What does minimum nozzle size mean?
Short answer
The minimum nozzle size is the smallest nozzle the maker recommends for a filament. It usually appears on filled filaments, which contain particles such as carbon fibre, glass fibre, wood, metal or glow powder. Those particles can block a nozzle that's too small.
Guide
Which filaments need a larger nozzle?
- Carbon and glass fibre filaments often need at least 0.4 mm, and many makers recommend 0.6 mm.
- Wood, metal and glow-in-the-dark filaments usually need 0.4 mm or larger.
- Plain PLA, PETG and ABS have no particles, so they work with small nozzles, down to 0.2 mm for fine detail.
Hardened nozzles
Many filled filaments are also abrasive: carbon fibre, glass fibre and glow powder wear away a standard brass nozzle quickly. Use a hardened steel or similar wear-resistant nozzle with them.
Minimum nozzle questions
Can I print carbon fibre filament with a 0.4 mm nozzle?
Often, yes, but check the minimum the maker lists. Many recommend 0.6 mm to reduce clogs, and you'll need a hardened nozzle either way.
Why does my filled filament keep clogging?
Usually the nozzle is too small for the particles, or it's worn. Try a larger hardened nozzle and make sure the filament is dry.
Do I need a hardened nozzle for glow-in-the-dark filament?
Yes. Glow powder is very abrasive and wears brass nozzles quickly.
What if no minimum nozzle is listed?
For plain filaments, any common nozzle size works. For filled filaments, assume 0.4 mm or larger unless the maker says otherwise.