Joining printed parts with adhesive (cyanoacrylate, epoxy, UV resin) when mechanical joints alone are insufficient for the required strength.
Adhesive bonds fill voids between printed surfaces and cure to a continuous film. Bond strength depends on bond-line thickness (optimum 0.05–0.2 mm), surface roughness (FDM ridges increase effective area), and adhesive compatibility with the polymer. Cyanoacrylate bonds PLA/PETG well; epoxy fills gaps in rough SLS surfaces; UV resin reinforces SLA joints post-cure.
Design a 0.1–0.2 mm lap gap between bonding surfaces. PLA: medium-viscosity CA glue with accelerator. PETG: epoxy; CA may stress-crack PETG. SLS PA12: sand lightly, structural epoxy, cure under pressure. ABS: acetone welding is effective for internal bonds.
CA glue on standard SLA resin causes brittle cracking under peel loads: use epoxy. Over-applying adhesive creates a weak, porous layer. Avoid bonding load-bearing Z-axis seams: bond XY-plane split lines instead. Never bond parts expected to be disassembled.
Related terms: Press-fit joint, Heat-set threaded insert, Joint orientation for load direction
| Theme | assembly |
|---|---|
| Also called | glued joint, epoxy joint, superglue assembly |
| Source | sources/2026-04/2026-04-24--3d-printing-best-practices-guide |
Engineer, author of The Big Book of 3D Printing and additive manufacturing expert