Most of the revisions we do aren't because a part is hard to design. They're because a file was drawn for injection moulding, or for a render, and the geometry assumes a process that doesn't apply. A part that prints cleanly the first time is almost always a part that was *designed* for printing.
The file formats that actually help
Send us a STEP file if you have one, not an STL. STEP carries real geometry — curves, cylinders, dimensions — which we can edit, offset and measure properly. An STL is a triangle mesh: fine for printing as-is, useless if we need to tweak a wall thickness or add a clearance.
If all you have is a sketch or a physical sample, don't worry — that's what 3D scanning and reverse engineering are for.
SHIPS 3–5 DAYS
Wall thickness
The single biggest source of failed first prints is a wall that's too thin to exist. As a rule of thumb, keep load-bearing walls at 2 mm or more, and non-structural walls at 1.2–1.5 mm. If a feature is thinner than the printer's nozzle width it simply won't print — it disappears in the slicer or comes out as a wisp.
Thick is safe, but thick is also slow and heavy. The skill is putting thickness where the load is and letting the rest stay light. If you're unsure, oversize and let us thin it back.
Overhangs and support
FDM builds upward, so any surface steeper than roughly 45° from vertical needs support, and support leaves a finish mark. You can't always avoid it, but you can hide it: put the rough side where it won't be seen, or design a 45° chamfer where the eye expects a fillet.
Bridging — a short, flat span between two points — prints surprisingly well and often needs no support at all. A long unsupported shelf, less so.
Clearances matter more than you think
A press fit in CAD is not a press fit in plastic. Printed parts have real tolerances — layers, shrinkage and nozzle width all add up. If two parts are meant to mate, build in a clearance from the start: 0.2–0.3 mm for a snug fit, more for a part that has to slide or clip repeatedly.
What we check on every file
Before anything prints, we run the model through the same review as our own work: wall thickness at the thinnest feature, overhangs against the chosen material, and the critical dimensions flagged for verification. That review is why a custom part can go from your file to a testable print without a surprise.
Not sure whether your file is printable? Send it over and we'll tell you what we'd change before you commit to a print.
