Filament diameter: 1.75 or 2.85 mm

Two standards

The thicker 2.85 mm filament was used mainly with older printers with Bowden feeding. Today the vast majority of brands and printers use 1.75 mm. It is more flexible, cheaper and can be metered more finely, so new machines work with it too. Wikipedia on FFF technology has basic information about the materials.

The diameter has nothing to do with the diameter of the nozzle. The nozzle is usually 0.4 mm, and 1.75 mm filament is melted in it and pushed through the narrow opening.

Why tolerance matters

Even good filament is only approximately what is claimed. Manufacturers state a tolerance, for example ±0.02 mm. When the strand is thinner in places, the nozzle gets less plastic than the printer expects and gaps appear, which is called under-extrusion. When it is thicker, you get over-extrusion and a rough surface.

Our price is worked out from the real grams from print preparation, so we do not need any diameter data from you. A stable diameter is our concern, not yours.

What this means for an order

You choose nothing. We print on Elegoo Centauri Carbon 2 printers, which use standard 1.75 mm filament, and you only choose between PLA and PETG. You do not need to think about it when modelling, as the filament diameter does not affect the dimensions of the part.

We do not sell filament. If you print at home, first check in your printer's manual which diameter it needs.

Can the diameter vary along one spool

It can, and small deviations are common, especially with cheap brands. It helps to measure it with calipers in several places along the strand and enter the diameter in the slicer. Usually, though, it is enough to buy a proven brand and not skimp on the material your parts are made from.

When diameter matters at home

If you print at home, the filament diameter is entered in the slicer program and affects the flow. When the real diameter is 0.05 mm higher than the one entered, the printer extrudes several percent more plastic than it expects, and the surface is rough. So it is enough to measure the filament once with calipers and adjust the value if the difference is obvious.

Filament of a different diameter than 1.75 mm will not fit an ordinary printer, so when buying always check what your printer supports.