Spaghetti in 3D printing: why it happens and how to avoid it

How spaghetti forms

In FDM printing a model is built up in layers. If a layer does not hold on the previous one, for example because the part came off the plate or a tall thin tower snapped off, the printer does not know. It carries on following the original plan and pushes plastic out into empty space.

The plastic hangs there and tangles into a mess that looks like cooked spaghetti, hence the name. The mess can catch on the nozzle and spoil the rest of the print too.

The most common causes

• Poor adhesion to the plate. A part with a small contact area or a tall narrow body comes off and tips over during printing.
• Insufficient supports. An overhang with nothing under it has nothing to stand on, and the plastic falls down.
• Damp filament or a clogged nozzle. The print breaks off for a moment and the following layers have nothing to rest on.
• Model shape. Thin slender parts wobble when the nozzle touches them and can knock the whole part loose.

What you can influence in the design

Spaghetti can be avoided mainly through shape. Give the part the largest possible flat area on the plate, avoid very tall thin towers and have overhangs above roughly 45 degrees supported. You will find more on this under overhangs and model orientation.

It also helps to turn the part so that it lies on its widest side. That is usually the safest for printing, and the part is stronger too, because the layers do not run through the thinnest spot.

How we deal with it

After you upload a model we really do prepare it for printing on our server, so the slicer adds supports itself wherever the model needs them, and their cost is in the price per part. We print on enclosed printers and photograph every batch before dispatch.

No print can rule out failure completely. If your shape is risky, for example very tall and thin, write to us at jakub.novak@boostello.com and we will advise how to adjust it.