It can be quite common to run out of filament during a print and many users wonder how to properly change filament without ruining the whole print and having to start it over.

To change filament during print you can do a manual filament swap, which requires pausing the print and changing the filament by hand or modifying the G-code file so that the printer will pause automatically. You can also try doing a manual swap without pausing but it can be a bit more risky.

Keep reading for more information on how to change filament during print.

How to Change Filament Mid Print/During Print

These are the main methods to change filament during print:

1. Manual filament swap
2. Manual swap without pause
3. Modifying G-code file

1. Manual Filament Swap

The most popular way to change filament mid-print is by doing a manual filament swap by pausing the print and changing filament.

First you’ll need to pause the print by using your printer’s menu. On the Ender 3 you can easily find the “Pause Print” option after pressing the main button that controls the LCD screen.

Then just gently pull the filament out of the extruder. You’ll have to use the lever on the extruder to release the filament, allowing you to pull it out. It’s a good idea to trim the end of the new filament at a slight angle to make it easier to insert next time.

After doing that, carefully feed the new filament through the extruder, making sure it reaches the nozzle and is fits nicely.

Then just hit the “Resume Print” option in the printer’s menu and the printer will continue running your print when it reaches back to printing temperature.

Be careful not to accidentally move one of the axis by hand, as stated by one user. He said that pushing the gantry only 0.2mm down can be enough to ruin the entire print.

He uses a unique method of adding a T-nut to secure the Z-axis, so you can’t push it down by accident. Another user mentioned that having dual Z-axis leadscrews helps to prevent this issue.

If your printer has a filament runout sensor, just make sure it is turned on in your printer’s settings. When the filament runs out, the sensor should automatically pause the print for you. Then just follow the same steps as the other printers.

One owner of a Prusa MK3S stated that changing filament during print can be quite easy as the printer sensors work really well and will detect when you run out of filament and pause the print automatically.

Another user stated that pausing the print and doing a manual filament swap always worked for him to change filament mid-print.

He recommends doing the change quick and said that there may be a little blob on the print from pushing in new filament but other than that it works well. 

Check out the video below for detailed instructions on how to change filament mid-print.

2. Manual Swap Without Pause

Another method to change filament during print is by doing a manual swap but without pausing the print. This method can be helpful to people who don’t want to pause their print but may be running out of filament in the printer.

Before you do the filament change, get the new filament ready by cutting the end at a slight angle. This will make it easier to put into the printer.

Keep a close eye for when the filament is ending and its last bit is about halfway through the Bowden tube. Then just slowly feed the new filament and make sure it is right up against the old one.

You should check on the print for a few more layers to make sure everything is going well.

Just remember, changing filament without a pause button is a bit riskier, so be ready to start over if things go wrong. It’s a good idea to practice on smaller prints before attempting this on bigger, more important ones.

One user recommends this method to change filament during print as he prefers than pausing the print even if it can be a bit frantic.

Another user stated that pausing the print is usually better as this method requires you to have the right timing when making the filament change.

Some users also suggest slowing the print speed down when doing the filament change without pausing so you have a longer time to change it. After feeding the new filament in, you can turn the speed back to what it was.

3. Modifying G-Code File

Modifying the G-Code file can also be a method to change filament in mid-print. That’s because you can modify the G-code file in Cura so that the print will pause at a certain point or specific layer.

To do that, first, open your 3D model in Cura and make sure it’s the right size and in the right place. Then, find the layer where you want to change the filament and take note of its height.

Now, in Cura, go to the “Extensions” menu, click on “Post-Processing,” and choose “Modify G-Code.” Turn on the “Pause at height” option and enter the height you noted earlier.

Save the modified G-code file and load it onto your printer. Start the print, and when it reaches the designated height, it should automatically pause. 

Now you just need to follow the steps detailed in the first section of this article to change the filament, and then resume the print using your printer’s controls.

One user stated that he always uses Cura to change filament during print. He suggests setting the disarm timeout to 1800s (maximum) so the steppers will hold their position for 30 minutes.

That will help you avoid accidentally moving the gantry when feeding new filament. There are more settings that can be tweaked to perfect the change of filament mid-print but you’ll need to experiment with it, other users have stated.

Check out the video below for detailed instructions on how to change filament during print using Cura.