Simple Extruder Tension Guide for 3D Printing – A How-to

Extruders are a very important part of your 3D printer and getting prints to look great, but learning the right extruder tension can be confusing at first. I decided to write an article to help people learn about this aspect of your 3D printer so you can get those high-quality prints you’ve been looking for.

Keep on reading through this article to learn about extruder tension and what to do if your 3D printer has too much tension.

What Is Extruder Tension in 3D Printing?

Extruder tension in 3D printing is how tightly or loosely the extruder gear is gripping your filament. If your extruder tension is too tight, the filament will get ground or chewed by the extruder, and if it’s too loose, the filament simply won’t be pushed through to the hot end, leading to under extrusion.

Extruder tension, otherwise known as idler tension is a fairly overlooked parameter that many 3D printer users ignore until they start experiencing issues like filament skipping, under extrusion, and low-quality prints.

Most 3D printers have an extruder gear or two located somewhere on the body of the extruder. The gears or screws make it possible to adjust the extruder tension and ensure the component’s optimal performance.

Many people who experience extruder tensions issues report that their 3D printer arrived from the factory with a loose idler screw or screws, depending on the printer.

The adjustment screws can also get loose over time, so it’s a good idea to keep checking up on this important parameter occasionally so you don’t run into errors in your prints.

Having the right extruder idler tension in your 3D printer makes a significant difference in your prints, so let’s get into how you can adjust it perfectly on a 3D printer.

How Do You Adjust the Extruder Tension on a 3D Printer?

To adjust the extrusion tension, you will need to first loosen the idler screw and load the filament so it doesn’t move forward on its own. Then, you will begin tightening the screw until your filament has been gripped just enough by the extruder to push through. Trial and error will bring the best results.

Fortunately, the extruder gear tension adjustment is a fairly simple process that you can perfect with trial and error. Overtightened idler screws push the filament irregularly, so we definitely can’t have that.

It also depends on what filament you’re using to 3D print. PLA is generally more sensitive to extruder gear tension as compared to harder filaments like ABS and Nylon, so I recommend you use PLA to adjust the extruder tension for the best results.

Taking the Prusa i3 MK2S as an example, let’s break down the process into easy-to-follow steps to help you adjust the extruder tension effectively.

Step 1. Loosen the tension spring so the filament doesn’t move through on its own and there’s no resistance feeding the filament.

Step 2. Pre-heat your extruder nozzle to get it to optimal functioning.

Step 3. Choose the “Load Filament” option from the LCD panel of the Prusa i3 MK2S.

Step 4. The filament shouldn’t be pushing through because the tension spring is too loose. During this, carefully tighten the spring until the extruder gear catches the filament and starts extruding it.

• Prusa recommends that the length of the compressed tension spring should be 13mm when tightened, so trial and error in that range should give you the best extruder tension.

That’s it! That’s how you get the perfect extruder tension on your Prusa i3 MK2S. If you’re more of a visual learner, the following video should take you through the process comfortably.

With all that being said and done, the extruder tension adjustment on a Creality Ender 3 is a bit different from the method discussed above.

I’ve researched and found out that all Creality printers made after 2020 come with an adjustment screw that you can simply tighten or loose to easily adjust the extruder tension, similar to the process above.

This goes for the Ender 5, Ender 3 V2, Ender 3, and the rest of the lot. However, for all those units manufactured before 2020, the process is a bit different but still easy.

To adjust the extruder tension on an Ender 3, you can 3D print spacers and simply insert them at the end of your tension spring.

3D printable spacers can be downloaded for free from Dropbox. They come in either 1mm or 2mm, so choose whatever suits you better.

You can also download this Ender 3 Extruder Spring Tension Spacer Fix from Thingiverse.

The image below illustrates how the spacers work. Again, trial and error is highly advised here, so you can insert as many spacers as you need to achieve optimal extruder tension.

The following video by Tomb of 3D Printer Horrors explains the whole process, so check that out for a visual example.

How Tight Should Your Extruder Be?

Your extruder’s tightness should be at a point where it doesn’t compress or put too much pressure on the filament and doesn’t slip either.  Trial and error with test prints will help you calibrate your extruder just right. You don’t want a spring that’s barely pushing the idler either as it won’t extruder properly.

You don’t want to overtighten your extruder since it can cause the extruder motor to work excessively and start grinding the filament. That, in turn, can cause divots to form on your material.

Many 3D printing experts write that your extruder’s tightness can also sometimes depend on the filament you’re using.

One experienced Nylon filament user says that the popular Taulman 618 Nylon filament requires extra tightness to work perfectly, so you should really take out the time to experiment with extruder tension and see what works the best for you.

However, this doesn’t necessitate that you will have to go through this tedious process each time you print with a different filament.

Once you’ve calibrated the extruder tension, there’s no need to do it again for different filaments unless you move your 3D printer around or haven’t checked the extruder tension for many months.

As long as your prints are coming out okay, then your extruder tension is probably fine after that. Re-checking your extruder tension can be good for ensuring your printer is working optimally, to give the best details and quality in your models.

One person, in his experience, said that if the extruder gear is too tight, it will have the “same” detrimental effects as when it’s too loose, so it’s best that you hang somewhere in the balance when it comes to the perfect extruder tension adjustment.

Pro Tip: Some filaments may require different levels of tightness to work optimally. For flexible filaments, I recommend loosening the extruder gear a bit more than usual for the best results.

What To Do If Your 3D Printer Has Too Much Tension – Ender 3 & More

If your 3D printer has too much tension, you can loosen the extruder gear so the filament doesn’t under extrude. Changing the spring can work well if it’s too strong. You can also replace your current extruder with a BMG extruder or a Titan extruder for easy extruder tension calibration. 

The Bondtech BMG Extruder on Amazon is a premium and top-rated product that boasts a 4.5/5.0 overall rating at the time of writing with 79% of the people who bought it leaving a 5-star review lauded with praise.

It costs somewhere around $90, so definitely a bit pricey option for you to choose as your 3D printer extruder. Rest assured, however, since the BMG extruder is lightweight and uses Dual-Drive technology for hassle-free filament feeding.

Customers currently using it say that its machined parts are exceedingly defined, way better than what they were using before. In addition, the teeth in the gears are sharper and less curved at the tips, so filament loading is nothing short of a breeze.

People say that they were able to print fast with smooth, consistent extrusions without any grinding with the BMG extruder, which is a huge plus point. It’s compatible with most 3D printers, like the Ender 3 (Pro/V2), Ender 5, Artillery Sidewinder X1, and more.

One of this extruder’s highly admired features is effortless tension adjustment. You can calibrate the extruder tension of BMG by using its built-in thumbscrew and spring mechanism without having to use any additional tools.

As we know by now, extruder tension is something you need to be calibrated right, but not every extruder out there can be as painlessly calibrated as the BMG extruder by using its easy-access thumbscrew.

Another cheaper option is the TEVO Titan Extruder on Amazon that costs about $30 and comes with a NEMA 17 stepper motor. There are other packages to buy as well that would give you either a V6 Direct Hotend or a Volcano Bowden Hotend.

People who bought it say that their prints look better than ever with the Titan Extruder. The value for money proposition is awesome when you factor in the price of this product.

You also get all of the relevant tools you would want when buying this product. The manufacturer says that the Titan Extruder has gone through 200 hours of real machine testing before being sold publicly, so it’s a tried and tested unit.

The TEVO Titan Extruder’s tension can be adjusted by rotating the single screw below the extruder body either clockwise, which would decrease the tension, or counterclockwise, which would increase the tension.

You would then implement trial and error to see what level of adjustment gets you the perfect extruder tension. The single grub screw makes it much easier to calibrate the extruder as compared to the stock Ender 3 extruder.

The following video is a great explanation of how you can adjust the TEVO Titan extruder without breaking a sweat.