Hardware

The machine is still in active development. Pages under Assembly and Electronics range from steps verified on a built machine to unverified first drafts; each page states its own status.

Before you order anything

You can build this on a bench. It does not need a workshop, and nothing in it is hard on its own. Hex keys, a screwdriver, side cutters, wire strippers and a multimeter cover most of it, plus a soldering iron or a heat-set insert press for the brass inserts. Making your own leads also needs a crimp tool, or you can order the harness ready made. Every page lists the tools its own steps need.

It is a long build. The parts count runs into the thousands and the printing runs into months, so read this page before you buy filament. The point is not to put you off. It is so you plan for the right size of job.

You choose how tall the machine is

The machine is a stack of layers. Each layer holds 18 sorting bins, or 12 larger ones. More layers means more bins, so more different parts the machine can sort in one pass, a taller tower, and more of everything to build.

Bin size is a separate choice for each layer, and a machine can mix the two. You make it by choosing which funnel to print for that layer, so take it before you print: Funnel brackets compares the two and is where the choice is made.

Everything above and below the stack is the same whatever height you pick: one feeder, one top interface, one chute, one set of electronics. That is why the first layer costs far more work than the fifth.

Three and five layers are the two common choices.

A 5 layer machine stands 1270 mm (4 ft 2 in) from the floor to the top plate, and 1772 mm (5 ft 10 in) to the top of the bulk bucket sitting above it. A 3 layer machine is 950 mm (3 ft 1 in) and 1452 mm (4 ft 9 in). Each layer is 160 mm (6.3 in) of that. Measure your space before you choose a height: the bulk bucket is the highest point of the machine and it is where you pour the LEGO in, so you have to be able to reach into it.

What each size costs you

The table below is for 18 bin layers throughout.

	3 layers	5 layers
Sorting bins	54	90
3D printed parts	393	525
Different printed designs	99	99
Filament	15.5 kg	20.1 kg
Printing, one printer	537 h	713 h
Screws	666	886
Heat inserts	176	244
T-nuts	140	188
Other hardware	359	479
Electrical parts	149	157
Aluminium pieces	81	117
Laser cut parts	3	3
Parts in total	1651	2167

Bins are not in those totals. They are optional and you print them last: a 3 layer tower takes 54 printed bins (6.4 kg, 182 h) and a 5 layer tower takes 90 (10.7 kg, 304 h). You can also cut them from cardboard, or use boxes you already own. See Install the bins.

Two layers cost you about 130 more printed parts and 200 more screws. The tower is the cheap part. The machine around it is the work.

Every number above comes from the parts calculator. Set your own layer count and each layer's bin size there, and it lists exactly what to buy and print.

The room the machine will stand in

Pick that room now, before you buy filament, because it decides two things. This is where the finished machine runs, not where you build it: indoors, out of direct sun, in a room you would be comfortable working in.

How hot it gets decides your filament. Print the parts in PETG or ASA unless the room is air conditioned. PLA softens from around 55 C (131 F) and the printed gears the steppers drive through go first, which puts a PLA machine at about 40 C (104 F) against 45 to 50 C (113 to 122 F) in PETG. Nobody has tested a limit, so treat both as working figures. The Orange Pi is separate from the plastic: it throttles and then shuts down at about 105 C (221 F), see Orange Pi 5.

How damp it gets decides when you can switch on. In a humid climate, or a room that cools down overnight, do not switch the machine on while any part of it feels cold to the touch or looks wet. Let it reach room temperature first. The power supply needs 20 to 90% humidity with no water forming on it.

What the print figures mean

The filament and time figures come from the catalog, sliced on Bambu Lab A1 0.4 nozzle, profile 0.20mm Standard @BBL A1, in Bambu PLA Matte @BBL A1 at 15% infill. Your own printer and profile will differ. If the room means PETG or ASA instead, expect the weight and the print time to change with it.

Treat the hours as a floor, not a plan. They assume each part printed on its own plate, back to back, with nobody waiting. A real build runs about twice as long, and the extra is not the printer. It is the hours the printer stands finished because nobody is there to change the plate.

A 5 layer set of parts has been printed on one Bambu A1 in about three months, running five days a week including overnight, in PETG. Almost all the lost time was waiting for a plate change.

So, if you are planning:

• Start printing early. Print while you are still sourcing the rest.
• Fill the plate. Printing several small parts together is what turns the theoretical hours into real ones.
• Print in the order you build. The Assembly sections are in build order, so you can start assembling long before the last part is printed.

Which printer you need, how to place a part on the plate and what to check before a long print are on Printing the parts. The parts are designed to a 256 x 256 mm bed, and a smaller one cannot print all of them.

Two things you may not be able to make yourself

• Aluminium extrusion. A 5 layer machine needs 26 m of 2020 extrusion, cut into 117 pieces in 7 different lengths. If you have no saw, order it cut to length: many extrusion suppliers cut to order for a small fee per cut. The framing cut list has every length and a plan for packing them into standard bars.
• The laser cut parts. The top plate and the two cable cage plates are cut from flat sheet. Laser cut parts has the DXF for each one, to send to a local maker space or an online cutting service. Cardboard bins need a laser too, and their patterns come out of the bin generator.

Keep track of what you have

Parts arrive over several weeks, in the thousands. It is easy to lose track of what you already have. Label the screw sizes as they arrive, and keep the printed parts sorted by the assembly they belong to. Every assembly page lists the exact parts and fasteners for that step, so sorting them that way pays for itself.

Where to go next

• Printing the parts: what printer the parts need, orientation, supports, and the slicer checks worth doing before a long print.
• Assembly: the build order, structured like a set of instructions. Electronics is one of its steps.
• Electronics: the wire harness and the stepper pinout, installing the electronics, and connecting the components.
• Software setup: the last step of the build, where the finished machine hands off to installing the software and the SorterOS section.
• Parts: reference pages for individual parts, like the Lazy Susan bearing, and ordering the wire harness.
• Bill of materials: every part, with sources and part numbers.