7 Ways How to Fix 3D Printer Belt Slipping

Several factors contribute to making 3D print quality good or bad, one such thing is the properly operating 3D printer belts. 3D printer belt slipping is an issue faced by many users and this article has some tips and tricks that can help you out.

To fix your 3D printer belt slipping, tighten the belts or any loose screws. Ensure stepper motors, pulleys, and belts are in good condition. Printing slower with less jerk and acceleration settings, supplying the correct drive motor current, and proper cooling can also prevent this issue. 

This is just the basic answer, the article will guide you through the process of how things should be done.

How to Fix 3D Printer Belt Slipping

Here is how to fix the 3D printer belt slipping:

1. Properly Tighten the 3D Printer Belt
2. Decrease the Jerk, Acceleration, & Printing Speed
3. Properly Tighten Any Loose Screws 
4. Install a Cooling Fan or HeatSink
5. Check Pulley for Any Damages
6. Ensure Correct Motor Driver Current
7. Replace the Damaged Belt/Bearing

1. Properly Tighten Your 3D Printer Belt

The first step to fix the 3D printer belt slipping is to make sure your belt is properly tensioned, neither too loose nor too tight. Loose belt(s) can slip but belts that are too tight can wear quickly and cause issues.

Properly tightening the belts ensures sufficient tension to grip the pulleys. This prevents slipping while improving print accuracy and overall performance as well. A belt having tension like a stretched rubber band is considered ideal for 3D printing.

One user said that you can check if the belt is loose, too tight, or worn out by moving the axis while the stepper motors are off. If you feel too much resistance, the belt needs to be tensioned or completely replaced. 

Here is a short yet comprehensive video on tensioning the Ender 3 belt using just the hex keys.

There might be slight differences depending on the brand, type, style, and belt axis of your specific 3D printer but the core procedure will mostly be the same.

Some users recommended buying a belt tensioner such as the UniTak3D Upgrade X-Axis Belt Tensioner from Amazon, to accurately tighten the belt. 

You may also try a belt tensioner like the Ender 3 Belt Tensioner by MakeChetti from Thingiverse to make things easy and quick. 

Modern 3D printers usually have belt tensioners already attached to the X and Y axis.

2. Decrease the Jerk, Acceleration, & Printing Speed

Another good way to fix the 3D printer belt slipping is by reducing the Print Speed, Print Acceleration, and Print Jerk under the “Speed” settings in Cura.

Higher settings can cause sudden movements and speed changes leading to belt slipping more often. 

Reducing the jerk, acceleration, and printing speed helps with a controlled and strain-less movement of the belt and offers a better grip on the pulleys, reducing the 3D printer belt from slipping.

To find the optimal settings, it’s better to decrease these settings with small increments until you achieve the best results.

One user resolved the issue by reducing the print speed from Cura’s default 50mm/s to 45mm/s, which effectively stopped the slipping. Reducing the travel speed may also help.

3. Properly Tighten Any Loose Screws & Nuts

One efficient way to fix the 3D printer belt slipping is to make sure that the grub screws on the pulleys and motors are tightened perfectly.

Tightening the screws ensures better grip and secured movement by keeping the belt on the pulleys.

On the Ender 3, one user solved the issue of the bed drive belt slipping by tightening a loose eccentric nut on the roller wheels under the bed.

The video below will show you how to adjust and properly tighten the eccentric nuts.

4. Install a Cooling Fan or Heatsink

To fix the 3D printer belt slipping, many users suggest installing a cooling fan or heatsink on the stepper motors. Since the stepper motors are always “ON”, the drivers can overheat causing the belt to slip or the motor to skip steps. 

Some users fixed the issue by installing a 4cm heatsink and a cooling fan on the motor or by keeping the controller board well-ventilated. Lowering the current for motors by a few milliamps can also help. 

Before installing heatsinks/cooling fans, testing the motor is ideal. One user had to replace the motor as it was defective and causing the belt to slip or shift layers.

With its modern design, smooth operation, stability, durability, and precision, Noctua’s NF-A4x10 is one of the better cooling fans from Amazon. 

Another good option is the UMLIFE 3D Printer Cooling Fan which can be installed using adhesive tape, straps, or zip ties. The fan quickly reduces the motor’s temperature by around 20-30% or 10-20°C, as mentioned by different users.

You may combine it with the EasyCargo 40mm Heatsink Kit from Amazon. It can easily be installed on your stepper motors because of double-sided adhesive tape backing.

The thermal conductive tape ensures efficient heat transfer between the stepper motor and the heatsink. 

Here is an interesting way of keeping the stepper motors cool using a heatsink and laptop fan.

5. Check Pulley for Any Damages

A damaged pulley with broken or missing teeth can also cause the belt to slip and replacing the pulley can fix this issue. If the pulley’s teeth are broken, it may not hold the belt firmly.

A freely spinning belt can usually slip out even with the slightest movement or speed change. 

Since belts are mostly made of Kevlar while the pulleys are made of nylon plastic (it may vary depending on the brand and type of your 3D printer), one user got all the X-axis pulley teeth burnt with one slip of the belt. So, consider replacing the pulley if it’s damaged. 

Read the manufacturer’s instructions for the size and type of pulley best suitable for your 3D printer. You can find many options, such as the Black GT2 Pulley 20T from Amazon.

It fits perfectly and works well with the Ender 3, Ender 3S, Ender 3 Pro, Ender 5, CR-10, CR-10S, and many more.

6. Ensure Correct Motor Driver Current

Another way you can fix a 3D printer belt slipping is by ensuring the correct current supply to the drive motor. Where too high current can overheat the driver, setting it too low can cause the motor to skip steps leading to belt slipping. So, finding the right balance can resolve this issue. 

Although the Creality mainboard pots are factory-set, it’s better to periodically measure and adjust the VREF especially if your 3D printer belt is slipping even when properly tensioned.

Pots/Potentiometers are small adjustable electronic components used to customize various parameters by rotating them clockwise or anti-clockwise.

You can adjust the voltage using a screw-like component (pot) next to each driver on the mainboard. 

Here is a video on how to measure and adjust the current/VREF on Ender 3. 

One user also said that incorrect current causing motor skips is the most common reason for belt slipping, especially if the X-axis gantry is moving at high speeds. In such a case, try reducing the acceleration and print speed.

Here is another video on adjusting the voltages to bring the stepper motor’s temperature down.

7. Replace the Damaged Belt/Bearing

If the bearings or belt is damaged, replacing them with new ones is the only way to fix a 3D printer belt slipping. The teeth of the belt and bearings are responsible for the controlled movement of belts. If teeth are damaged, the belt will slip sometimes even if a couple of teeth are broken. 

Check for any wear or stretched areas in belts. Inspect the reverse side of the belt for any damaged or missing teeth. If the belt itself is worn out, simply replace it with a new one.

Ensure that the bearings are accurately aligned with pulleys and that nothing is there that could cause bumps such as damaged or tight v-rollers. Residues/debris on the axis and bearings without lube can also cause the belts to slip. 

One user also recommended using a bearing with teeth that too should match the gap between the belt’s teeth. This will ensure a strong grip and control movement. 

As suggested by another user, check if the belt feels greasy as sometimes, they come with residues from manufacturing that cause them to slip from the pulleys.

You can find hundreds of options compatible with your 3D printer. However, some of the best 3D printer belts on Amazon include:

• Official Creality Timing Belt
• HICTOP 3D Printer Belt
• AIWAN LEZHI GT2 Timing Belt

Check out the video below on replacing the X and Y-axis 3D printer belts.