How to Print Nylon Successfully: PA12 and PA6-CF
Dry PA12 at 80°C for 8 hours and PA6-CF for 12 hours before printing — including freshly opened spools. Use an enclosed printer, disable cooling, and print on a bed treated with PEI or glue stick. Wet Nylon and printing without enclosure are the two causes of almost every Nylon print failure.
Nylon is a transformative material for functional 3D printing. PA12 provides toughness and flexibility that no other common FDM material approaches. PA6-CF provides stiffness approaching aluminium at a fraction of the weight. Getting consistent results requires attention to three things: moisture, temperature, and bed adhesion. Everything else is secondary.
The Moisture Problem
Nylon is extremely hygroscopic. PA6 absorbs moisture faster than virtually any other common FDM material. Even a few hours of open-air exposure in a humid environment is enough to produce visible stringing, surface bubbling, and weakened layer adhesion.
Symptoms of wet Nylon:
- Popping or crackling from the hotend
- Excessive stringing, far more than usual
- Rough, bubbly, or foamy surface texture
- Poor interlayer adhesion — parts that peel apart easily
- Dimensional inconsistency
The fix is always drying first. Dry PA12 at 80°C for 8 hours. Dry PA6-CF at 80°C for 12 hours. This applies to freshly opened factory-sealed spools too — vacuum sealing stops further absorption but does not remove moisture already present in the filament. If you have been printing with fresh filament from an open spool for more than a few hours, the quality will have degraded — dry it.
Enclosure Requirements
Nylon warps. Not as badly as pure ABS, but significantly enough that large prints without an enclosure will frequently fail through corner lifting or layer separation mid-print.
An enclosed chamber maintains the ambient temperature around the print, slowing the cooling rate of each deposited layer. The result is dramatically reduced warping and better layer adhesion throughout the print height.
If your printer does not have an enclosure, you can improvise one — a cardboard box placed over the printer during printing is surprisingly effective for smaller prints.
Print Settings Summary
| Parameter | PA12 | PA6-CF |
|---|---|---|
| Nozzle temperature | 245–260°C | 255–270°C |
| Bed temperature | 80°C | 85°C |
| Cooling fan | Off or 10% max | Off |
| Print speed | 45–55mm/s | 40–50mm/s |
| Enclosure | Recommended | Recommended |
| Nozzle type | Brass OK | Hardened steel required |
Bed Adhesion
Nylon adhesion to cold glass is poor. PEI sheets work well for Nylon when cleaned with IPA and lightly coated with a PVA glue stick. The glue stick serves two purposes: it improves initial adhesion and acts as a release agent when the print cools, preventing the Nylon from bonding so strongly that removing the print damages the sheet.
Layer Adhesion in Nylon
Unlike PLA and PETG which bond through mechanical interlocking and some surface fusion, Nylon bonds strongly through actual polymer interdiffusion between layers. This is why Nylon parts printed correctly have exceptional Z-axis strength — the layers genuinely fuse.
Cooling fan speeds above 20–30% interrupt this bonding by cooling the deposited layer too quickly before the next layer arrives. Keep cooling off or minimal for all Nylon materials.
Related materials
Download PDF reference
Print-ready A4 landscape summary — keep it at the printer for quick reference.
Download PDFNeed help with your project?
Get in touch for a consultation, print quote, or just to talk through material selection.