Snap-fit connector generator for printed parts
A snap-fit joint is a connection that clicks together without glue or screws, held by the plastic's own springiness. These joints are built from calculation, not guesswork: for every seam between printed parts the engine places the right type of connector, with clearance tuned to FDM shrinkage, and checks the part can survive it. You upload a model — you get parts that fit.
How the engine builds a joint
A joint is built with a boolean operation: the male half (a peg or pin) is added to one part, and its negative plus clearance is subtracted from the other to form the female socket. The connector type is chosen to match the seam, and its dimensions are computed for the material and load rather than stamped from one template.
- Upload a model or an assembly of parts in the browser.
- Mark where the seams run — or cut the model right here, by color or by size.
- The engine picks a joint type per seam and computes clearance for the chosen plastic.
- Download the 3MF: each part already carries its peg or socket, ready to print and snap.
Connectors the generator produces
- Tenon (peg-and-socket) — the general-purpose joint for flat and volumetric seams; works in alignment and shear.
- Pin — a thin guide finger for when there is little material and a full peg will not fit.
- Dovetail — holds in shear along the seam and only separates along the slot.
- Cantilever clip — a releasable joint that actually clicks on assembly.
- Magnet — when the wall is too thin for a peg, the engine adds a magnet pocket so it will not punch through the part.
The clearances and margins built in
A joint holds on verified numbers — verified numbers, not vague advice:
- Clearance: a snug 0.30 mm per-side fit by default, plus loose 0.45 mm and tight 0.18 mm; on top comes material shrinkage compensation (PLA 0.3%, PETG 0.5%, ABS 0.7%).
- Walls around the joint: at least 1.5 mm of wall behind a socket, and a 2.0 mm printable bridge of material between two adjacent joints.
- Cantilever clip: deflection is designed to ≤50% of the material's strain limit (a 2x margin), and the beam length-to-thickness ratio stays in the 5–10 range, or the beam is either brittle or floppy. Strain limits: PLA ~4%, ABS ~6%, PETG ~7%.
How each clip type is built is covered in the wiki on snap-fit joint types for FDM; how clearance is computed against shrinkage is in snap-fit clearance.