Print-in-place bracelet: articulated, nothing to assemble

What it's for

• Bracelet to sell at a craft fair or market stall, changing only the two colors
• Desk fidget: in strip form the chain stays open, the kind you keep turning in your hand
• Color-coded wristband to tell groups apart at summer camp or day camp
• Calibration test for your printer: a 3-link strip tells you whether the machine resolves 0.3 mm of air
• Necklace or anklet, pushing the link count up to 40
• Decorative chain to hang: on a backpack, a Christmas tree, a rear-view mirror

What you adjust

• Shape: bracelet (ring), which closes the loop, or chain (strip), open at both ends
• From 3 to 40 links. On the ring the control won't go below 16: under that each joint bends too far and the ball escapes the socket, the cavity that wraps around it — it stops and says so, instead of generating a bracelet that falls apart
• Link size from 3 to 8 mm, in 0.5 steps — it drives the pitch, meaning how far the chain advances per link: at the default 0.30 mm clearance, a 3 mm link advances 10.3 mm; a 5 mm link, 15.1 mm
• Loop length is links × pitch: at that same clearance, 18 links of 3 mm close at 18.5 cm, an adult wrist. Asking for more clearance fattens the pitch — at the 0.50 mm maximum those same 18 links reach 19.2 cm
• Joint clearance from 0.20 to 0.50 mm, in 0.05 steps, 0.30 by default. The control won't go under 0.20 because below that no FDM printer resolves the air between two parts
• Each link is its own part with its own color: even links in one, odd links in the other, and you can change any of them

How to print it

• You get an STL with every link already in position — the slicer prints the whole chain at once, articulated. For the two-tone look, the 3MF comes out with each link on its own filament, in the version of the file your slicer reads (Bambu/Orca or PrusaSlicer)
• No supports. Support goes inside the socket, which is exactly where the ball needs to turn
• Each link is a sphere lying down: it touches the bed on a small spot. A brim helps — the shallow one-layer collar laid around the link's skirt to widen its grip on the bed. It's worth watching the first layer before walking away
• With an AMS, the slots panel orders the filaments to match your machine's physical layout before you export

Frequently asked questions

Does it really come off the printer articulated, with nothing to assemble?

Yes. Each link is a separate part in the file and it leaves the bed that way: none of them touches its neighbor, what holds them together is the shape. No pin, no glue and no clasp either — in ring form the loop already comes out closed.

How many links to fit my wrist?

Multiply links by pitch, which is how far the chain advances per link. At the default 0.30 mm clearance, a 3 mm link advances 10.3 mm: 17 links give 17.4 cm and 18 links, 18.5 cm. In bracelet shape the minimum is 16 links.

What if the links come out fused?

That's the risk of any print-in-place, and it depends on your printer: over-extrusion — when the machine pushes out too much filament — closes a 0.3 mm gap and welds the chain shut. Before spending an hour on a 20-link bracelet, print a 3-link strip: it takes minutes and answers the question.