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What To Do When a 3D Printer Doesn’t Stop Extruding

The first step to solving any extrusion issue is understanding what exactly is causing it. So, what should you do when a 3D printer doesn’t stop extruding?

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Extruding anomalies, such as under or over-extrusion, are among the most common problems of 3D printers. The first step to solving any extrusion issue is understanding what exactly is causing it. So, what should you do when a 3D printer doesn’t stop extruding?

When a 3D printer doesn’t stop extruding, check the temperature, extrusion multiplier, retraction, print speed, filament diameter, and nozzle width. Potential errors in the code or hardware issues can also cause the issue. Possible fixes include resetting and cleaning your 3D printer.

3D printer settings can’t remain identical for different filaments as this can cause extrusion issues. This article discusses the potential causes and what you can do when your 3D printer doesn’t stop extruding.

Why Your 3D Printer Won’t Stop Extruding

All 3D printers using the fused deposition modeling (FDM) technology are fundamentally the same but have several customizable settings apart from the distinct features and specs. So, you have to review all these variables at play to know why your 3D printer won’t stop extruding.

The 3D Printing Temperature Is High

A 3D printer won’t stop extruding if the printing temperature is too high for a particular filament. All 3D filaments, whether PLA, ABS, or something else, have a specific printing temperature recommended by the manufacturer. A higher heat setting will melt more filament than necessary at a given moment, making the thermoplastic ooze out of the nozzle. In turn, this leads to unwanted over-extrusion. 

Also, unusually high 3D printing temperatures can lead to stringing and blobs, both of which are symptoms of over-extrusion. Furthermore, the perfect 3D printing temperatures may vary for different qualities of the same filament, depending on additives, colors, and diameter.  

How To Fix

Use the recommended 3D printing temperature for a specific filament. Review the settings to prevent over-extrusion if your 3D printer or a particular model or material needs a slightly higher temperature. A little bit of trial and error is unavoidable, but you’ll eventually find the magic figure.  

The Extrusion Multiplier Is Inappropriate

A high extrusion multiplier may be the problem if your 3D printer won’t stop extruding. The extrusion multiplier in your 3D printer slicer software controls the flow rate of the filament. Check this setting on your slicer and the 3D printer’s control panel. Usually, the default setting is 1 or 100%, depending on the model in question.

How To Fix

You have to lower the extrusion multiplier from 1 or 100%. The solution may be anything between 99% and 90%, depending on how much over-extrusion you already have. Ideally, each 3D print profile should have a modified and suitable extrusion multiplier to prevent numerous problems.

Here’s a YouTube video tutorial showing you how to calibrate and fine-tune your 3D printer extrusion multiplier:

You’re probably aware that the slicer software and your 3D printer both determine the flow rate of a filament. The extrusion multiplier of the slicer and the flow of the 3D printer firmware that you can access and control through the LCD or control panel must complement other settings. 

Don’t change your 3D printer flow rate and the code or slicer’s extrusion multiplier at the same time to solve the over-extrusion problem. Modify one setting at a time to resolve the issue. Changing multiple settings simultaneously won’t offer a definitive solution.

The Retraction Settings Are Unsuitable

All modern FDM 3D printers have a retraction feature. The retraction setting essentially stops the extrusion process by reversing the rotation of the gear inside the hotend. This recoil effect relieves the pressure inside the hotend. Consequently, it prevents the excess filament from oozing out of the nozzle. Hence, an unsuitable retraction setting will cause a 3D printer to keep extruding. 

Contrary to a widespread misconception, 3D printers don’t retract or pull back extruded filament after the thermoplastic is already out of the nozzle. 

The retraction feature stops the extrusion for a brief moment, especially when the 3D printer hotend and nozzle have to move a distance without depositing any thermoplastic, depending on the specific elements of a given design.

How To Fix

Like the other remedies, the retraction settings also require some trial and error. 

Here’s what you have to do:

  1. Check if the retraction feature is enabled for your 3D printer. Most 3D printers have an easily accessible on/off switch.
  2. Check if the related settings are all right. Check the nozzle diameter, extrusion multiplier, and extruding filament width.
  3. Review the retraction distance, speed, and vertical lift. These settings are completely customizable on modern 3D printers.

Watch this YouTube video to calibrate the retraction settings if your 3D printer won’t stop extruding:

The Printing and Movement Speed Is Slow

Excessively high printing temperatures melt more filament than necessary at a given point. This makes it appear as if your 3D printer won’t stop extruding. Likewise, an unusually slow printing or movement speed will have the same effect. You’ll notice blobs, stringing, and other deformities in your projects.

Also, every significant setting explained in this guide is correlated. The extrusion multiplier and retraction don’t operate in isolation or are unrelated to the 3D printing and movement speed, hotend temperature, filament type & diameter, and nozzle width. That’s why you need to check each setting individually.

How To Fix

Increase the 3D printing speed or nozzle movement speed if all other settings are fine for a specific design. Otherwise, you may notice under-extrusion. Also, 3D printing speeds often vary for the base and upper layers. You should inspect all printing phases when your 3D printer won’t stop extruding.

Filament Diameter and Nozzle Width Issues

An extrusion multiplier setting for 1.75 mm (0.07 in) filament is inappropriate for 3 mm (0.12 in) filaments. If the flow rate was originally set to 1/100% for 1.75 mm (0.07 in), it must be reduced for 3 mm (0.12 in) filaments. Otherwise, your 3D printer will over-extrude. 

The same principle is relevant for the nozzle diameter. You must tweak the extrusion width too. 

How To Fix

Use dedicated 3D printing profiles for different filaments. This includes both the filament type and diameter. Ensure the nozzle size matches the filament diameter. 

Change the extrusion width depending on the selected layer height and other design elements, such as the perimeter wall thickness and infill density.

Final Thoughts

A 3D model’s code is executed by any slicer and printer’s firmware per the default or bespoke settings you have. 

You can’t transition from one filament or design to another without altering the ideal settings discussed in this guide. Else, you may have extrusion-related issues.

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About Ben

I started 3D printing since 2013 and have learned a lot since then. Because of this I want to share my knowledge of what I have learned in the past years with the community. Currently I own 2 Bambulab X1 Carbon, Prusa SL1S and a Prusa MK3S+. Hope you learn something from my blog after my years of experience in 3D printing.