PA-GF

PA-GF is polyamide (nylon, usually PA6 or PA12) reinforced with chopped glass fiber, typically 20–30%. The glass fiber sharply increases stiffness and dimensional stability, while the nylon matrix delivers wear resistance and performance under heat. It is an engineering filament: it carries mechanical load and tolerates temperature far better than PLA, PETG or ABS, but it demands a properly equipped printer and mandatory drying.

What it's good for

• Gears, rollers, guides and other wear parts that run under friction.
• Load-bearing brackets, mounts and structural parts where high stiffness matters.
• Production tooling: jigs, fixtures and grippers for assembly.
• Drone, RC and robot parts — light yet strong and impact-tolerant.
• Components that get warm in service (near motors, under the hood) where PLA and PETG soften.

Where not to use it

• Decorative models and simple household trinkets — too costly and fiddly; PLA or PETG is the easier choice.
• Tight-tolerance dimensional parts without a dialed-in process: nylon shrinks and warps, so holding tolerances is hard.
• Items needing a smooth cosmetic surface — glass fiber leaves a matte, gritty finish.
• Unprotected parts that sit in damp environments for long periods: nylon absorbs moisture and its properties drift over time.

How to print

• Nozzle temperature: 260–290 °C. An all-metal hotend is required — a PTFE liner breaks down at these temperatures.
• Bed: 50–90 °C (some grades run 100–110 °C on PEI). On glass or smooth PEI a glue stick or dedicated adhesive is mandatory.
• Enclosure: a closed enclosure is strongly recommended — it keeps a warm chamber around the part and cuts warping and delamination.
• Part cooling: minimal, 0–40%. Heavy cooling weakens nylon's layer bonding.
• Speed: moderate, usually up to 100–130 mm/s — with glass fiber, rushing hurts quality and wears the nozzle faster.
• Adhesion: a wide brim, a clean bed and glue. A raft helps on large parts.
• Retraction: tune by trial — nylon tends to string; with dry filament a moderate retraction usually beats a large one.
• Nozzle: hardened (steel) only — glass fiber quickly grinds down brass.

Drying and storage

Nylon is critically hygroscopic — it eagerly absorbs moisture straight from the air. Printing wet filament causes bubbles, hissing and steam at the nozzle, a rough surface, and a weak, brittle part. For PA-GF, drying before printing is not optional but mandatory, and printing straight from a heated dry box is best.

• Drying: 70–90 °C for 8–12 h (around 80 °C is ideal). Do not exceed 100 °C — the spool can deform.
• Storage: an airtight container or vacuum bag with desiccant; printing from a heated dry box is best.
• Signs of moisture: hissing and steam at the nozzle, tiny bubbles, a fuzzy surface, brittleness and weak layers.

Pros and cons

• Very high stiffness and dimensional rigidity thanks to the glass fiber.
• Excellent wear resistance — great for friction parts, gears and bushings.
• High heat resistance: the part holds shape where PLA and PETG already soften.
• Good impact and fatigue resistance, plus the nylon matrix's chemical resistance.

• Critically hygroscopic: without drying and dry storage you won't get a sound part.
• Abrasive: a hardened nozzle is mandatory and the nozzle still wears.
• Demanding on hardware: an all-metal hotend and an enclosure are effectively required.
• Prone to shrinkage and warping — needs glue, a brim and careful bed adhesion.
• Gritty, matte surface — not a material for cosmetic models.