How to Fix 3D Printer Pausing or Freezing During Print


A 3D printer that pauses during the printing process can definitely be frustrating and can ruin the whole print. I’ve had this happen a few times so I decided to look into why this is happening and write an article to help other people.

To fix a 3D printer pausing during print, you want to ensure there aren’t mechanical issues like the extruder being clogged or a loose connection with the PTFE tube and hotend. You also want to check for heat issues that can cause clogs like heat creep, as well as connection issues with the thermistor.

There’s some more useful information that you’ll want to know so keep on reading to find out more about your 3D printer pausing during the print.

Why Does My 3D Printer Keep Pausing?

A 3D printer pausing or stopping during a print can be due to several reasons depending on your specific situation. It really comes down to narrowing what issue you are having by going through a list of checks and solutions until you find the one that works for you.

Some reasons are more common than others, but it shouldn’t be too difficult to figure out why your 3D printer keeps pausing or randomly stops.

Here is a list of reasons I could find.

Mechanical Issues

  • Bad quality filament
  • Extruder clogged
  • Filament path issues
  • PTFE tube connection with hotend loose or has a gap
  • Dirty or dusty extruder gears
  • Cooling fans not working properly
  • Filament spring tension not set correctly
  • Filament sensor error

Heat Issues

  • Heat creep
  • Enclosure too hot
  • Incorrect temperature settings

Connection Issues

  • Printing over Wi-Fi or computer connection
  • Thermistor (Bad wiring connections)
  • Power supply interruption

Slicer, Settings or STL File Issues

  • STL file resolution too high
  • Slicer not processing files properly
  • Pause command in the G-code file
  • Minimal layer time setting

How Do I Fix a 3D Printer That Keeps Pausing or Freezes?

In order to make this easier to fix, I’ll group some of these common reasons and fixes together so they are of a similar nature.

Mechanical Issues

The most common causes of a 3D printer that pauses or stops during the printing process is down to mechanical issues. This ranges from problems with the filament itself, to clogs or extrusion pathway issues, down to bad connections or cooling fan issues.

The first thing I would check is that your filament isn’t causing the problem. It can be down to bad quality filament that maybe has absorbed moisture over time, making it more prone to snapping, grinding, or just not printing very well.

Changing your spool for another fresher spool may fix the issue of your 3D printer pausing or shutting off mid-print.

Another thing you want to do is to make sure your filament flows through the extrusion pathway smoothly, rather than with resistance. If you have a long PTFE tube with many bends, it can make it harder for the filament to feed through the nozzle.

One issue I had, was that my spool holder was a little far from the extruder so it had to bend quite a bit to get through the extruder. I fixed this by simply moving the spool holder closer to the extruder and 3D printing a Filament Guide on my Ender 3.

Look out for any clogs in your extruder as this can start to build up and cause your 3D printer to stop extruding mid print or pausing during the print.

One lesser known fix that has worked for many is to ensure the PTFE tube connection with your hotend is properly secure and doesn’t have a gap between the tube and the nozzle

When you put together your hotend, a lot of people don’t actually push it all the way into the hotend, potentially causing printing issues and clogs.

Heat up your hotend, then remove the nozzle and pull the PTFE tube out. Check if there is residue inside the hotend, and if there is, remove it by pushing it out with a tool or object like a screwdriver/hex key.

Make sure to check the PTFE tube for any sticky residue at the bottom. If you find some, you want to cut the tube from the bottom, ideally with PTFE Tube Cutters from Amazon or something sharp so it cuts nicely.

You don’t want to use something that squeezes the tube like scissors.

Here’s a video by CHEP explaining this issue.

Try cleaning up any dusty or dirty areas like the extruder gears or the nozzle.

Check that your extruder spring tension is set correctly and isn’t too tight or loose. This is what grips your filament and helps it move through the nozzle during the printing process. I wrote an article called Simple Extruder Tension Guide for 3D Printing, so feel free to check that out.

Here is an extruder troubleshooting video to help out with some of these mechanical issues. He talks about the extruder spring tension and how it needs to be.

Another thing to watch out for is your filament sensor. If the switch on your filament sensor isn’t functioning properly or you have issues with the wiring, it can cause your printer to stop moving mid-print.

Either turn this off and see if it makes a difference or get a replacement if you find out this is your issue.

Mechanically check the parts of your 3D printer and make sure they are in good order. Especially the belts and idler pulley shaft. You want the printer to be able to move without any snags or unnecessary friction.

Tighten the screws around your 3D printer, especially around the extruder gear.

Check that your wires aren’t catching on anything if you find your prints are failing at the same height. Check your extruder gear for wear and replace it if they are worn out.

One user experience a misaligned idler bearing in the extruder. If that bearing is shifted, it can cause friction against the filament, preventing it from flowing easily, essentially pausing the extrusion.

As shown in the picture below, the idler bearing was misaligned due to the handle it was attached to being misaligned.

3D Printer Pauses During Print - Misaligned Idler Bearing - 3D Printerly

You may need to take your extruder apart, check it, then reassemble it.

Heat Issues

You could also experience pauses or 3D prints messing up half way during your 3D prints because of heat issues. If your heat is travelling too far up the heatsink, it could cause filament to be softening where it shouldn’t leading to clogs and jams in the printer.

You’d want to reduce your printing temperature in this case. Another few fixes for heat creep is to decrease your retraction length so it doesn’t pull soft filament back too far, increase the printing speed so it doesn’t heat the filament for too long, then make sure the heat sink is clean.

Ensure your cooling fans are working nicely to cool the right parts down because this can also contribute to heat creep.

Another less common fix that has worked for some people is to make sure their enclosure doesn’t get too hot. If you are printing with PLA, it is quite sensitive to temperature so if you use an enclosure, you should try opening up a small section of it to let some of the heat out.

Using an enclosure & temperature gets too hot, leave a gap in the enclosure so heat can escape. One user took the top off his cabinet enclosure and everything printed properly since doing so.

Connection Issues

Some users have experience connection issues with their 3D printer such as printing over Wi-Fi or a computer connection. It’s usually best to 3D print with a MicroSD card and USB connection inserted into the 3D printer with the G-code file.

You shouldn’t usually have issues printing over other connections, but there are reasons why it can cause a 3D printer to pause during printing. If you have a weak connection or your computer hibernates, it can stop sending data to the 3D printer and ruin the print.

Printing over Wi-Fi can cause issues if you have a bad connection. It could be the baud rate on the connection or the com timeout settings in a software like OctoPrint.

You may also be experiencing wiring or connection issues with thermistor or cooling fan. If the thermistor is not fitted correctly, the printer will think it’s at a lower temperature than it actually is, causing it to increase in temperature.

This can cause printing issues which lead to your 3D print failing or your 3D printer clogging then pausing.

There is a possibility that you had a power supply interruption during the printing process, but if you have the print resume function like most 3D printers, this shouldn’t be too much of an issue.

You can simply resume from the last printing point after you turn the 3D printer back on.

Slicer, Settings or STL File Issues

The next set of issues comes from the STL file itself, the slicer, or your settings.

Your STL file could have a resolution too high, causing issues since it will have a lot of short segments and movements that the printer may not be able to handle. If your file is really large, you could try exporting it to a lower resolution.

An example would be if you have an edge of a print that has very high detail and contained 20 small movements within a very small area, it would have many instructions for movements, but the printer wouldn’t be able to keep up so well.

Slicers can usually account for this and override such instances by compiling the movements, but it may still create a pause during printing.

You can reduce polygon count by using MeshLabs. One user who repaired their STL file through Netfabb (now integrated into Fusion 360) fixed an issue with a model that kept failing at a specific area.

There could be a slicer issue where it cannot properly handle a certain model. I’d try using a different slicer and seeing if your printer still pauses.

Some users experienced their 3D printer pausing during a print due to having a minimum layer time input in the slicer. If you have some really small layers, it could create pauses to satisfy the minimum layer time.

One last thing to check is that you don’t have a pause command in the G-code file. There is an instruction that can be input into files that pause it at certain layer heights so double-check you don’t have this enabled in your slicer.

How Do You Stop or Cancel a 3D Printer?

To stop a 3D printer, you simply use the control knob or the touchscreen and select the “pause print” or “stop print” option on the screen. When you click the control knob on the Ender 3, you will have the option to “pause print” by simply scrolling down on the option. The print head will move out the way.

The video below shows you what this process looks like.

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