<p>The <a href="https://web.archive.org/web/20231214080914/https://colorfabb.com/media/datasheets/tds/colorfabb/TDS_E%20ColorFabb%20allPHA.pdf" rel="nofollow noreferrer">technical datasheet for ColorFabb's &quot;allPHA&quot; filament</a> <a href="https://colorfabb.com/media/datasheets/tds/colorfabb/TDS_E%20ColorFabb%20allPHA.pdf" rel="nofollow noreferrer">[original]</a> says the following:</p>
<blockquote>
<p>Contrary to most 3D printing materials allPHA is best printed on a
cold plate, so no active heating is required. A heated plate will
induce crystallization, which will lead to warping of the bottom
layers.</p>
<p>We advise using 100% cooling starting on the second layer. This helps
set the model by slowing down crystallization of the allPHA matrix.</p>
</blockquote>
<p>So apparently, you have to cool it down quickly to freeze it in its amorphous form. Cooling too slowly will give it time to form a crystal lattice, shrinking in the process. This shrinking of the upper layers then exerts a force that pulls the corners of the lower layers upwards, which manifests as warping.</p>
<p>So my guess would be: <strong>Add more cooling.</strong> As mentioned in the comments, printing slower might help, because it gives the part cooling fan more time to blow on the printed lines, thus cooling them faster.</p>
<p>PS: Additionally, different materials require different bed materials. The fact that PLA sticks to your plate does not mean that other materials will stick just as well. The datasheet linked above suggests &quot;3DLac / Diluted wood glue&quot; for treating the bed, so that might be worth a try. Wood glue is often PVA-based, the same as many glue sticks, so that might be a good idea as well.</p>

CC BY-SA 4.0
2023-12-14T14:38:26.350Z
I would also advise printing slower and see if it helps. It can be helpful if cooling is on 100%.
kosteklvp
CC BY-SA 4.0
2023-12-28T21:34:41.957Z
Thanks for all tips. I did a few more attempts today. Slowed down printing speed to 50%, heated bed of 50C, unheated bed, smaller Z-offset, 100% cooling from first layer, 0% cooling from first layer, glue stick. Adhesion is horrible. After three or four layers all comes lose. I didn't have a single successful print with PHA so far. Other ideas? PLA works great on that machine with almost all mentioned settings.
Bob Ortiz
CC BY-SA 4.0
2023-12-14T08:12:46.343Z
2023-12-15T04:42:00.800Z
2023-12-15T04:42:00.800Z
Fritz
<p>I'm experimenting with a new type of filament, 100 % polyhydroxyalkanoates (<strong>PHA</strong>). However, per the manufacturer's instructions I'm using a <strong>PLA</strong> profile in Cura and with the only change being a 200 °C nozzle on a cold, <strong>unheated carborundum glass bed</strong> using a well-calibrated Creality Ender 3 V2. Fan speed at 100 % from the first layer.</p>
<p>The whole setup works flawlessly with PLA at 210 °C with a heated bed at 35 °C. My PLA prints are generally hard to remove, even after cooling down the bed, sticking too well, despite not using glue sticks or adhesives. So, I assume that adhesion cannot be the issue.</p>
<p>For PHA, the first layers look excellent, but after some time, the result is extreme warping as shown below:</p>
<p><a href="https://i.sstatic.net/ltYSr.jpg" rel="nofollow noreferrer" title="sideview of extreme PHA warping with unheated bed"><img src="https://i.sstatic.net/ltYSr.jpg" alt="sideview of extreme PHA warping with unheated bed" title="sideview of extreme PHA warping with unheated bed" /></a></p>
<p>How is it possible for a print to warp on an unheated bed in a room with a stable room temperature of 19 °C and humidity of 45 %?</p>
<p><a href="https://i.sstatic.net/MFx3B.jpg" rel="nofollow noreferrer" title="top view of PH print on unfinished print on unheated bed"><img src="https://i.sstatic.net/MFx3B.jpg" alt="top view of PH print on unfinished print on unheated bed" title="top view of PH print on unfinished print on unheated bed" /></a></p>
<p>The model used (although print canceled) was <a href="https://www.thingiverse.com/thing:4670018" rel="nofollow noreferrer">Filament Swatch</a> from Thingiverse.com.</p>
<p>Example of the same model, printed on the same machine, with the same settings but <strong>using recycled PLA and a heated bed</strong>:</p>
<p><a href="https://i.sstatic.net/6aQNq.jpg" rel="nofollow noreferrer" title="successful PLA print"><img src="https://i.sstatic.net/6aQNq.jpg" alt="successful PLA print" title="successful PLA print" /></a></p>

CC BY-SA 4.0
2023-12-02T16:31:53.610Z
What is your question? Just "how is it possible?" Or are you looking for advice on how to print this material?
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2023-12-02T17:10:18.363Z
Fair enough. Both, but they shouldn't be two separate questions. I'm surprised by how this is possible because warping is, by definition, the result of a heated bed, which is absent here. And, of course, by understanding the cause, we would be able to fix it, too, which is the goal.
Bob Ortiz
CC BY-SA 4.0
2023-12-02T18:04:45.423Z
@BobOrtiz don't know what definition you're using, but warping in, for example, ABS, can happen at any height, heated bed or not. If anything, I find heated bed help prevent it.
Mołot
CC BY-SA 4.0
2023-12-02T18:08:06.670Z
Then perhaps my understanding of warping is incorrect. Feel free to answer the question to clarify.
Bob Ortiz
CC BY-SA 4.0
2023-12-03T00:24:39.087Z
Warping is not "by definition" the result of a heated bed. Warping is the result of material shrinking as it cools, and having the opportunity to do so unconstrained by other forces (like adhesion to the bed, or rigidity of other material it's bonded to that's already cooled). The reason PLA sometimes warps more during printing with an overly hot bed is that the heat from the bed prevents the lower layers from *ever* becoming rigid, so they can't constrain the material laid on top of them.
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2023-12-14T15:57:21.843Z
Just out of curiosity, which brand of PHA filament are you using? According to Wikipedia, PHA is a very broad category of polymers with wildly different mechanical properties and melting points, so the brand probably matters a lot.
Fritz
CC BY-SA 4.0
2023-12-14T16:25:36.480Z
I'm using 'allPHA' from colorFabb.com. https://colorfabb.com/filaments/materials/pha-filaments/pha
Bob Ortiz
<pla><filament><warping>
How is it possible for (PHA) prints to warp on an unheated bed?
Bob Ortiz
# How is it possible for (PHA) prints to warp on an unheated bed?

(Asked by: username_0 on 2023-12-02)

I'm experimenting with a new type of filament, 100 % polyhydroxyalkanoates (**PHA**). However, per the manufacturer's instructions I'm using a **PLA** profile in Cura and with the only change being a 200 °C nozzle on a cold, **unheated carborundum glass bed** using a well-calibrated Creality Ender 3 V2. Fan speed at 100 % from the first layer.

The whole setup works flawlessly with PLA at 210 °C with a heated bed at 35 °C. My PLA prints are generally hard to remove, even after cooling down the bed, sticking too well, despite not using glue sticks or adhesives. So, I assume that adhesion cannot be the issue.

For PHA, the first layers look excellent, but after some time, the result is extreme warping as shown below:

[![sideview of extreme PHA warping with unheated bed](https://i.sstatic.net/ltYSr.jpg "sideview of extreme PHA warping with unheated bed")](https://i.sstatic.net/ltYSr.jpg "sideview of extreme PHA warping with unheated bed")

How is it possible for a print to warp on an unheated bed in a room with a stable room temperature of 19 °C and humidity of 45 %?

[![top view of PH print on unfinished print on unheated bed](https://i.sstatic.net/MFx3B.jpg "top view of PH print on unfinished print on unheated bed")](https://i.sstatic.net/MFx3B.jpg "top view of PH print on unfinished print on unheated bed")

The model used (although print canceled) was [Filament Swatch](https://www.thingiverse.com/thing:4670018) from Thingiverse.com.

Example of the same model, printed on the same machine, with the same settings but **using recycled PLA and a heated bed**:

[![successful PLA print](https://i.sstatic.net/6aQNq.jpg "successful PLA print")](https://i.sstatic.net/6aQNq.jpg "successful PLA print")

**Tags:** pla, filament, warping
> **Comments:**
> **username_1**: What is your question? Just "how is it possible?" Or are you looking for advice on how to print this material?  
> **username_0**: Fair enough. Both, but they shouldn't be two separate questions. I'm surprised by how this is possible because warping is, by definition, the result of a heated bed, which is absent here. And, of course, by understanding the cause, we would be able to fix it, too, which is the goal.  
> **username_2**: @BobOrtiz don't know what definition you're using, but warping in, for example, ABS, can happen at any height, heated bed or not. If anything, I find heated bed help prevent it.  
> **username_0**: Then perhaps my understanding of warping is incorrect. Feel free to answer the question to clarify.  
> **username_1**: Warping is not "by definition" the result of a heated bed. Warping is the result of material shrinking as it cools, and having the opportunity to do so unconstrained by other forces (like adhesion to the bed, or rigidity of other material it's bonded to that's already cooled). The reason PLA sometimes warps more during printing with an overly hot bed is that the heat from the bed prevents the lower layers from *ever* becoming rigid, so they can't constrain the material laid on top of them.  
> **username_3**: Just out of curiosity, which brand of PHA filament are you using? According to Wikipedia, PHA is a very broad category of polymers with wildly different mechanical properties and melting points, so the brand probably matters a lot.  
> **username_0**: I'm using 'allPHA' from colorFabb.com. https://colorfabb.com/filaments/materials/pha-filaments/pha  

---

## 1 answers

### Answer by username_3 on 2023-12-14. Score: 4

The [technical datasheet for ColorFabb's "allPHA" filament](https://web.archive.org/web/20231214080914/https://colorfabb.com/media/datasheets/tds/colorfabb/TDS_E%20ColorFabb%20allPHA.pdf) [[original]](https://colorfabb.com/media/datasheets/tds/colorfabb/TDS_E%20ColorFabb%20allPHA.pdf) says the following:

> Contrary to most 3D printing materials allPHA is best printed on a
> cold plate, so no active heating is required. A heated plate will
> induce crystallization, which will lead to warping of the bottom
> layers.
>
> We advise using 100% cooling starting on the second layer. This helps
> set the model by slowing down crystallization of the allPHA matrix.

So apparently, you have to cool it down quickly to freeze it in its amorphous form. Cooling too slowly will give it time to form a crystal lattice, shrinking in the process. This shrinking of the upper layers then exerts a force that pulls the corners of the lower layers upwards, which manifests as warping.

So my guess would be: **Add more cooling.** As mentioned in the comments, printing slower might help, because it gives the part cooling fan more time to blow on the printed lines, thus cooling them faster.

PS: Additionally, different materials require different bed materials. The fact that PLA sticks to your plate does not mean that other materials will stick just as well. The datasheet linked above suggests "3DLac / Diluted wood glue" for treating the bed, so that might be worth a try. Wood glue is often PVA-based, the same as many glue sticks, so that might be a good idea as well.

> **Comments:**
> **username_4**: I would also advise printing slower and see if it helps. It can be helpful if cooling is on 100%.  
> **username_0**: Thanks for all tips. I did a few more attempts today. Slowed down printing speed to 50%, heated bed of 50C, unheated bed, smaller Z-offset, 100% cooling from first layer, 0% cooling from first layer, glue stick. Adhesion is horrible. After three or four layers all comes lose. I didn't have a single successful print with PHA so far. Other ideas? PLA works great on that machine with almost all mentioned settings.  

---

