<p>Cooling duct design is not well understood by either the 3D printer OEMs (exceptions may apply) nor by the aftermarket cooling options or most of the  homebrew designs.</p>
<p>The problem is the lack of the understanding in aerodynamic design. Note that the fans that we use to produce the cooling flows are pushing flow, they do not create a large pressure difference. So with not too much pressure difference you should avoid long ducts and sharp bends in the flow path, narrowing of duct annuli or (you should) narrowing the duct annuli when air is bled out.</p>
<p>Looking at many of the options available, it is clear that many of these design rules are not taken into account.</p>

CC BY-SA 4.0
2022-04-27T05:24:31.670Z
+1. Add to that that even normal 3D printing design rules are hardly ever followed - being support-free with no overhangs and reasonable chamfers, making holes properly printable with angled roofs, easy fastener placement etc.
towe
CC BY-SA 4.0
2022-04-28T08:17:33.583Z
@towe you mean like [this primer I wrote?](https://3dprinting.stackexchange.com/questions/6726/what-special-considerations-must-be-taken-when-designing-parts-for-3d-printing/6830#6830)
Trish
CC BY-SA 4.0
2022-04-29T13:03:28.403Z
@0scar So it seems as if you are saying that the part cooling mods that are out there are not useful almost detrimental to 3D printing. Am I correct?
agarza
CC BY-SA 4.0
2022-04-29T21:17:16.750Z
@agarza I am saying that there are cooling mods/designs out there that don't adhere to proper aerodynamic design. If that is detrimental to the print quality is another question answered below. What I do know is that the fan nozzle on the Anet A8 was narrowing so much that virtually no air bled out. Similar to most of the ring around the nozzle style cooling ducts, for every hole the main channel should be narrowed else the air will slow down making it way less effective. Most of the ducts have a constant area cross section even when air is bled.
0scar
CC BY-SA 4.0
2022-04-29T22:11:40.483Z
@0scar Very true. I was looking at the Petsfang and Hero Me. David Crosslink recently had an interview on YouTube with the designer of the Hero Me. I'm not well versed in aerodynamics but it sounded like he designed the Hero Me to provide better airflow around the nozzle.
agarza
CC BY-SA 4.0
2022-04-30T21:29:29.913Z
@agarza The answer was meant to be generic and doesn't specifically address the cooling options that are mentioned. For the Hero Me or at least some of the available options seem okay, short distance from fan to exit, but they still have a steep convergent nozzle. The petsfang has long ducting and 90° bends. Print them, try them modify them !
0scar
CC BY-SA 4.0
2022-04-26T07:12:40.767Z
2022-04-26T07:12:40.767Z
0scar
<p>The best 3D printed cooling solution actually is not used generally - and it can be rather loud. I am talking pretty much the very same setup one uses in a CNC-mill to spray or mist cooling liquid on the item. That's either flood cooling (with a full jet) or mist cooling (with a mist). Just, in this case, using air hoses and a compressor or air pump, it's best called &quot;airblast&quot;.</p>
<p>In such a setup, all the ducts are extruded tubings, the nozzles are metal and the only 3D printed part is a holder for these parts. But how is this loud? It's often loud because this setup needs a compressor to run and push air through the air hoses. And compressors can be rather loud.</p>

CC BY-SA 4.0
2022-04-26T14:36:37.950Z
(The "spray cooling" is called mist cooling, which contrasts flood cooling in terms of CNC Milling) <- that's just for your general knowledge Trish.
user77232
CC BY-SA 4.0
2022-04-26T14:42:29.683Z
@user77232 Yes, one could use a dry Mist Cooling system, but I actually meant either setup: their setup is close enough to one another to convey the idea. Some people have turned [aquarium pumps](http://www.tridimake.com/2016/05/3d-printing-cooling-with-air-pump-aquarium.html) into coolers, though the effectively is questionable.
Trish
CC BY-SA 4.0
2022-04-26T15:03:22.913Z
At least several people doing high performance printing are using CPAP systems for this rather than a full-fledged compressor.
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2022-04-26T12:52:56.790Z
2022-04-26T14:47:32.627Z
2022-04-26T14:47:32.627Z
Trish
<p>Part cooling is essential to print at any decent <em>vertical speed</em> (layers per second), which is critical if you do rapid prototyping of small parts or vase mode prints. This is because you can't (repeatedly) print on top of material that hasn't yet cooled enough to be rigid; if you do, after a few layers, you'll find nothing is in the right place and it's all a bunch of goo getting dragged around by the nozzle. In fact, if the part is small enough you might not be able to print it at all. That's because, while slicers have features to slow down to guarantee a minimum layer time for cooling purposes, if the hot nozzle sticks around in the vicinity of a tiny part the whole time, just the heat from the nozzle will keep it from properly solidifying.</p>
<p>The Ender 3 (and as far as I know, the v2 as well, along with just about every other Creality printer) has <em>pitiful</em> stock cooling. It's off-center from the nozzle, and aimed more at the nozzle itself rather than the part below it, so that it saps heat out of the hotend (making the heater work harder and reducing your max achievable flow) at the same time it's (barely) cooling the print. So upgrading it is desirable. But, as you've guessed, there are cons too.</p>
<ol>
<li><p>Some, especially those utilizing the stock 4010 fan, <em>reduce airflow</em> by constricting the airway too much. The 4010 does not really have the power to compress the air much, so if the airway cross-sectional area decreases along the way, that will reduce flow. Does the increase in focus/delivery to the right place make up for the lost flow? Maybe.</p>
</li>
<li><p>Some <em>focus the air too narrowly</em> while increasing its pressure, delivering high-pressure air to a still molten point on the print. This can actually cause the extruded material to bend in the direction the air is pressing it before it cools enough to solidify, giving an inaccurate print.</p>
</li>
<li><p>Large fans and ducts add mass to the toolhead, which can increase ringing, especially if they're not sufficiently rigid.</p>
</li>
<li><p>Many of the cooling mods mount awkwardly to the toolhead in ways that interfere with the motion of the carriage, reducing total build volume.</p>
</li>
<li><p>If the cooling mod blows on/over the heater block, it can reduce melting performance and pour heat onto the part you're trying to cool. Most try to avoid doing this, but you may find you want additional insulation around the block if you use more powerful part cooling.</p>
</li>
</ol>
<p>Some people will also tell you that &quot;too much cooling&quot; will harm your print quality, hurting layer adhesion, making the print warp, etc. I use a rather extreme cooling system and have not encountered such problems that can't be remedied with a slight increase to the nozzle temperature, yielding better overall quality and equal strength to what I would have gotten with lower fan. But I print just PLA, PETG, and TPU, so it's likely that this could be an issue with other materials like ABS or nylon. If so you can always reduce the fan speed.</p>

CC BY-SA 4.0
2022-04-26T07:53:21.470Z
I've added an answer to focus on aerodynamic design as you touch under `1.`. Great answer and good insight in that the poor designs restricting airflow may cause an "inadverse" effect of good prints! :-)
0scar
CC BY-SA 4.0
2022-04-26T14:34:03.350Z
In the context of a heated build chamber, part cooling is not necessary
user77232
CC BY-SA 4.0
2022-04-26T15:01:12.183Z
@user77232: Depending on what materials and what print speed, it may be needed.
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2022-04-26T04:07:07.307Z
2022-04-26T04:07:07.307Z
R.. GitHub STOP HELPING ICE
<p>In my previous research for mods for my Ender 3v2, I came across the topic of part cooling mods. The two most common are the Petsfang and Hero Me sets.</p>
<ol>
<li><p>What are the pros and cons of third-party/DIY part cooling mods?</p>
</li>
<li><p>What benefit does having a third-party/DIY part cooling mod provide?</p>
</li>
</ol>

CC BY-SA 4.0
2022-04-26T13:19:46.873Z
What makes you think your printer has a cooling problem? Fixing things that aren't broke seems to be a staple of DIY 3d printing mods
Kilisi
CC BY-SA 4.0
2022-04-26T14:16:23.550Z
@Kilisi I never intimated that I had a cooling problem. In my research about mods, I came across part cooling mods and thought about asking here to get better informed. Additionally, mods can be done to improve performance depending on how you look at things.
agarza
CC BY-SA 4.0
2022-04-29T05:12:50.750Z
a small box fan to the side of the printer hits the top layer constantly, unlike a fan attached to the nozzle, which only cools during the brief period that the head is hovering above.
dandavis
<print-fan>
Pros/Cons of 3D printed part cooling mods
agarza
# Pros/Cons of 3D printed part cooling mods

(Asked by: username_0 on 2022-04-26)

In my previous research for mods for my Ender 3v2, I came across the topic of part cooling mods. The two most common are the Petsfang and Hero Me sets.

1. What are the pros and cons of third-party/DIY part cooling mods?
2. What benefit does having a third-party/DIY part cooling mod provide?

**Tags:** print-fan
> **Comments:**
> **username_1**: What makes you think your printer has a cooling problem? Fixing things that aren't broke seems to be a staple of DIY 3d printing mods  
> **username_0**: @Kilisi I never intimated that I had a cooling problem. In my research about mods, I came across part cooling mods and thought about asking here to get better informed. Additionally, mods can be done to improve performance depending on how you look at things.  
> **username_2**: a small box fan to the side of the printer hits the top layer constantly, unlike a fan attached to the nozzle, which only cools during the brief period that the head is hovering above.  

---

## 3 answers

### Answer by username_3 on 2022-04-26. Score: 5

Cooling duct design is not well understood by either the 3D printer OEMs (exceptions may apply) nor by the aftermarket cooling options or most of the homebrew designs.

The problem is the lack of the understanding in aerodynamic design. Note that the fans that we use to produce the cooling flows are pushing flow, they do not create a large pressure difference. So with not too much pressure difference you should avoid long ducts and sharp bends in the flow path, narrowing of duct annuli or (you should) narrowing the duct annuli when air is bled out.

Looking at many of the options available, it is clear that many of these design rules are not taken into account.

> **Comments:**
> **username_4**: +1. Add to that that even normal 3D printing design rules are hardly ever followed - being support-free with no overhangs and reasonable chamfers, making holes properly printable with angled roofs, easy fastener placement etc.  
> **username_5**: @towe you mean like [this primer I wrote?](https://3dprinting.stackexchange.com/questions/6726/what-special-considerations-must-be-taken-when-designing-parts-for-3d-printing/6830#6830)  
> **username_0**: @0scar So it seems as if you are saying that the part cooling mods that are out there are not useful almost detrimental to 3D printing. Am I correct?  
> **username_3**: @agarza I am saying that there are cooling mods/designs out there that don't adhere to proper aerodynamic design. If that is detrimental to the print quality is another question answered below. What I do know is that the fan nozzle on the Anet A8 was narrowing so much that virtually no air bled out. Similar to most of the ring around the nozzle style cooling ducts, for every hole the main channel should be narrowed else the air will slow down making it way less effective. Most of the ducts have a constant area cross section even when air is bled.  
> **username_0**: @0scar Very true. I was looking at the Petsfang and Hero Me. David Crosslink recently had an interview on YouTube with the designer of the Hero Me. I'm not well versed in aerodynamics but it sounded like he designed the Hero Me to provide better airflow around the nozzle.  
> **username_3**: @agarza The answer was meant to be generic and doesn't specifically address the cooling options that are mentioned. For the Hero Me or at least some of the available options seem okay, short distance from fan to exit, but they still have a steep convergent nozzle. The petsfang has long ducting and 90° bends. Print them, try them modify them !  

---

### Answer by username_5 on 2022-04-26. Score: 2

The best 3D printed cooling solution actually is not used generally - and it can be rather loud. I am talking pretty much the very same setup one uses in a CNC-mill to spray or mist cooling liquid on the item. That's either flood cooling (with a full jet) or mist cooling (with a mist). Just, in this case, using air hoses and a compressor or air pump, it's best called "airblast".

In such a setup, all the ducts are extruded tubings, the nozzles are metal and the only 3D printed part is a holder for these parts. But how is this loud? It's often loud because this setup needs a compressor to run and push air through the air hoses. And compressors can be rather loud.

> **Comments:**
> **username_6**: (The "spray cooling" is called mist cooling, which contrasts flood cooling in terms of CNC Milling) <- that's just for your general knowledge Trish.  
> **username_5**: @user77232 Yes, one could use a dry Mist Cooling system, but I actually meant either setup: their setup is close enough to one another to convey the idea. Some people have turned [aquarium pumps](http://www.tridimake.com/2016/05/3d-printing-cooling-with-air-pump-aquarium.html) into coolers, though the effectively is questionable.  
> **username_7**: At least several people doing high performance printing are using CPAP systems for this rather than a full-fledged compressor.  

---

### Answer by username_7 on 2022-04-26. Score: 2

Part cooling is essential to print at any decent *vertical speed* (layers per second), which is critical if you do rapid prototyping of small parts or vase mode prints. This is because you can't (repeatedly) print on top of material that hasn't yet cooled enough to be rigid; if you do, after a few layers, you'll find nothing is in the right place and it's all a bunch of goo getting dragged around by the nozzle. In fact, if the part is small enough you might not be able to print it at all. That's because, while slicers have features to slow down to guarantee a minimum layer time for cooling purposes, if the hot nozzle sticks around in the vicinity of a tiny part the whole time, just the heat from the nozzle will keep it from properly solidifying.

The Ender 3 (and as far as I know, the v2 as well, along with just about every other Creality printer) has *pitiful* stock cooling. It's off-center from the nozzle, and aimed more at the nozzle itself rather than the part below it, so that it saps heat out of the hotend (making the heater work harder and reducing your max achievable flow) at the same time it's (barely) cooling the print. So upgrading it is desirable. But, as you've guessed, there are cons too.

1. Some, especially those utilizing the stock 4010 fan, *reduce airflow* by constricting the airway too much. The 4010 does not really have the power to compress the air much, so if the airway cross-sectional area decreases along the way, that will reduce flow. Does the increase in focus/delivery to the right place make up for the lost flow? Maybe.
2. Some *focus the air too narrowly* while increasing its pressure, delivering high-pressure air to a still molten point on the print. This can actually cause the extruded material to bend in the direction the air is pressing it before it cools enough to solidify, giving an inaccurate print.
3. Large fans and ducts add mass to the toolhead, which can increase ringing, especially if they're not sufficiently rigid.
4. Many of the cooling mods mount awkwardly to the toolhead in ways that interfere with the motion of the carriage, reducing total build volume.
5. If the cooling mod blows on/over the heater block, it can reduce melting performance and pour heat onto the part you're trying to cool. Most try to avoid doing this, but you may find you want additional insulation around the block if you use more powerful part cooling.

Some people will also tell you that "too much cooling" will harm your print quality, hurting layer adhesion, making the print warp, etc. I use a rather extreme cooling system and have not encountered such problems that can't be remedied with a slight increase to the nozzle temperature, yielding better overall quality and equal strength to what I would have gotten with lower fan. But I print just PLA, PETG, and TPU, so it's likely that this could be an issue with other materials like ABS or nylon. If so you can always reduce the fan speed.

> **Comments:**
> **username_3**: I've added an answer to focus on aerodynamic design as you touch under `1.`. Great answer and good insight in that the poor designs restricting airflow may cause an "inadverse" effect of good prints! :-)  
> **username_6**: In the context of a heated build chamber, part cooling is not necessary  
> **username_7**: @user77232: Depending on what materials and what print speed, it may be needed.  

---

