Design guide
Design parts that print right first time.
Honest, opinionated rules for FDM, written by the engineers who actually have to press “print” on your file. No theoretical minimums, just numbers that work on our Bambu machines week in, week out.
Get an instant quoteWall thickness
How thin you can go before parts get fragile, translucent, or fail to print at all.
ReadOverhangs & supports
Print angles you can get away with, when supports are mandatory, and how to design them out.
ReadTolerances & fits
Real-world tolerance numbers for FDM, plus clearances for press / running / loose fits.
ReadOrientation & strength
Layer direction is the single biggest factor in part strength, here's how to use it.
ReadHoles, bosses & threads
Hole shrinkage, captive nuts, heat-set inserts, and when to print a thread vs tap one.
ReadFile prep & export
Export settings that won't bite you, Fusion 360, SolidWorks, Onshape, Blender.
ReadWhat is FDM?
FDM, Fused Deposition Modelling, is the most common form of 3D printing. A heated nozzle traces your part one layer at a time, melting a thermoplastic filament onto the layer below until the part is complete. Bambu A1 and P1S printers, the machines we run, do this very accurately at 0.08-0.28 mm per layer.
It's the right process when you need a functional part fast, in a real engineering plastic (PLA, PETG, ABS, ASA, nylon, TPU), without the cost of injection moulding. It's not the right process when you need optical-clear parts, micron-level surface finish, or features below ~0.4 mm, for those, look at SLA or CNC.
The rules in this guide are about making the most of what FDM is good at: strong, geometrically faithful, repeatable parts at a price you can stomach for one-offs.
Skip the guesswork.
Upload your part, we'll flag anything that won't print and suggest a fix before any charge.
Get an instant quoteLast reviewed May 2026 · Rigid Prints engineering team