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Broken Filament

· 4 min read
Pranav G.
Pranav G.

Broken Filament​

What Is It?​

The filament is a relatively fine plastic thread, which can break easily under certain conditions. If your filament breaks mid-way during a print, it will cause a print failure leading to a loss of print time and effort.

Filament usually breaks due to poor quality control, high humidity, or extreme tension in the filament path. These conditions are essential to consider if you're planning to print large-sized objects or want to use your printer for batch 3D printing.

What to Check?​

  • Filament Spool and Quality
  • Relative Humidity
  • Filament feed to the extruder

How to Fix It?​

Get a New Filament Spool​

If you're regularly experiencing filament breaks during a printing cycle, it's better to reload a new filament. The previous filament roll might be of inferior quality, and it's easy to replace the spool and inform the filament manufacturer about the issue.

Otherwise, if everything's right with the filament, you can weld the two parts of the broken filament using a heat source and a filament splicer. 3D PrintScape has a detailed guide on filament welding, which can be helpful for this solution.

Use a Filament Enclosure/ Dry Box​

PLA, ABS, PETG, and Nylon are highly hygroscopic filaments; i.e., These materials tend to absorb moisture quickly. It makes the filament brittle, causing it to break easily during printing. Moreover, a wet filament will lead to bubbles on your print's surface and reduce the layer adhesion of your 3D prints.

A filament dry box ensures that the filament spool is isolated from the rest of your environment. It helps to manage the relative humidity of the filament and prevent any dust and dirt particles from contaminating the filament roll. You can use a food dehydrator as a quick remedy, but it's not developed for drying the filament and might not give satisfactory results.

Use a Filament Guide​

3D printers like Ender 3 and the CR-10 have a steep filament path from the top to the extruder. As a result, the filament is in high tension and sharply enters the extruder, which might cause the filament to break due to the extruder's constant pull and push motion.

Many users use a filament guide to guide the filament into the extruder smoothly. It's easy to print and ensures minimal tension on the filament roll. Alternatively, you can position the filament spool so that the material enters the extruder in a straight path without any tension.

What Is It?​

The thickness of each perimeter or outline and the layer height of your 3D print directly correspond to the printer's nozzle size. Using a standard 0.4 mm nozzle, you can effectively print layers between 0.12 - 0.28 mm in height. Similarly, the line width for a 0.4 mm nozzle is limited between 0.3 - 0.8 mm thickness. These limits indicate the resolution of an FDM 3D printer.

If your model has fine lines that are less than 0.3 mm, the slicer will not recognize it as part of the model. As a result, the gcode file will not have details regarding these parts, and the final print will miss out on the intricate details in your design.

What to Check?​

  • Nozzle size
  • Slicer settings
  • Print Geometry

How to Fix It?​

Use a smaller nozzle size​

A smaller nozzle size, such as 0.2 mm or 0.3 mm, will help you to print lines with less width and low layer heights. You can technically print details in your print that have a line thickness of 0.1 mm. It's highly recommended to use a smaller nozzle to print aesthetic models and designs, which contain lots of fine details.

But, with a small nozzle size, the chances of nozzle clogs increase, as any impurity in the filament or dirt particle can easily block the tiny nozzle exit. You'll also need to lower the print speed and the filament flow rate to facilitate smooth filament flow from the nozzle's small orifice.

Slicer Settings​

Slicer settings play a crucial role in printing the fine details of your models. You need to set a lower layer height and line width and enable thin line support if your slicer supports it. In Cura and PrusaSlicer, you have the option to enable support for thin walls. Whereas, Simplify3D supports printing single extrusion walls, essentially allowing you to print fine details.

Improve the Print Geometry​

Smaller nozzle sizes have several caveats linked with them. To avoid potential issues such as nozzle clogs, under extrusion, or hot end blobs, the best solution is to increase the line thickness in your design slightly.