How to Properly Tension Belts on Your 3D Printer – Ender 3 & More


There are several factors that affect 3D print quality, one of those things being your belt tension. If you aren’t sure about how to properly tension the belts on your 3D printer, this article will guide you through that process.

The best way to ensure you properly tension your 3D printer belts is to tighten it so it hasn’t got any slack and has some resistance to being pushed down. It should be around the same tension as a stretched out rubber band, but don’t tension your belts too tight because it can increase the wear on the belt.

The rest of this article will detail the best process to figure out how tight your belt tension should be, as well as other useful information regarding this topic.

A Guide on How To Properly Tension/Tighten Your 3D Printer Belts

The proper technique to adjusting your printer belt tension does vary across printer brands and styles, since many 3D printers are built differently, but there are similarities.

It’s a good idea to first figure out how your 3D printer works and how the belts are joined on the X & Y axes. For this article, I’ll be talking about how you tighten an Ender 3 belt.

The X-axis belt runs directly through the extruder, and the extruder is attached to a motor that allows it to move back and forth across the X-axis belt. Some methods which can be followed are explained below to adjust the tension of the printer belt.

Tighten Screws on X-axis: In most printers, the belt is attached to X-axis and a pulley that is further attached to a motor shaft to maintain tension in the belt.

If you look closely, you will find screws on both sides of the X-axis. Tighten these screws as it helps you in getting the right tension in the belt of the printer.

Adjust the Tensioner: To adjust the tension, you will require a hex key that comes with the printer. The remaining process is given below.

How Do You Tighten an Ender 3 Belt

  • Loosen the two nuts that hold the tensioner in place

Fix Tension on 3D Printer - Undo T-Nut Screws - 3D Printerly

  • Use the larger hex key and slide it down between the tensioner and the x-axis extrusion rail.

Fix Tension on 3D Printer - Hex Key Between Tensioner - 3D Printerly

  • You can now use this as a lever to apply force on the tensioner and keep it as far out as possible to keep the belt tight.

Fix Tension on 3D Printer - Hex Key Pressure & Tighten - 3D Printerly

  • At that moment, tighten the bolts back up on the tensioner
  • Once it is done, you can repeat the same process on the Y-axis.

Adjusting the Belt Tension at Y-Axis

Adjust the belt tension on your Y-axis works the same way as on the X-axis, but usually it doesn’t require as much tension adjustment.

Your printer belt is moved through stepper motors from one side to the other, and they don’t usually need replacing if treated right, unless it’s been years. Over time, they can stretch and break, especially if used constantly.

How to Tension Belt - Y Axis T Nut Screws - 3D Printerly

The video below shows a nice visual on tensioning an Ender 3 belt, which you can do for the Y-axis.

If you would rather choose an option that allows you to tension your belts with ease, I’d consider getting yourself the UniTak3D X-Axis Belt Tensioner from Amazon.

It fits around the end of your 3D printer on the 2020 aluminum extrusion, but instead, it has a wheel tensioner to make the job easier. It’s very easy to install and requires no assembly!

You can also get the BCZAMD Y-Axis Synchronous Belt Tensioner from Amazon to have the same functionality on the Y-axis.

How Tight Should My 3D Printer Belt Tension Be?

Your 3D printed belt should be relatively tight, so there is a good amount of resistance, but not so tight that you can barely push it down.

You don’t want to over-tighten your 3D printer belt because it can cause the belt to wear out a lot quicker than it would have otherwise. The belts on your 3D printer can be pretty tight, to the point where getting underneath it with an object is fairly difficult.

Below is a little visual on how tight the Y-axis belt is on my Ender 3. Getting the belt to this position takes a decent amount of push and that is really stretching it, so you can look towards having your belt around the same tightness.

How to Tension Belt - Y Axis Belt Tightness - 3D Printerly

You can gauge belt tension pretty well by watching a video and seeing how tight it looks and springs.

A loose belt can result in skipped layers and is very likely to decrease your print quality, so I’d advise making sure you have it at a good resistance level.

Make sure to move the X and Y axis slowly from one end to the other to make sure the belt is in good working order and not rubbing hard on the aluminum extrusion.

How Do You Know If Your 3D Printer Belt is Tight Enough?

Setting the proper tension in the belt is all about trial and error. However, there are many manual ways to find the belt’s tension and tighten it until you feel satisfied.

Some methods that are commonly followed to check the tension of the belt:

  • By touching the belt to check the tension
  • Listen to the sound of a plucked belt

By Touching the Belt to Check the Tension

This is one of the easiest ways to test the printer belt’s tension as it would only require fingers and sense to feel. If the belt is pressed with the fingers, they should be tight enough to move very little; if not, the belt must be tightened then.

Listening to the Sound of a Plucked Belt

The sound that emits from your belt after plucking it should sound like a twang, similar to a low-note guitar string. If you don’t hear any note or a lot of slack, it’s likely that your belt isn’t tight enough.

How to Fix A 3D Printer Belt Rubbing (Ender 3)

You can sometimes experience your 3D printer belt rubbing against the railing, which isn’t ideal. It can create plenty of vibrations throughout the axis, resulting in poorer surface finishes on your models.

Luckily, there are a few ways to fix this.

A solution that you can try is having the belt tightener at a downward angle, allowing the belt to get low enough to get space on the metal. This works because there is still some up and down motion after tensioning your belts.

So basically tilt your belt tensioner downwards so it runs below the lip of the railing.

Once your belt is below the part of the rail which it rubs against, you can fully tighten the two T-nut screws that hold the pulley in place.

Something that has worked for many users is using either a spacer or installing a 3D printed Belt Tensioner from Thingiverse for their 3D printers.

Another user who had the same issue of their 3D printer belt rubbing on an Ender 3 was to turn the bolt itself a quarter of a turn at a time, then testing whether it ran smoothly until the belt ran center.

One guy had some luck by replacing the thin nut on the left with two M8 washers and an M8 sprung washer. After implementing this, their belt ran perfectly fine.

Ender 3 x axis fix

Best Ender 3 Belt Upgrade/Replacement

A good Ender 3 belt replacement that you can get yourself is the Eewolf 6mm Wide GT2 Timing Belt from Amazon for a pretty good price. Many reviews talk highly of this belt for good reason.

The rubber material is a high strength synthetic rubber called Neoprene, along with glass fiber throughout. It can comfortably be used for your X-axis and Y-axis and you’re getting 5 meters of belt so you can replace it easily when needed.

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