Printing the parts

Almost every structural part of the machine is printed, and printing is the longest job in the build. Start it before the rest of the parts arrive.

Every printed part, its STL, its filament weight and its print time are on the parts calculator. Set your layer count there first, because that is what decides how many of each part you need.

Filament

Print the parts in PETG or ASA rather than PLA if the machine will stand anywhere in warm or hot environments (in- and/or outdoors). PLA softens from around 55 C, and the printed gears the steppers drive through go first. The temperatures both materials hold are on the Hardware overview.

The printer

The parts are designed to a 256 x 256 mm bed. Nothing in the catalog is larger than that, so a bigger printer buys you nothing here. A smaller one means some parts you cannot print at all.

The machine needs 107 different printed designs, not counting the bins, which are optional and which you can also cut from cardboard.

• Bambu Lab A1, P1S, X1C, 256 x 256 x 256 mm: all 107.
• Prusa MK4S, 250 x 210 x 220 mm: 97.
• Creality Ender-3 V3, 220 x 220 x 250 mm: 97.
• Bambu Lab A1 mini, 180 x 180 x 180 mm: 88.

A smaller bed loses the largest parts: the feeder's stators and rotors, the interface plates, the Lazy Susan base. Several of those are needed four times over, so it is not one awkward part.

If your printer cannot do the whole set, print what it can and have the rest printed by somebody else or by a print service. The parts calculator has the STL for every one of them.

Calibrate the printer first

Some parts fit against something else with almost no room. The external brackets clamp around the 2020 extrusion, bearings press into printed seats, and heat inserts go into holes sized for them. A printer that is slightly out prints those too tight or too loose while every other part on the plate still looks fine.

Run the printer's own calibration before the first plate, and run it again when you change filament or nozzle. Bed levelling, flow ratio and pressure advance are the settings that move a printed dimension, and both Bambu Studio and Orca can test flow and pressure advance for one filament in a few minutes. Dialling those in once is worth more than any profile you copy from somebody else.

Print each part the way the file comes

Almost every STL is already sitting the way it should print. Drop it on the plate as it is and slice it. The few parts that have to be turned say so on their card in the parts calculator, under Print orientation, and that line is the only reason to turn one.

• Do not use auto orient. "Optimize orientation", "auto rotate" and the orient tools in Bambu Studio, Orca and PrusaSlicer will lay parts down on a different face. The face a part prints on is a design decision that is already made, and changing it is how a gear tooth or a bracket arm ends up printing across the layer lines and snapping in use.
• Moving a part is fine. Turning it over is not, unless its card says so. Sliding it around the plate, dropping it onto the plate and spinning it flat (around Z) all leave the printing face alone. Anything that tips it onto another face does not, so only do it where the part's Print orientation line tells you which face goes down. The Orange Pi housing's four walls and its roof are the parts that carry one today.
• Parts import off centre, and some import below or above the plate. They are exported in the coordinates they occupy in the machine, so the slicer puts them where the assembly puts them. Move it onto the plate and carry on. That is normal and it is not a broken file.
• The NEMA bracket needs a spin. It is 255.9 mm across as it comes and an A1 bed is 256 mm, so it slices with no room for a brim. Rotate it about 25 degrees flat on the plate and it clears with about 28 mm to spare.
• Auto arrange is fine for packing several parts onto one plate, as long as it only slides and spins them. Check the plate afterwards and make sure nothing has been turned over.

If a part looks like it wants turning and its card says nothing, do not turn it. Ask on Discord first, because a part sitting wrong in the file with nothing on its card is a fault worth fixing for everybody.

Supports

Supports are off for almost everything. A handful of parts need them, and the parts calculator badges each one Supports. Check the part there before you slice it.

Turn support on for those, normal (auto), with the overhang threshold at 10 degrees. That is what the filament weights on the calculator assume.

For everything else, look at the sliced preview rather than the warning. Some parts have small overhangs that make a slicer complain, and they print fine. If you can see a feature that genuinely starts in mid air, switch support on for that part and reslice.

Check before you press print

A plate of these parts can run ten hours or more, so two things before you start it.

1. Check the slicer's time and filament against the calculator. If your figure is wildly different, something in the profile is not what you think it is.
2. Print one before you print twelve. This matters most for the External bracket (side), which is a tight fit around the 2020 extrusion and is badged Tight fit on the calculator. Print one, fit it on a piece of extrusion, then commit to the set.

Print settings, at the top of the parts calculator, is the profile those figures are sliced with: printer and nozzle, layer height, infill, supports, skirt and filament.

There are also ready made build plates for some of the repeated parts, as 3MF projects you open and print. They print on textured PEI, and each part row on the calculator says which plates it appears on.

Planning the print

The filament and hours for a whole machine, and what the hours really mean once you count plate changes, are on the Hardware overview. The short version: print early, fill the plate, and print in the order you build so you can start assembling long before the last part comes off.