3D Printer Stops Extruding Mid Print: Here’s What To Do

There is nothing more frustrating than starting a project only to see the extruder stopping mid-print. While the issue is annoying, the solution is often simple.

The main reasons why your 3D printer stops extruding mid-print include filament run out, an overheated extruder motor driver, a clogged nozzle, or incorrect calibration. Problems could also arise if the filament is grinding inside the extruder. However, all these problems have quick, straightforward solutions. 

5 Reasons Why 3D Printer Stops Extruding Mid Print

There are four main reasons why your printer stops extruding mid-print, and a fifth, not so obvious one.

Finding the potential culprit is the first step to fixing the problem.

1. Out of Filament

The most obvious reason why a 3D printer stops extruding mid-print is an empty filament spool. 

This can happen if you forget to check the amount of filament on the spool before hitting print, or due to an incorrect calculation of the amount of filament necessary for your project. 

Most printers will pause printing when the filament runs out, unload the spool, and prompt you to load a new one. 

The steps can vary depending on the printer and slicer you use.

2. Printing Settings 

If you’re printing a model that somebody else has sliced and the printer stops and unloads the filament mid-print, it might be worth it to check the model colors and print settings in your slicing software or within the G-Code. 

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That’s because most slicers – and particularly Cura – allow changing the filament mid-print so that you can continue printing with a new color or even a different material, should that be your intention.

If the model has two or more colors and somebody else sliced it for you, the printer might stop mid-print due to the G-Code assisted switch.

In this case, if you want to use the same filament from start to finish, you have to slice the model again or alter the G-Code to prevent the automatic spool unloading.

3. Grinding Filament 

Grinding filament is a common problem among beginners that mostly happens due to incorrect calibration settings. 

A too fast printing speed, too aggressive retraction, low feed rate, or low temperature can all lead to grinding, which basically refers to filament being sandwiched between the drive gear and its bearing.

The drive gear’s teeth keep grinding on the same spot of the filament, wearing down.

Due to excessive grinding, that portion of filament becomes too thin and the gear can’t grip on it properly. Hence, feeding is halted and the machine will stop extruding mid-print.

4. Clogged Extruder 

Clogs in the hot end are another cause of paused extrusion. A thing to keep in mind, though, is that clogs can happen anywhere inside the hot end, not only in the nozzle.

For instance, the problem could be in your Bowden tube. 

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This is why you should inspect the entire extrusion system if the printer keeps pausing mid-print even if you’ve cleaned or changed the nozzle.

5. Overheat Extruder Motor Driver

To extrude material, the printer uses an extruder motor driver that spins back and forth, gripping onto the filament and pushing it forward.

This motor driver works very hard and could overheat if you keep the printer in a too hot environment. 

Overheating could also happen due to incorrect hot end settings, or due to malfunctions and system failure.

Regardless of what causes overheating, the motor driver features a thermal cutoff that automatically stops the printer to prevent component damage and minimize the fire hazard.

How To Fix Mid-Print Extrusion Stops

Now that you know what can cause extrusion issues, it’s time to find out how to fix these potential issues.

Follow the steps below to get rid of the problem.

1. Check The Filament Before Printing

The first step to preventing paused extrusion mid-print is to check the amount of filament on the spool before starting the process. 

How much filament you need largely depends on the print size and infill settings. Generally, a kilogram of filament – the standard size of most spools – is enough for printing around 100 miniatures with a low infill pattern.

On average, small to mid-sized prints require about 50 grams of filament, meaning that you could technically get around 20 objects out of one spool.

However, it is a good idea to load a new spool if there is little filament left on the old one.

2. Check Printer Parameters in Slicer 

As mentioned, the printer could sometimes stop extruding mid-print due to information received from the firmware or your slicing software. 

This is often the case when printing multicolored objects, if you’ve opted for a G-Code assisted spool switch.

After the printer extrudes the last row of the first color, the firmware pauses the operation and homes the arm to position 0. It also unloads the spool automatically and prompts you to load the new filament.

If you’ve sliced the object yourself, you’re likely aware of the switch.

However, if you want to print something that somebody else sliced before you, it might be worth checking the printing parameters in the slicing software or directly in the G-Code.

Reslicing might be necessary if you want to print an initially multicolored object in only one color.

3. Check Printing Temperature 

Grinding can strip off a lot of filament when the thread passes through the motor driver gear, and this usually happens due to a too low printing temperature. 

The low temperature prevents the proper melting of the filament.

The rigid thread is more likely to get damaged when coming in contact with the gear’s teeth, and it will eventually shed off so much plastic that the gear won’t be able to feed anything. 

A low temperature also slows down extrusion, increasing the risk of grinding. 

To prevent issues, you should check the recommended printing temperature on the spool label before beginning.

Also, keep in mind that the temperature might vary slightly from printer to printer, so adjust in small increments (5°C) at a time to find the sweet spot for your system.

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The table below shows the recommended hot end temperatures for various filament types: 

Filament TypeHot End Temperature Range
PLA215°C - 235°C
ABS230°C - 240°C
PETG230°C - 250°C
TPU195°C - 230°C

4. Check Printing Speed & Feed Rate

Beyond temperature, the printing speed and feed rate can also lead to grinding and extrusion issues.

Like the temperature, you’re likely dealing with a too low speed or feed. Check the settings in your slicer or firmware and adjust the speed based on the type of filament you’re using. A low volumetric extrusion could also be the culprit.

Volumetric extrusion issues are almost always linked to wrong filament parameters (such as type and thread diameter) inserted into the slicer or firmware.

As far as printing speed goes, PLA and ABS generally do well at a speed of around 60 mm/second. PETG requires between 60 and 100 mm/second, but TPU should be printed really slow, at a speed between 15 and 20 mm/second.

5. Calibrate Retraction 

Together with the print speed, feed rate, and temperature, an aggressive retraction could also lead to grinding and filament stripping.

That’s because the machine retracts a too long length of filament, and the same portion of the thread can pass through the motor driver gear several times. 

If you’ve adjusted the print speed, feed rate, and temperature, reduce retraction by about 50%.

From here, you can decrease or increase retraction in small increments until you’ve got a decent amount to prevent oozing while also avoiding grinding. 

6. Clean or Change the Nozzle

Using a dirty nozzle is never a good idea.

Apart from a variety of printing defects, such as blobs or zits on your 3D print, stringing, and under-extrusion, a partial clog in the nozzle can easily become a full clog due to material build-up. 

It doesn’t take a rocket scientist to figure out that extrusion won’t happen if the nozzle is completely blocked. 

Hence, to avoid problems, you should clean the nozzle each time after printing. With proper maintenance, wiping the nozzle with a damp cloth and removing excess material with a wire brush should suffice.

Alternatively, you could use the needle provided with your printer or use solvents and heat to remove stubborn clogs.

If cleaning the nozzle doesn’t do the trick or the part is too worn-out, you should replace the nozzle with a new one.

7. Change the Bowden Tube 

When thinking about clogs, most 3D printing newbies stop at the nozzle. However, blockages can happen in other parts of the extruder, too. 

Clogs in the Bowden tube are more common than you think, especially in specific printers such as the Ender 3. 

To unclog a Bowden tube, you should use the long needle provided with your printer – or any other long needle with a diameter smaller than the inner diameter of the tube.

Alternatively, you should remove this part and replace it with a new one.

8. Change Printer Location 

As mentioned, a too low temperature, printing speed, or feed rate can lead to grinding, which could cause a mid-print extrusion halt. 

Beyond printer settings, though, you should also consider the environmental conditions.

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If the printer is kept in a cold room, the low room temperature could make it hard for the machine to heat the filament properly before feeding it.

This could cause delays in extrusion or problems with the speed and retraction, which could lead to grinding.

For this reason, it is important to keep the printer in a heated room during winter. The ideal room temperature should be constant and around 77°C. 

Remember that a too hot room can also cause issues, overheating the motor driver and triggering the overheat switch off. Thus, the room shouldn’t be warmer than the temperature recommended above.

Ender 3 and Prusa Stops Extruding Halfway 

If you’ve been printing for some time and used different types of equipment, you might have noticed that two printers stop extruding halfway more than others. These brands are Ender 3 and Prusa.

Ender 3 V2 stops extruding mid-print more commonly due to clogs in the Bowden tube or other parts of the hot end.

Nozzle and full hot end replacements can fix the issue at least temporarily, but you may want to pay extra attention to the hot end maintenance if you have this printer.

On Prusa, the most likely problem is a heat creep that causes clogs. To prevent issues, you should check the extruder fan and make sure it’s set correctly. The ambient room should never go above 95°F.

If the problem occurs when the printer is in an enclosure, placing it in a cooler environment might help.

The material you’re using can also determine heat creep frequencies – this issue is more common when printing with PLA. 

On both printer types, incorrect calibration and the printer settings mentioned above could stop extrusion halfway. 

Frequently Asked Questions

Can bad filament cause under extrusion?

Yes, poor quality filament can cause under extrusion, mainly due to moisture retention and knotting. These problems can also affect quality filament that is not stored or dried correctly.

Abrasive filaments can also cause wear and tear on the hot end and other printer parts that can lead to under extrusion.

What does heat creep look like?

Heat creep is easy to detect by looking at the top layer of your print. If it’s all fuzzy and looks only half-complete, you’re likely dealing with heat creep.

Air bubbles in the extruded filament are also the result of heat creep.

Is extruder clicking bad?

Yes. Clicking sounds in the extruder are an indicator that something is wrong.

Stop the printer and investigate the cause to prevent extensive damage.

Final Thoughts

Insufficient filament, incorrect settings, filament stripping, clogs in the hot end, and overheating of the motor driver are the most common reasons why the 3D printer stops extruding mid-print. Fixing the issue is usually quick once you’ve identified the culprit, but you might have to invest in a new nozzle or hot end.

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