Large ASA prints warping

Bambu Filament and Accesories
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This is a bit a continuation of I can’t print with Bambu’s ASA using Bambu’s ASA Filament profile where @Njdor8 and @Damocles provided some very helpful print settings, which I tried to apply to my tests. Originally I printed a 2x 250mm long hydrofoil shape that pulled off the bed and warped considerably:

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Since then I’ve concocted a smaller test model so I can run experiments without wasting too much filament. Here are 4 samples:

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I’m getting better results, but I’m wondering what to try next…

The test shape is 200mm x 5mm x 40mm (with some ridges so I can see where it’s warping) and it has an Orca-provided 5mm brim.

The first test piece is Polylite ASA (natural), .4 nozzle, 3 walls, 15% line infill, 150mm/s speed, 260C/90C with the chamber 40-45C. Fans set according to Generic ABS (older version of Orca without ASA profile). One end lifted 1.4mm, the other 1.1mm.

In the same print I had the second test piece (objects printed sequentially) with all the same settings, except speed reduced to 20mm/s (took forever!). It lifted less: .9mm and .6mm. So speed matters but it’s not the solution.

I then ran a fan speed test piece and followed up with the third test piece shown. I set part cooling to 0% (aux was 0% already) and bumped the bed to 100C, limited speed to 50mm/s. The result is .75mm and .3mm: getting better.

Finally, I ran a 4th piece using 3DXTech ASA+CF (costs >2x the Polylite). Temp 255C (max of the recommended range), 100C bed, chamber 40-45C, 50mm/s speed, no fan, left to cool slowly for an hour after being done. This provided another improvement: 0.35mm / 0.2mm. What was interesting is that the test part remained fully adhered to the gold PEI plate but it was warped: it lifted the plate off the bed!

In all cases the tops are perfectly flat and my printer bed is also very flat. It’s nice for the results to get better, but once I scale up to real parts I’m afraid the results will still be only ho-hum. I’m not sure where the answer lies:

  • tweak the settings some more (but what?)
  • try a glass plate or perhaps a CF plate (or do those end up lifting off the bed also?)
  • design the parts so they’re pre-warped in the opposite direction
  • learn how to add stress relief features into the parts (a bit difficult when I need a smooth outer surface)
  • design weak/thin parts to minimize warping and add internal CF stiffening ribs
  • print the foil standing (but that weakens it considerably and there will still be warping)
  • switch to PETG or PETG-CF and deal with UV exposure somehow (I’ll test whether PETG-CF warps less)

Thoughts?

Edits:

  • I hadn’t compared the stiffness of the ASA+CF with the ASA and it’s a significant difference! So perhaps I could print with thinner walls and infill and get the same strength and less warping?
  • Anyone have a recommendation for ASA with CF that is a bit more budget friendly (if less strong) and available in the US? I know of Priline on Amazon and IIID Max.
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Couple of thoughts off the cuff

  1. Design in a thick brim, 1-5mm thick that you have to physically cut off. I’ve done this before and had some success, however your part is just about worse case for warping to be honest so this might be insufficient.

I don’t find that adding the default brim has helped my ASA prints stick better with the texture plate. Usually it’ll just separate from the brim and warp anyways if it’s going to warp. Probably not useless but just my experience.

1.5. Put the leading edge first. This will give you a larger amount of material closer to the base which may reduce the impact of the bending moment that results from shrink in the following layers. You’d probably have to sand the leading edge to prevent any turbulent trip zones afterwards but that’s not a big deal.

  1. Using a spinal warp in CAD, you could easily bias it in the opposite direction to account for warp during print. You would have much weaker plate adhesion which would probably force idea 1 anyways.

  2. 100% infilling often helps prevent warp, but is a poor option for an aerofoil.

  3. PETG or another material (such as annealed PLA - might have too much warp/shrink though) isn’t a bad idea, just throw a thin coat of spray paint over the top to provide UV protection. This is probably the cheapest/easiest way forward and might even make your wing smoother helping reduce boundary layer drag.

  4. If you’re concerned about vertical orientation printing (along wingspan) strength, you could always put long dowel pins made out of steel or wood (if using wood, probably epoxy in place for added stiffness) through the span to stiffen without adding a ton of weight or complexity.

I’d also hazard a guess that with the size of your wing you won’t have any problems with strength since the loads you’re generating aren’t going to be that large.

5.5 - you could take this further and split the wing up into smaller sections and then dowel + epoxy to assemble the whole thing. Finish with a light alcohol vapor smoothing?

  1. Lastly, you could treat the print as the core and fiber/carbon fiber layup over the top. Then burn/remove the core for a very lightweight span. This is probably overkill and too expensive for what you’re wanting to do but is an option.
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Thanks for all the suggestions!!! This is a hydrofoil (really a mast for a motor) so forces are much larger than on an airfoil and weight is less of a factor.

Overall I had hoped to be able to prototype designs quickly without a lot of post-processing and actually had contemplated getting a 3D printer with a larger bed than the X1 but maybe all that doesn’t really work out.

On the other hand, I have the feeling that with a handful more tricks I can get it to where it works for prototypes and I’m learning a lot by trying to push this to the best I can get. In the meantime I wrapped some CF around what I have (this is before applying the epoxy, it’s just tacked on):

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If I have to do a lot of post-processing I’d probably opt for printing a frame with very thin walls that I can wrap with CF.

Quick addition: I printed the same test bar in transparent Sunlu PETG (cheap stuff) and got 0.2mm and 0.3mm warping, so similar to the ASA+CF. The print was fully adhered to the PEI plate and the plate was flat, so it must have bounced after detaching from the plate.

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When using ASA/ABS I use a Brim-Object Gap of 0.0mm with a 5-10mm brim, this usualy works for me with the bed at 100c on my p1p/p1s printers. Also I use Gyroid infill when using ASA/ABS, and pre-heat my chamber.

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Do you print objects >=200mm in size? How much warping do you end up with?

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I had alot of warping before using those settings, BUT anything I print over 200mm in L or W is usualy never over 70mm in height.

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wank to make astroluna floor on my home how i can do that

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Please start a new thread to keep this one on-topic. Thanks! :wink:

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The forces that generate warps are coming from the plastic higher up on the print cooling off more than the plastic nearer the build plate. The plastic shrinks and that pulls in/up on plastic lower down on the print.

If you orient the model with the fatter leading edge of the airfoil on the side nearest the build plate, this will position the thinner area of the print higher up. It’ll cool even faster because it’s thinner, but it won’t produce as much force because there’s less material. This might reduce the warping some.

Also, since it’s the thermal gradient across the vertical axis of the print that produces the warping forces, you can minimize the gradient by lowering the build plate temp to the lowest temp that still results in a successful first layer. Also worth waiting for the build chamber to heat up as much as possible (limited by your patience, I think) before starting the print. I go for 40ºC minimum before starting a ASA/ABS print.

I’m assuming you’ve already turned off all the fans, but if you haven’t, do that too.

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Thanks for the tips!! I have the leading edge up so it prints nicely, if I put it down it will need supports resulting in a shitty surface. I’ll have to try anyway. Pick your poison, I guess…

I’m confused about the build plate temperature. Lots of folks recommend pushing it as high as possible. But I think a lot of that has to do with adhesion. So far adhesion hasn’t been my problem (the ASA+CF even pulled the build plate itself up, off the magnets). But if I lower the build plate temp, doesn’t that increase the delta-T to the freshly printed top layers? I could do a test with 105C plate temp for the first layer and then <90C for the rest…

One potential solution for my airfoil that I hadn’t thought of before might be to extend the tail (bottom of print) by a few mm and then to sand it straight…

Large stuff definitely doesn’t seem to be “design it and hit the print button”…

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Yes. But the print warps because the layers closer to the build plate stay hot while the layers higher up cool faster. Increasing build chamber temp reduces that gradient some. Lowering the build plate temp does the same.

The deformation of the print at the build plate is obvious to see, but the top of the print is going to be deformed, too. As the lower layers lift, the top of the print lifts, too. Every time the nozzle passes over that area the layer height is “squished”. The build plate is mounted on springs, so as the nozzle passes over the lifted region it also pushes down on the print, which compresses the springs, resulting in a lot of tolerance deviation in that area.

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Just a suggestion to try applicable for ASA /.ABS

  • Bed temp set to 110
    Turn on the Bed temp at least 30 Minutes before you start the print or/and chamber temp to reach around 48-50C
    Print temp 260-265 for ABS i use 270 for ASA 255-265
    Speed 70mm/S you may tray 100mm/S i would not go higher
    Assuming in general you have a good adhesion

After the print finishes do not open the chamber door
turn back on the Bed temperature at 100C
Reduce it by 10C once it reaches the set temperature reduce it again , so on to around 60C if you want around 40 is better, then turn off the bed temp . You can write a gcode for that if you want at Machine end code
wait until the bed temperature is almost room temperature do not open the chamber until then

Alternative to the above is just do not open the door just let it cool down slowly

The trick is to cool down very slowly to reduce the internal material pressure
The second trick is to print very slowly so not to build so much pressure as it will release it while you print

Ideally 60C+ chamber temp
EDIT :
The whole procedure is annoyngly long Heating plus cooling
Propper heating 30 to 60Minutes
Propper Cooldown depending on the print size easy 1 hour +

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I’ve been following this thread, adopting the various recommendations but still have warping at corners of large box (200x200x 30mm. Everything goes well until I finish the interior bottom of the box ~10mm. At that point as the walls are remaining, all four plate corners pull up and print is ruined. If I clamp the engineering plate down, then the box plus brim will pop up at the corners.

I am using ESUN ASA - Matte Gray. Based on previous messages in this thread I am doing the following:

  1. Chamber preheated using bed temp of 110 deg. Chamber will only reach 46 deg max. All openings taped over.
  2. Lowered Nozzle temp to 90 deg.
  3. ALL fans off ALL the time.
  4. Max speed 70mm/s all layers

I am open to any additional suggestions. I need to make several of these boxes (Other half is even larger!) So hope I can get this dialed in.

I’ve had no problems with PETG and PETG-CF in the past. But this is driving me nuts and broke.

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Pictures do help…

How much lifting do you get?

I don’t understand “Lowered Nozzle temp to 90 deg”

I just tried Phaetus aeWorthy ASA+GF (in red) and it’s only marginally more expensive than PolyLite ASA. It warps less, maybe half of PolyLite (on a test piece). It doesn’t eliminate warping entirely. (I printed a test bar like in the 3rd photo in the OP.)

I did one print of a part with the bed at 110C and I got the feeling that that’s too hot for this specific filament. It wasn’t adhering well. Vicat temp is supposedly 106C… I then used 100C after that. My chamber temp was a bit over 50C (I preheated with bed at 120C and aux fan at 10%).

For a big box if you want the top of the box on the bed to come out flat I have the feeling that you have to introduce some stress relief features into your model. It’s just not gonna work otherwise.

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Thanks @3dsurfr for quick response. Late night finger fumble. When I said lowered nozzle temp I actually meant bed temp. Did this to follow advice somewhere to print with lowest possible bed temp where still sticks to minimize temp differential between lower levels and faster cooling upper levels. Think this advice came from @RocketSled. Perhaps I do in fact need to go in other direction and try 110 to 120. Attached are photos. This is actually a box like container with two halves. All images are of same half. One is completed base done about a year ago on different printer no longer available. It is mostly ok with just some light warping at corners. I am providing to show what overall should look like, The second is the container base with X1C. Everything stays flat until the interior ‘floor’ is complete and the sidewalls start printing. You can see the nozzle starts dragging in the corners as a result of the warping.

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What I meant was, minimize the difference between the bed and extruder temperatures. Max out the bed temp and drop extrusion temp by 5-10º (also, turn on the build plate heater manually and give the build chamber 30 minutes to get good and toasty-warm before you kick off your print).

Your goal is to keep as much of the print as close to the extrusion temp as possible. Of course, the bed and chamber can’t get anywhere near the extrusion temp and the print is going to cool and shrink no matter what you do. But the areas that have the highest temperature delta between the extruded and cooled states will shrink the most.

That’s why prints warp. The areas further away from the build plate cool more/faster than the areas nearer the build plate. As these areas cool they shrink/contract, which causes the print to “curl”. Higher up features pull “inward” as they shrink and that produces an upward force on the areas of the print lower down. We call it “warping” but I think a more descriptive term is “potato chipping”. :slight_smile:

It’s why an enclosed/heated print chamber is really kind of mandatory for some filaments like ABS/ASA/PA/PETG, which all have a fairly high coefficient of thermal expansion, but not PLA.

Sorry for any confusion my previous comments caused.

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@RocketSled Thanks for clarifying. And no apologies necessary. You were quite clear about what is occurring during the print process. I just misinterpreted some of it. I’ll be out of town on business until early next week but when I return I will try the following:

  1. Preheat chamber by setting bed temp to ~120deg to hopefully get close to 60 deg chamber temp. I’ve previously struggled to get 45-46 with 110 deg. But will try to get as high as possible and let cook for at least 30-45 min before I start the print. All doors etc. taped shut.
  2. Back off bed temp to ?? perhaps 100 deg or 95? Don’t think 120 deg will work. Thoughts?
  3. Current nozzle temp has been 260. I’ll try 250-255 and see if that will still work.
  4. All fans off.
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  1. yes.
  2. no.
  3. yes.
  4. yes.

Go like 5-10º higher than the minimum recommended extrusion temp for your filament.

I think I’ve been running ASA at 250ºC.

110ºC should be the max your bed will let you set it to.

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The US bed can go to 120C. Above 105C you get into softening temps depending on filament details, so I don’t think keeping the bed at 120C for printing is wise, but something to perhaps experiment with.

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Thanks. I’ll give it a try when I get back next week. In US so should be able initially set to 120C then back off after I max out chamber temp for 30 min or so.

Will check recommended extrusion temp and go for that. Perhaps run a temp tower first.

Only thing not clear to me, bed temp - when ready to print lower to minimum that works such as 90-95 or something higher?

Thanks again.