Nylon filament: choosing PA for functional and moving parts
Nylon becomes interesting when a printed part moves repeatedly, runs against another surface or needs to deform during assembly. The name covers a family of polyamides, however. PA6, PA11, PA12 and blends have different requirements and properties. A generic “nylon profile” is therefore an unreliable starting point for every spool.
Three things need to work together: the particular material, a suitable printing process and a design that performs in service. Moisture management is especially important. Dry filament helps during printing, while the finished part can still change as it absorbs moisture later.[1, 2]
When is nylon a useful choice?
Possible applications include guides, spacers, sleeves and moving connections where friction and repeated deformation matter. The appropriate grade depends on contact conditions, load and environment. Nylon does not automatically produce a finished bearing or replace every engineered plastic bush.[1]
| Application | What to evaluate |
|---|---|
| Removable sleeve or cap | Insertion force and fit after moisture uptake |
| Sliding contact | Mating material, surface finish, contamination and actual wear |
| Repeatedly flexed clip | Flexing region, notches and layer orientation |
| Bolted bracket | Contact areas and possible deformation under sustained clamping |
| Dimensionally important connector | Measurements under service conditions as well as immediately after printing |
If the first question is simply whether dimensions or a movement feel right, an initial PLA or PETG prototype may get you there faster. Establish the final fit again with the intended nylon and its process.
Distinguish PA6, PA11, PA12 and filled variants
A material name starts the selection process; it does not replace the data sheet. Typical PA12 formulations absorb less moisture than PA6, but that does not create a universal ranking for strength or printability. Copolymers and additives can change behavior further.[3]
| Material label | What to establish before choosing it |
|---|---|
| PA6 | Moisture state, dimensional changes and the particular product's requirements |
| PA11 | Chamber, build surface and manufacturer profile; PA11 is not automatically easy to print |
| PA12 | Properties in dry and conditioned states, plus available profiles |
| Copolyamide, such as PA6/66 | Its own formulation and process instead of a generic PA6 profile |
| PA-CF or PA-GF | Base polyamide, fiber reinforcement, nozzle requirements and directional mechanical behavior |
Carbon or glass fibers create a different material variant. Do not carry over your experience with an unfilled nylon unchanged to PA-CF. In particular, establish whether the part should resist bending or bend repeatedly. A higher stiffness value does not answer the second question.
Printing settings: two products with very different requirements
The comparison below deliberately shows specific manufacturer examples. It is not a shared settings table for all nylons. Values from these different products must not be combined into a new universal profile.[4, 5]
| Setting | Polymaker PolyMide CoPA | Prusament PA11, unfilled |
|---|---|---|
| Nozzle temperature | 250–270 °C | 275 ± 10 °C |
| Bed temperature | 25–50 °C | 100 ± 10 °C |
| Chamber | Follow the product and printer profile | 55 ± 5 °C according to the manufacturer |
| Drying | 100 °C for 8 hours | 90 °C for 6–8 hours |
The printer must support these conditions within its approved operating limits. A sufficiently high nozzle temperature is only one requirement. Build surface, thermal control, filament path and drying also need to match the material.
Nozzle material is another product-specific decision: Prusa describes its unfilled PA11 for a standard 0.4 mm brass nozzle, while Polymaker recommends a wear-resistant nozzle for CoPA. Check the manufacturer's requirement even when the spool does not say “CF.”[4, 5]
Dry the filament and keep it dry during printing
If moisture is present during extrusion, changing retraction or flow alone will not reliably fix the resulting print defects. Start by checking the spool's condition. Filament kept in dry storage is not automatically equivalent to filament dried according to its manufacturer's procedure.
A useful sequence for your trial is:
- Record the product, batch and manufacturer profile.
- Dry it when needed using its own procedure. Both dryer and spool must tolerate the specified temperature.
- Protect the prepared filament from renewed moisture uptake.
- For a long print, provide a suitable dry feed arrangement when the product requires it.
- Compare other settings only after material preparation is reproducible.
Desiccant helps with storage; it is not a universal substitute for active drying. Avoid choosing a higher temperature simply to save time. See filament drying and filament storage for preparation details.
Dry filament and a conditioned part are different subjects
Conditioning concerns the moisture state of the finished part. As a polyamide absorbs water, it can become less stiff and more deformable; dimensions can change too. The extent and rate depend on the material and environment.[2]
For a fit, this means a pin that fits immediately after printing does not establish how assembly will work later. Define the conditions in which the part will be used and evaluated. Record storage duration and environment when comparing samples instead of treating dry and differently stored parts as equivalent specimens.
Annealing is also different from drying or moisture conditioning. A specified heat treatment can affect geometry and material state. If the manufacturer requires it for the intended property, carry it out before final dimensional checks. Do not borrow a procedure from another polyamide.
Example: a removable cap for a profile
Suppose a cap needs to fit a profile and be removed regularly for cleaning. Start with the end-cap generator to represent the measured connection geometry. The following steps concern design and print evaluation; they do not assume extra generator features.
Begin with a short test section containing the connection and insertion depth. Check it on the real profile. Small differences caused by coatings, edges or a seam are easier to identify on the mating part than from nominal dimensions alone.
Next, compare a few versions with deliberate changes to clearance. Keep external and other functionally important dimensions unchanged. Global scaling changes everything at once and makes the results harder to interpret.
Evaluate more than whether the cap can be installed. It should also come off without unwanted levering and retain an appropriate fit after several assembly cycles. Repeat the trial after storage representative of the intended use. Record material, orientation and measured connection dimensions alongside the result.
This is a manageable evaluation for a cap. For a load-bearing connection, such prototypes do not replace adequate engineering and validation. The fits and tolerances guides provide further design context.
Narrow down common problems
| Observation | Useful next check |
|---|---|
| Popping, bubbles or unusually rough extrusion | Check material condition and drying before changing other variables |
| Edges lift from the build plate | Review surface suitability, first layer and product-specific thermal conditions |
| Dimensions change after storage | Compare moisture state and measurement conditions |
| A connection fits initially and differently later | Repeat under service conditions and evaluate local fit dimensions |
| A clip breaks instead of bending | Review grade, reinforcement, notches, bend radius and print orientation together |
| Results differ with the same profile | Record preparation, batch and environmental conditions |
One observation can have several causes. Change one factor per comparison where practical so you can identify its effect.
Related generators
Frequently asked questions
Is nylon always stronger than PETG?
No. “Stronger” can mean stiffness, breaking load, impact behavior or performance under sustained load. Compare the property your part actually needs under similar test conditions. Print orientation and design still matter.
Can I print nylon on an open printer?
That depends on the product. The examples above already differ substantially. Choose an approved profile for your machine and consider part size and environment. An enclosure must not take the printer beyond its permitted operating conditions.
Does every nylon need drying before every print?
An inflexible timetable says little. Starting condition, product requirements, storage and print duration matter. Plan material preparation to be reproducible.
Is PA-CF the best choice for flexible clips?
The abbreviation cannot establish that. Check the particular formulation's deformation behavior and the geometry. A material that stiffens a bracket may be unsuitable for a repeatedly flexed clip.
Can I replace a maintenance-free bearing with a print?
Treat a printed guide as an evaluation project. Mating surface, clearance, speed, load, temperature and contamination determine suitability. Low material friction alone does not establish service life.
Why does my part fit differently a few days later?
Moisture uptake is one possible cause; temperature, measurement method or mechanical deformation can also matter. Compare documented conditions and measure the same locations. Do not immediately enlarge the whole model.
Next step: Configure an end cap and evaluate its connection with a short fit sample under the intended service conditions.