The Physics of why your 3D Prints Warp, and what to do about it

Warping and delamination are recurring problems in FDM 3D printing for higher temperature materials such as ABS, Polycarbonate, Nylon, PEI and PEEK. Here I show a basic physics model to help understand what exactly causes warping, and based on that what you can do about it. It also explains why Polycarbonate warps much more than PLA, even though their coefficients of thermal expansion are nearly identical at 69 and 68 microns per meter per Kelvin respectively.

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[theresinsamurai]

Thank you for the math that reinforces what we all think occurs.

Running primarily ABS, it was a must to have an enclosure and running higher bed temps.

I'm running 250c on the nozzle and 125c on the bed (Creality CR10s-300) currently with outstanding results just incase someone else is looking at the same setup~

[jesuschal]

What about increasing the temperature of the bed after first layer (or X first layers)? How much would it help?

[franksonjohnson]

Just yesterday my roommate asked me why prints warp and I only had a vague, soupy answer. Thanks to you my answer has cooled past the glass point and solidified.

[Larock-wuuu]

Great explanqtion, thank you! A follow-up video where you explain the effect of bed heating would be awesome.

[collectd]

Thank you for this amazing explanation! The only part I am a bit confused at is when you said you can reduce the extrusion rate in order to close the gap in temperature difference between the new and previous layers. I understand increasing the temp will allow the previous layer to catch up before the first layer reaches tg temp, but m confused on how reducing extrusion rate would have the same effect? Thank you again for this video it has really helped my production. I have found that printing at 205c vs 190c the pla prints tend to be less heat resistant and have a lower tq the hotter you print them.

I reduced my print speed to 75mms @190c from 90mms and it did reduce warping a bit. If I had a volcano nozzle with a much larger melt zone would switching to that and going back to 90mms have the same result? Curious your thoughts and I appreciate any explanation to help with my confusion

[omnicogitosum]

Good job!. Thank you for this explanation.

[ThVG]

Great explanation. I assume it wouldn't matter on smaller prints, but would printing the second layer when the lower layer hasn't fully cooled yet also prevent warping, or does the lower layer reach ambient temperatures too fast for it to matter even on smaller prints?

[EphiBlanshey]

Thanks for the clear explanation. Can you please clarify why printing slower would make a difference? Assuming the ambient, nozzle, and bed temperatures are the same, printing slower would still yield the same temperatures all around, no? If anything it would start laying down the next layer sooner before the previous cools down more.

[GustafB]

The idea with IR lights on the hotend is really interesting, does anyone know if that has been tested practically and what results were?

[woodwaker]

A great explanation, makes sense. thanks for doing this video

[Felipe-twwg]

So it seems more temperature at the hot end would reduce warping by increasing the lower layer more closer into the Glass Transition temperature, and hence, let it flow instead of curl? Seems counterintuitive but interesting nonetheless... I will try it out tonight with a warping print that is driving me nuts.

Thank you for the explanation!

[SniperAngle]

This is weird but i was printing a 3dbenchy and encountered a problem I've had for a while now. My set up is a 0.4mm nozzle ender 3 printing PETG mostly at a bed temp of 85~90C cause i find it gives better bed adhesion, and the issue is that on certain prints I would get this absolutely horrendous warping ~6-8mm above the build plate. Any sort of corner would just begin to curl up and inwards on itself, and I tried everything suggested in this vid short of using an enclosure. I even slowed prints all the way to 25% and i still get this warping. Curiously, it seems to happen only for thinner layer heights, when i bump it up to 0.24 and above, this problem reduces or goes away entirely, but thats obviously not a good fix for the problem. i don't have this problem on my much faster klipper printer either, regardless of the layer height at the same bed temps. I read something in a comment on another video, which was to lower bed temp, i tried it, lowering to 72C and that reduced my warping by a lot. Whats the explanation for this? Obviously closer to the bed, the high temp reduces warpage, and at a certain height, the warping would initiate due to the lower temperature, but why does it diminish when i use a lower bed temp from the start, very fast print speed or thicker layers?

[grzesiekx]

what if the print is warping to the top, not bottom? Everywhere on youtube everybody shows the same thing but actually in reality there are some other deformations, which are preventing me from buying a 3d printer! I use it sometimes when it is available but never bought one because of that. If I have to print a part that has to fit perfectly into something and instead of a straight line looks likne a banana it doesn't make any sens to buy a 3d printer. Everbody prints usuless things but it is very rare that somebody prints something usfull but in this scenario you can see the reality what 3d printer has really to offer (or not).

[laboratoriodorato]

I wish I had teachers that made me this interested on classes. Great explanation, now all the heated enclosures makes sense fo me (beginner at 3d print). Thx for the great video

[MauricioHernandez-deis]

There Is a commercial 3d printer with an array of uv lights, have u seen it?

[MihaiAndreiStanimir]

You can upload this on IGTV so we can share it on Insta 😉

[pixiepaws]

The exponential temperature decay is due to the nature of thermal energy transfer being proportional to the temperature via W/m·K, not because of your explanation.