Most failed prints we've had to redo came down to five simple things. None of them need 3D modelling experience to fix — just a few minutes in your slicing software.
· 6 min read
We're a print bureau, not a modelling service. We take the STL or 3MF file you give us and print it. That means the quality of what comes out of the printer is heavily influenced by how that file was prepared — and almost every problem we've had to reprint was caused by something that could have been caught before the file was sent.
None of this is a criticism of your modelling. It's just how slicing works, and it's genuinely fixable.
Thin walls snap, curl and lift off the bed. The general rule for FDM printing is three perimeters minimum, and for anything functional, four to six. If your model has single-wall sections, they'll usually fail.
The fix is simple: in your slicer, add more perimeters. If the model is a solid part, you can also just enable a "solid" or "infill 100%" option and skip the problem entirely.
This is the most common one, and it comes from models downloaded in millimetres when the printer works in inches (or vice versa). A 100mm model can easily end up printing at 254mm, or 39mm.
How to check: look at the dimensions in your slicer's preview before you send the file. If a car model is showing up as 2cm long, it's scaled wrong. Slicers usually have an "auto-fit to build plate" option, but be careful — that one will happily stretch a model to fill the bed, which is worse.
The fix: in the slicer, scale the model to the size you actually want, then confirm the printed height in the preview matches. If you're not sure what size you want, measure something you already own and work from that.
Anything that extends horizontally into thin air at an angle steeper than roughly 45–50° will droop or collapse. Common culprits: roof overhangs, a person's arms out to the side, the underside of a shelf, a laptop lid, a chin on a figurine.
The fix: turn on supports for the print, or orient the model so the overhangs become something else. Enabling supports is usually the quickest fix and the print cost difference is minimal — support material is mostly recyclable scrap.
The exception is a model with overhangs on a surface that must stay smooth. In that case, rotating the model is worth the effort.
Text is one of the most common reasons we get asked to reprint. If the text was added as a separate object in the modelling software, it might be floating, intersecting, or set at the wrong height. Slicers will often treat it as a second object with its own base — so it can end up offset, mirrored, or printed separately.
To check this, slice the file and look at the layers in the preview. If you can see the text sitting proud of, or floating above, the model, it needs to be merged and aligned properly.
The fix: in the modelling software, ensure the text is converted to a mesh and booleaned/merged into the body of the model so it's a single watertight object. If you don't have a modelling tool, we're happy to look at the file and tell you whether it needs work before you commit to a print.
We need STL or 3MF. Other formats cause problems: OBJ doesn't reliably carry scale, STEP and IGES are CAD formats that don't translate cleanly, and a screenshot or a PDF obviously won't print.
3MF is the better choice where available because it stores the actual colour and units, and it keeps the file watertight when saved. STL is the safer, more universal option and works for almost everything.
If you're exporting from your slicer, .3mf or .gcode are both fine — a sliced file means the print is already set up and we can run it exactly as you've previewed it.
Our file preparation guide covers the full process step by step. And if you send us a file, we'll tell you if there's a problem with it before you commit to anything — no charge for a look, and we'll tell you plainly if it's fine as-is.