PA6 (especially PA6-GF) is an awesome filament—super strong and probably one of the best for functional parts. However, it’s a pain to print and warps like crazy and all the tips I found on the internet for printing it weren’t succesful. I finally succeeded so here’s a quick tutorial.
The Problem
I spent considerable time trying to figure out warp-free PA6 printing. No matter what I tried, warping persisted:
Various chamber and bed temperatures
Different bed surfaces (Biqu Glacier, textured PEI, smooth PEI, Prinplate Extreme FR4)
Tried Bambu’s liquid glue
Extended drying at high temperatures
The Solution: PETG Interface Layer
After extensive testing, I found the perfect solution: print PA6 on a thin PETG interface layer instead of directly on the build plate.
Why it works:
When warm, PETG and polyamide bond exceptionally well (prevents warping)
When cooled, PETG peels off easily (like PLA/PETG combinations)
PETG adheres to the bed better than ABS/ASA alternatives
Lower bed temperature (70°C vs 100°C) reduces chamber/bed temperature differential which reduces warping further
How to make the Interface layer
Method 1: Bambu Studio (Complex)
Don’t use the raft function—it won’t give perfect results. Steps:
Copy your part in place and merge it
Add a cube larger than your model
Merge the cube with your original part and the copied part
Move only the cube 0.3mm up along the Z-axis
Use Mesh Boolean to subtract the cube from your copied part(creates 0.3mm slice)
Move original part 0.3mm up along Z-axis
Assign PA6 to original part, PETG to bottom slice
I might make a detailed tutorial for this method later.
Method 2: CAD (Recommended)
Create the interface layer as an extra solid in CAD (around 0.3mm thick depending on your layer height, for 0.2mm I would use a 0.2mm interface layer)
Save as STEP file
Import into Bambu Studio
Check “Split compounds and compsolid into multiple objects”
PETG:
Bed Temp: 70°C
Chamber: 0°C (doesn’t matter though get overriden with the 60°C from the PA6). The high bed temperature doesn’t affect the PETG at all, didn’t have any clogs so far).
Otherwise stock settings for PETG
Results
This method produces near perfect, warp-free prints even on especially warp-prone models. Tested successfully with:
Biqu Glacier bed surface
Stock PEI sheets
Should work with any PETG-compatible surface
Additional Notes
I think it should work without a heated chamber (untested)
Also works for ABS printing with PETG interface layer (no heated chamber needed)
Don’t know if that also works with PA12 but I don’t see a reason why not
If anyone knows of other filament combinations that work well, please share! I’ve attached a video at the end that explores filament combinations, particularly for ABS.
Here are the pictures, the PA6 could have been dryer though but still a very good result (PA6-GF in grey, PETG in Black)
There’s definitely something else going on. Don’t get me wrong, interface materials are definitely a solution that has been used before and works. And PA6 is not as easy to print as 11 or 12.
But I’ve printed PA6 for years and the biggest discriminant has been the material itself. Some blends are just awful, pure polymers in a filament form. Surfaces too, a good and clean FR4 works wonders (assuming it’s actually untreated FR4 and not some generic laminate).
Have you tried switching suppliers/going for name brands/proprietary blends?
Yeah depends on the type of PA. i.e. Sunlu’s easyPA prints wonderful without any interface layer.
I mainly use Bambus PA6-GF from different batches but always had a big warping problem. Additionally, other PA6-GF options are not really widely available here. Currently, your choices are limited to Sunlu PA6-GF (which I believe is produced in the same factory as Bambu’s PA6-GF) and Polymaker’s PA6-GF, the latter of which I found only in a 2kg or 0.5kg spool, making it incompatible with the AMS. Fortunately, these materials are easily accessible here in Europe, although they are not particularly inexpensive so throwing out a spool because it warps more than others is not really feasible.
I also see no drawbacks to using an interface layer. It doesn’t significantly increase print time, and the Z-axis tolerances remain largely unaffected.
Also tried this FR4 printplate but without success (and yes it was clean etc.)
Also tried this FR4 printplate but without success (and yes it was clean etc.)
That’s really thin (not that in an H2 you can get much thicker) and not real FR4, as in not the graded kind used in PCB production but the generic laminate. You would need at least 3mm for a plate to limit the vertical warping effect and avoid detachments. Cleaning does include an Acetone rinse as they do come with a protective oily film (or at least most PCB stock does). Additionally, a light wet sanding does wonders for warping prevention.
I’m in the EU too, I’ve used both STYX PA6-GF30 and Fiberon PA6-GF25 in an AMS, two spools at a time for continuity. The 500g size hasn’t been an issue (the cardboard spool is annoying for drying though). The engineering plate and glue works great too. Non-GF PA6 is dare I say easy to come by too?
I also see no drawbacks to using an interface layer. It doesn’t significantly increase print time, and the Z-axis tolerances remain largely unaffected.
I just think that not throwing out additional plastic when printing is neat.
i bought special nylon printing glue, and put down a brim, and that fixed my PAHT-CF warping problem. I need to print from a drybox as well, but that’s just where I live. Printer is H2D. Glue is unbranded AliExpress or I’d give the name,
Why does the thickness of the FR4 make such a significant difference? After all, the PA only contacts the surface of the FR4, so whether it’s 1mm or 3mm shouldn’t matter much. I can see how thickness would be important for a traditional bed before we had magnetic beds (only atttached with some brackets). However, with modern magnetic beds, I struggle to see how thickness impacts performance, but I’m open to learning more.
Additionally, I’ve wasted far more plastic on failed prints due to warping than I would ever lose with a 0.2mm interface layer of PETG. I appreciate that you have a setup that works for you. Personally, I’m tired of buying different plates and trying to make them work (I mean I bought 3 additional plates to the stock textured PEI). Since you can print at much lower bed temperatures and avoid purchasing a new bed, you end up saving more material in the long run.
Also Im gonna try out to print it without a heated chamber. That would be a game changer to be able to print in on an A1 i.e.
Before investing in specialized beds, I would recommend experimenting with some interface layers. If you primarily print with PA6, it might be worth investing in a dedicated bed sheet, but my own experience with that approach hasn’t been successful. While products like the Glacier and Prinplate Extreme are marketed for use with PA6, I found their performance to be significantly inferior compared to just using an interface layer.
The STYX PA6-GF30 is pretty expensive, costs nearly 100€ per kg. The Fiberon is more affordable, but I personally don’t like the 500g spools and cardboard spools sometimes are problematic in the AMS so Bambu/Sunlu are IMO the best options.
Also I would be curious if you could print this model with your setup because it has nearly no contact area with the bed.
FR4 is a laminate, so essentially sheets of fibers impregnated in resin and pressed together under high temps. Normal PEI sheets are not laminated, they are stainless steel substrates with a direct coating on top. The thermal deformation between the SS and the coating are negligible on the scale we work on, they move as one. For FR4, not so much, as we have adhered only the bottom side, and the Young modulus for SS and FR4 are very different. So the FR4 wants to bend more than the SS, and while the magnet helps, it does so in a limited way.
Flexional rigidity grows as t^3 in respect to height, so if you double the thickness it’s essentially 8 times more resistant to deformation. Thermal gradient is present but doesn’t change much between 1 and 3 mm of FR4. For a 300x300 bed, 100C, a 0.2mm steel plate, and virtually no gradient, top to lowest deformation is 0.015 mm for 1 mm of FR4 and 0.005–0.006 mm for 3 mm. With a thermal gradient of 10C between SS and FR4, those numbers grow respectively to 0.03–0.06 mm and 0.01–0.02 mm. They highest are probably higher due to the discrepancies in the laminates. Those are really approximated calcs.
Thank you for your explanation. However, bending the FR4 would require either bending the entire aluminum build plate or leaving a small air gap between the steel sheet and the magnetic film, despite the magnetic forces at play. I’m uncertain if those forces in a FR4 plate are sufficient to achieve that with a 1mm or 3mm FR4 plate.
That said, even if it would make a drastic difference, with the advent of automatic bed leveling, this discrepancy between the 1mm or 3mm FR4 should be compensated anyway, as the printer performs bed leveling while the bed is heated.
In the past, your points were certainly valid since we typically clamped the bed material directly to the surface without any auto bed leveling features etc. Nowadays with modern printers I can’t see how a 3mm build plate would make any difference and would make you to succeed printing PA compared to a 1mm plate of FR4.
With FR4 you just wait for the temp to get down and the parts pops off. No need for bending (which you wouldn’t be able to do anyway).
with the advent of automatic bed leveling, this discrepancy between the 1mm or 3mm FR4 should be compensated anyway, as the printer performs bed leveling while the bed is heated.
No, not really. Mesh leveling isn’t magical, and can compensate usually only one layer height worth of delta between the lowest and highest peaks (e.g. 0.2 mm across the entire bed for a 0.4mm nozzle). Given that modern beds already have their own issues, you’re essentially doubling or tripling the delta.
The other thing to consider is that Nylon hates to be stretched in ways that it doesn’t want to warp itself. So if the FR4 is not stable, it’s effectively adding it to the warpage of the PA.
In the past, your points were certainly valid since we typically clamped the bed material directly to the surface without any auto bed leveling features etc.
Bed leveling has been available for the best part of ten years…
I’ve successfully printed Sunlu’s easyPA with a PLA Interface layer. Works as well if not better than PETG.The easyPA prints also really nice without the Interface layer but the big advantage is that you don’t need to use the chamber heating, I’ve successfully printed it with an open door. Im also gonna try it with normal PA6 / PA6-GF without chamber heating and PLA and see if that works.
Keep in mind that even though you might be able to print it without chamber heating, the resulting amount of stress in the part, might eventually change the shape of the part.
PA itself is not really good in holding it’s shape under constant load and the CF and GF variants are a bit better in that perspective. So I would also check the shape of you part after a couple of days/weeks to see if it doesn’t deform over time due to the internal stress.
I have the parts set up, but can’t get Bambu Studio to allow slicing even after turning off the “remove restriction” feature in preferences. What else am I missing?
