Setting Nozzle Size and Line Width in Cura – Detailed Guide

As correctly setting the nozzle size allows Cura to load the default profile for the particular nozzle you’re using, which ensures that the majority of the print settings are automatically adjusted correctly, it’s the very first step that you will need to take when setting a Cura profile up for the new nozzle you have installed on your 3D printer.

In this guide, we will take you through the process of configuring the nozzle size & line width values in Cura and explain how you can calculate the optimal line width values for the nozzle size you’re using.

How to Set the Nozzle Size Value in Cura?

To set the nozzle size value in Cura, the first step you will need to take is to switch to the Prepare tab by clicking the Prepare button, which you can find on the top-middle part of the Cura window.

cura prepare tab


Next, click the tab located at the top-middle portion of the Cura window where you can see the filament type and nozzle size information (right below the Prepare, Preview, and Monitor tabs), which will bring up the menu where you can choose the nozzle size appear.

cura nozzle size material menu


Finally, click on the Nozzle Size dropdown, and choose the nozzle size of your choice, which will change the active nozzle size and get Cura to load the corresponding version of the default profile you already had selected before changing the nozzle size or modify the custom profile you’ve been using to make it compatible with the new nozzle size by changing the line width.

How to Set the Line Width Value in Cura?

To set the line width value (a part of the Quality settings) in Cura, you need to be on the Prepare or the Preview tab, which you can navigate by clicking the corresponding buttons on the top-middle part of the Cura window.

cura prepare tab


Next, click the tab on the top-right corner of the Cura window to bring up the Print Settings menu. Additionally, if you see the Custom button on the bottom-right side of the Print Settings menu, click it to switch from Recommended mode to Custom mode, where you can find all the settings.

cura print settings menu example


Once you can see the Print Settings menu, type “line width” into the search input to make the Line Width setting and the related parameters visible on the screen.

cura finding line width setting


Finally, enter the line width value of your choice into the Line Width input box, which will prompt Cura to automatically use the new line width value you have inputted for the G-code files you create with Cura from then on until you change it again.

cura changing line width


Calculating the Optimal Line Width Value Based on Nozzle Size

As the optimal line width value entirely depends on the size of the nozzle you’re using, you can utilize a commonly-used formula that allows you to conveniently calculate the range of line width values that will work with the particular nozzle attached to your 3D printer, which will effectively ensure that you don’t come across any issues regarding the line width value.

When you use a line width value that’s way too low for the size of the nozzle you’re using, the primary problem you will experience is under-extrusion, as the material won’t flow out of the nozzle quickly enough to be able to create even lines consistently, and the unevenness of the lines will eventually lead to the appearance of gaps between them.

Similarly, if the line width value you’re using is way too high, you will come across the under-extrusion problem once again, but this time, it will be due to your 3D printer trying to extrude more material that can actually pass through the nozzle, which will naturally lead to a scenario where the actual amount of extruded material to be less than what your 3D printer thinks.

The recommended formula that you should use to ensure neither of the cases we have gone through above takes place is 60% to 150% of the nozzle size, which, as an example, would give us a range of 0.24 mm to 0.6 mm for a standard 0.4 mm nozzle as viable line width values.

While you’ll see benefits such as increased strength and a smoother top surface when using a line width value that falls toward the lower end of the range we have mentioned, the amount of time it takes for your 3D printer to complete the print will also increase (unless you increase the print speed, which will compensate for the loss in flow rate, but can introduce mechanics-related problems based on your 3D printer’s hardware), as you will effectively be reducing how quickly the filament flows out.

On the other hand, when you use higher line width values, you will reduce the time it takes for your 3D printer to complete the print by increasing the filament flow, but at the expense of losing some strength and top surface quality, which effectively means that you should be adjusting your line width value on a case-by-case basis, as you will most likely come across both scenarios of time efficiency becoming necessary, and strength being more critical for the success of the print depending on what you’re printing.

Before we wrap up, one last thing we would like to mention about adjusting your line width value is that it directly impacts the volumetric flow rate (the amount of material that your 3D printer extrudes per second), and while this isn’t a subject that we will go into detail about in this particular article, reducing the print speed will often be a good idea whenever you’re increasing the line width (or layer height) to ensure that you aren’t pushing the volumetric flow rate to a point where your 3D printer cannot handle, as this would also result in under-extrusion.

Conclusion

While setting the nozzle size value in Cura won’t take more than a few seconds of your time at most once you know where to look, the fact that the dropdown menu isn’t located within the print settings section along with the rest of the parameters can make things a bit confusing at first, and lead you to believe that there’s no nozzle size setting in Cura.

On the other hand, when it comes to line width, you can find the setting in the print settings menu as usual, and while Cura automatically sets the line width to an appropriate value once you change the nozzle size, there’s room for customization on that front based on the purpose of the part you’re printing.