<p>The density of the filament can be specified in the material model of the filament in Cura (Preferences -&gt; Configure Cura... -&gt; Materials and click on the material/filament you are using to slice your model for PETG), look at the value behind <em>Density</em>, the PETG filament I use is using 1.28 g/cm³ (<a href="https://colorfabb.com/petg-economy-black" rel="nofollow noreferrer">PETG Economy Black -&gt; Specification &gt;</a>).</p>
<p><a href="https://i.sstatic.net/vy283.png" rel="nofollow noreferrer" title="Cura materials window"><img src="https://i.sstatic.net/vy283.png" alt="Cura materials window" title="Cura materials window" /></a></p>
<p>This field is user editable, so you can change it to your needs. Cura calculates the weight based on the deposited volume.</p>

CC BY-SA 4.0
2021-04-22T11:24:30.887Z
Thanks for your answer: I've setted the density to 1.27 , but I'm now getting 37gr, which leads to a bigger difference. Is there any other possible problem?
Leviand
CC BY-SA 4.0
2021-04-22T15:22:18.833Z
This setting is used to allow the viewer to determine expected filament use for the print. As you've already discovered, an inaccurate figure will present a disparity between the displayed value and the weight of the print. Changing the numbers will only provide for a value difference, not an operational difference. The other answer (currently) is not likely to be correct, unless you are having model quality problems.
fred_dot_u
CC BY-SA 4.0
2021-04-22T18:09:45.653Z
@fred_dot_u actually I'm not having a quality problem: I'm only trying to understand if my printer is printing correctly or if something is not right setted. This difference has raised a warning in my mind...
Leviand
CC BY-SA 4.0
2021-04-22T18:14:19.360Z
I didn't think you were having a problem with quality, as that would have taken priority, in my opinion. The answer referencing underextrusion appears to be off-base for that reason. If you use trial and error to enter a weight value in the settings, until you get something that matches closely enough, you'll have done no harm.
fred_dot_u
CC BY-SA 4.0
2021-04-22T08:22:36.863Z
2021-04-22T08:22:36.863Z
0scar
<p>Likely underextrusion. The Ender 3's extruder is particularly bad at PETG and slips a lot unless you go really slow, like 3 mm³/s (about 40 mm/s at 0.2 mm layers and 0.4 mm line width) or lower.</p>
<p>For a long time I thought this was a limitation of the material, at least without a really powerful hotend, and wondered why anyone liked it. But after replacing the extruder on my Ender 3 with one that grips the filament much better (among other differences) I can extrude at several times that rate with no extrusion issues.</p>
<p>My extruder has a lot of differences from the stock Creality one that might be making a difference. It's (remote) direct drive, has a cut-out hobbed gear that wraps partly around the filament tensioned rigidly rather than with a spring, and has net 10:1 reduction gearing. I suspect the hobbed gear configuration makes the biggest different to increased PETG printing capability but I'm not sure. Here's a picture of what I'm talking about</p>
<p><img src="https://i.sstatic.net/NxSQx.jpg" alt="hobbed filament gears" /></p>

CC BY-SA 4.0
2021-04-22T12:38:37.570Z
Actually I'm printing at 40mm/s , because that's the only way I've found to be able to work with petg and ender 3... and the first layer I'm lowering it to 10mm/s ...
Which extruder are you suggesting to upgrade to?
Leviand
CC BY-SA 4.0
2021-04-22T13:31:41.677Z
I'm not making a particular recommendation because there are lots of factors to weight choosing what you want and product recommendations are off topic for this site. I have a flex3drive remote direct drive but it's some work getting it setup well. Mainly for this specific problem I suspect you need either double hobbed gears (both sides of filament) or a hobbed gear cut to wrap halfway around the filament. Mine uses the latter and I suspect it's the better choice.
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2021-04-22T13:33:05.840Z
You might even be able to get away with just replacing the hobbed gear in the stock extruder, but some reduction might also be needed to increase torque too.
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2021-04-22T18:08:25.763Z
I've already mounted a double hobbed gears... and actually I'm not having a problem of quality in prints (just some filaments)... how can I measure if my printer is printing the right amount of filament?
Leviand
CC BY-SA 4.0
2021-04-22T18:15:21.417Z
This should be another question/answer pair... https://letsprint3d.net/how-to-calibrate-the-extruder-steps-ender-3-5-cr-10/ will show you how to check the extrusion values for your printer.
fred_dot_u
CC BY-SA 4.0
2021-04-22T19:17:34.387Z
@Leviand: Can you show a picture of the extruder gear setup you're using or name/link the specific product if it's something commercially available?
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2021-04-22T19:35:40.790Z
@R..GitHubSTOPHELPINGICE I've added an image in the question, the name is "3Dman 11 Dual Gear Extruder ". I've never done a calibration before, I will give a try!!!
Leviand
CC BY-SA 4.0
2021-04-22T11:35:20.707Z
2021-04-22T19:25:27.170Z
2021-04-22T19:25:27.170Z
R.. GitHub STOP HELPING ICE
<p>I've recently switched to PETG , and I'm using Cura as slicer and Ender 3 as printer.</p>
<p>I'm printing a model which Cura declares to be <strong>35 g</strong>, but if I weigh the printed model it weighs <strong>23 g</strong>.</p>
<p>I'm printing with just 1 line of skirt, so its weight is negligible on total weight.
I've replaced the stock plastic extruder with a double gears metal extruder (3Dman 11 Dual Gear Extruder ).</p>
<p><a href="https://i.sstatic.net/22V5v.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/22V5v.jpg" alt="enter image description here" /></a></p>
<p>I've also replaced the stock springs with metals ones.</p>
<p>I'm not having a quality problem, just I want to understand if this difference is caused by a bad configuration that could be improved.</p>
<p>Which are the corrections/checks that I need to do in my setup (both printer and Cura) for fixing this difference?</p>

CC BY-SA 4.0
2021-04-22T19:20:21.910Z
In case Cura is being stupid, look at the final E-axis value in the output gcode file to see how much material it's attempting to extrude. Multiplying it by 2.4 ((1.75/2)² × pi) will give the volume of material in mm³ which you can then multiply by the expected density.
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2021-04-22T19:20:47.757Z
Also: Is it possible there's priming-line, skirt, brim, raft, or support material you're not counting?
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2021-04-22T19:23:28.073Z
Good guess, but I'm printing just 1 line of Skirt, just for clearing the nozzle... 
totally negligible, I guess. Btw I'm adding this information to the question, might be useful.

I'm looking for the value you are referring to tomorrow and I'll post you back, thanks
Leviand
<creality-ender-3><ultimaker-cura><petg>
Difference in weight from Cura to printed model
Leviand
# Difference in weight from Cura to printed model

(Asked by: username_0 on 2021-04-22)

I've recently switched to PETG , and I'm using Cura as slicer and Ender 3 as printer.

I'm printing a model which Cura declares to be **35 g**, but if I weigh the printed model it weighs **23 g**.

I'm printing with just 1 line of skirt, so its weight is negligible on total weight.
I've replaced the stock plastic extruder with a double gears metal extruder (3Dman 11 Dual Gear Extruder ).

[![enter image description here](https://i.sstatic.net/22V5v.jpg)](https://i.sstatic.net/22V5v.jpg)

I've also replaced the stock springs with metals ones.

I'm not having a quality problem, just I want to understand if this difference is caused by a bad configuration that could be improved.

Which are the corrections/checks that I need to do in my setup (both printer and Cura) for fixing this difference?

**Tags:** creality-ender-3, ultimaker-cura, petg

> **Comments:**
> **username_1**: In case Cura is being stupid, look at the final E-axis value in the output gcode file to see how much material it's attempting to extrude. Multiplying it by 2.4 ((1.75/2)² × pi) will give the volume of material in mm³ which you can then multiply by the expected density.  
> **username_1**: Also: Is it possible there's priming-line, skirt, brim, raft, or support material you're not counting?  
> **username_0**: Good guess, but I'm printing just 1 line of Skirt, just for clearing the nozzle...  totally negligible, I guess. Btw I'm adding this information to the question, might be useful.  I'm looking for the value you are referring to tomorrow and I'll post you back, thanks  

---

## 2 answers

### Answer by username_2 on 2021-04-22. Score: 3

The density of the filament can be specified in the material model of the filament in Cura (Preferences -> Configure Cura... -> Materials and click on the material/filament you are using to slice your model for PETG), look at the value behind *Density*, the PETG filament I use is using 1.28 g/cm³ ([PETG Economy Black -> Specification >](https://colorfabb.com/petg-economy-black)).

[![Cura materials window](https://i.sstatic.net/vy283.png "Cura materials window")](https://i.sstatic.net/vy283.png "Cura materials window")

This field is user editable, so you can change it to your needs. Cura calculates the weight based on the deposited volume.

> **Comments:**
> **username_0**: Thanks for your answer: I've setted the density to 1.27 , but I'm now getting 37gr, which leads to a bigger difference. Is there any other possible problem?  
> **username_3**: This setting is used to allow the viewer to determine expected filament use for the print. As you've already discovered, an inaccurate figure will present a disparity between the displayed value and the weight of the print. Changing the numbers will only provide for a value difference, not an operational difference. The other answer (currently) is not likely to be correct, unless you are having model quality problems.  
> **username_0**: @username_3 actually I'm not having a quality problem: I'm only trying to understand if my printer is printing correctly or if something is not right setted. This difference has raised a warning in my mind...  
> **username_3**: I didn't think you were having a problem with quality, as that would have taken priority, in my opinion. The answer referencing underextrusion appears to be off-base for that reason. If you use trial and error to enter a weight value in the settings, until you get something that matches closely enough, you'll have done no harm.  

---

### Answer by username_1 on 2021-04-22. Score: 2

Likely underextrusion. The Ender 3's extruder is particularly bad at PETG and slips a lot unless you go really slow, like 3 mm³/s (about 40 mm/s at 0.2 mm layers and 0.4 mm line width) or lower.

For a long time I thought this was a limitation of the material, at least without a really powerful hotend, and wondered why anyone liked it. But after replacing the extruder on my Ender 3 with one that grips the filament much better (among other differences) I can extrude at several times that rate with no extrusion issues.

My extruder has a lot of differences from the stock Creality one that might be making a difference. It's (remote) direct drive, has a cut-out hobbed gear that wraps partly around the filament tensioned rigidly rather than with a spring, and has net 10:1 reduction gearing. I suspect the hobbed gear configuration makes the biggest different to increased PETG printing capability but I'm not sure. Here's a picture of what I'm talking about

![hobbed filament gears](https://i.sstatic.net/NxSQx.jpg)

> **Comments:**
> **username_0**: Actually I'm printing at 40mm/s , because that's the only way I've found to be able to work with petg and ender 3... and the first layer I'm lowering it to 10mm/s ... Which extruder are you suggesting to upgrade to?  
> **username_1**: I'm not making a particular recommendation because there are lots of factors to weight choosing what you want and product recommendations are off topic for this site. I have a flex3drive remote direct drive but it's some work getting it setup well. Mainly for this specific problem I suspect you need either double hobbed gears (both sides of filament) or a hobbed gear cut to wrap halfway around the filament. Mine uses the latter and I suspect it's the better choice.  
> **username_1**: You might even be able to get away with just replacing the hobbed gear in the stock extruder, but some reduction might also be needed to increase torque too.  
> **username_0**: I've already mounted a double hobbed gears... and actually I'm not having a problem of quality in prints (just some filaments)... how can I measure if my printer is printing the right amount of filament?  
> **username_3**: This should be another question/answer pair... https://letsprint3d.net/how-to-calibrate-the-extruder-steps-ender-3-5-cr-10/ will show you how to check the extrusion values for your printer.  
> **username_1**: @username_0: Can you show a picture of the extruder gear setup you're using or name/link the specific product if it's something commercially available?  
> **username_0**: @username_1 I've added an image in the question, the name is "3Dman 11 Dual Gear Extruder ". I've never done a calibration before, I will give a try!!!  

---

