Hardened Nozzles: Ruby, Tungsten, and Steel Compared

Harry S.

When Brass Isn't Enough

Standard brass nozzles are excellent for the vast majority of FDM printing: PLA, PETG, ABS, TPU, and ASA are all non-abrasive and cause negligible brass wear. But introduce chopped carbon fibre, glass fibre, metal powder, or strontium aluminate (glow in the dark particles) into the filament, and brass wears out rapidly. The nozzle orifice enlarges, print quality degrades, and eventually the nozzle needs replacement. Wear resistant nozzle materials were developed specifically for this problem.

Understanding which nozzle material to use and when is a practical necessity for any maker who is keen to explore composite or speciality filaments. The excellent news: for most applications, hardened steel is all you need, and it's only modestly more expensive than brass.

Hardened Steel: The Standard Upgrade

Hardened steel nozzles are the go to recommendation for abrasive filament printing. They're much more wear resistant than brass, hardened to HRC 55–65 depending on the alloy, and can handle hundreds or thousands of hours of carbon fibre, glass fibre, and metal fill printing without measurable orifice enlargement. The trade-off: hardened steel has lower thermal conductivity than brass (roughly 3× lower). At equivalent settings, this difference means the plastic at the nozzle tip is slightly cooler, which can reduce maximum flow rate by 10–15% compared to brass. At low to moderate speeds, this difference is inconsequential. At high speed, high flow rate printing, it may require a slight temperature increase to compensate.

Hardened steel is available in E3D, Bondtech, and compatible formats from most hotend suppliers. The price premium over brass is typically $8–20 per nozzle, a worthwhile investment for any abrasive filament use. Use hardened steel for all carbon fibre composites, glass fibre filled filaments, metal fill (iron, copper, bronze), glow in the dark, wood PLA, and any other filled or composite speciality material.

Ruby-Tipped Nozzles: The Premium Option

Ruby-tipped nozzles (Olsson Ruby, Bondtech CHT Ruby) use a synthetic ruby gemstone as the nozzle tip. Ruby has a Mohs hardness of 9, harder than virtually any material you'll encounter in FDM printing. A ruby-tipped nozzle is essentially wear proof for all practical purposes; some operators have run thousands of hours of continuous carbon fibre printing through a single ruby nozzle without detectable wear. The thermal conductivity is also excellent, better than hardened steel, allowing high flow rates without temperature penalties.

The significant premium ($80–150+ per nozzle) limits their appeal to dedicated setups. If you have a machine specifically configured for PA-CF or PETG-CF production, a ruby nozzle is a worthwhile lifetime investment for that machine. For a machine that occasionally prints abrasive materials alongside standard filaments, hardened steel is the more economical choice. See our engineering materials guide for the complete setup context of abrasive material printing.