B wires/connector, so might have to ask if care
  • printed backlash adjuster ("bladj" STL) to be installed like this (different details; same procedure)
• M3 tap
  • for printed backlash adjusters ("bladj" STL) for X & Y motors
• paperclips
  • aka backlash adjuster locking springs
  • two
  • or other springy bendable wire ~0.8 mm diameter
• Z motor(s)
  • ye olde 28BYJ-48
  • 5V
  • one motor
    • works
    • but I'm running mine too hot for a PLA pulley (using PETG)
    • possibly could reduce drive current enough for PLA but I haven't tried
  • two motors
    • cheap insurance against some free-fall failure modes
    • more likely able to run cool enough to use PLA for pulleys
• zip ties
  • 4in, 18lbs
    • how does the rest of the world specify cable tie sizes?
    • tie straps ~2.5mm wide, ~1mm thick, at least 100mm long
    • stronger 4in ties exist but I think the straps will be too wide/thick
  • square heads (no gussets between head and strap)
  • many
    
    • current count: 36
    • get more for trial fits, waste, dis/reassembly, etc.
• printed zip tie tools
  • tool STLs to print
    • "tietoolshort" -- short tool for short tie strap tails
    • "tietooldeep" -- long tool for deeply recessed tie heads
  • many of the tie heads are recessed below surrounding surface
  • need a way to hold down tie heads while pulling tie straps tight
  • my current practice is ... not refined
    • better ideas welcome!
  • cable tie tensioning tools exist but
    • I don't have one
    • all that I've seen pictures of assume free clearance around the tie head
• limit switches
  • three (XYZ)
  • search "KFC-V-307" or "Camera A15"
  • example
  • 6 x small screws
    • I have some scavenged 1.6 mm x 4.8 mm x 0.5 mm pitch
      • pitch is more coarse than coarse M1.6 and I haven't found a source for any similar
      • 1.6 mm is just a hair big for a mild interference fit, which is fine, but suggests 1.5 mm would be more "correct"
    • #0-40 x 3/16 in. thread-forming screws for plastic look like a good fit and are widely available from many vendors -- in lots of 10,000
    • McMaster-Carr lists #0-42 x 3/16 in more accessible quantities, but still kinda spendy with shipping.
    • #0 diameter is 0.060 in. which is 1.5 mm
    • found a source? please say so.
  • wire e.g. 24AWG speaker wire, heatshrink, etc.
    • X: 25 cm (10-ε in.) between switch body and connector housing
    • Y: 13 cm (5+ε in.) between switch body and connector housing
    • Z: tbd
    • cables made to length because cable management designed into the XY stage assumes:
      • wires routed internally to 2p "DuPont" connectors in the stage base
      • 2p extension wires to the controller
      • so the interconnect can disconnect at both ends -- for sanity in dense packaging
    • gender reveal?
      • I'm currently using female connectors on the switches because the Protoneer-designed CNC shield uses male headers and using connectors that could connect to the controller seemed like the thing to do -- plus M-F extensions where needed
      • but might change to male pins on the switch side to avoid waving bare input pins (or motor power pins) around when unplugged -- then F-F interconnect required but nothing lost with connectors fixed in the mechanics that physically couldn't connect to the controller anyhow
        • but the F 0.1in connector on 300 mm motor leads will still be F
          • which is maybe another reason to design for the 200 mm / 2 mm leads instead
            • and inline M connectors for the 2mm JST-PH F connectors exist (unofficially? i.e. appear to be not a JST product)
            • and here's two PH-connected motors for <$17 (16 Sep 2023 pricing)
              • mumble foo
• electronics
  • if you don't already know/have what you want to use:
  • ~USD10 complete kits of (clones of) Arduino UNO + Protoneer CNC shield + Pololu A4988 stepper drivers exist
    • example (whoa: $2-$5 "welcome deal"s for new AliExpress users; dunno if that's real or not)
    • not DRV8825 for this low-current application
      • but STSPIN220 drivers would rock for this low-current application... I think... maybe
    • four motor drivers if you think you might want two Z motors
      • i.e. not a Nano/v4 kit for three drivers only
    • note all 0.1" male header pin connections, so plan for corresponding "DuPont"-type connectors
• wiring
  • if you use a Protoneer-type CNC shield and get "type A"-wired motors then connections will be all M & F "DuPont" type wire terminations, which might be a welcome simplification, but...
  • If you're aren't ready to make up "DuPont"-type terminations, then maybe get a bunch of M-F pre-crimped 30 cm & 50 cm wires like this and 4p & 2p housings
  • soldering wires to chunks of 40p header strip looks cheap and easy, but I haven't found a way that isn't fragile.