3D Printing Shrinkage Test: Quick Guide 2025

Reducing stringing in 3D printing is not a matter of luck, but of good setup. Learn how to do a shrinkage test and forget about stringing.

If you’ve ever 3D printed and gotten those annoying threads between parts, welcome to the club. It’s not black magic, it’s simply the retraction set incorrectly. Without the retraction, every time the nozzle moved between two points, it would leave a trail of filament like a spider web. The extruder retracts the filament, pushing it slightly inward to avoid these annoying strands.

Now, mastering shrinkage is a very useful skill, but it is not easy.

OrcaSlicer Retraction test configuration

This is where the game begins. If you set the retraction too low, you get threads. If you overdo it, the nozzle can clog. So you have to find the right spot.

Retraction distance: How much is ideal?

• It starts with 0 mm and goes up 0.1 mm by 0.1 mm up to 2 mm.
• If you have a Bambulab, the best value is usually around 0.8 mm.

💡If you start with 2 mm at a stroke and it jams your nozzle, don’t say I didn’t warn you.

Retraction speed: Faster is not always better

• By default, 30 mm/s is recommended.
• If there are still threads, try 45 mm/s.

Raising the speed can avoid threads, but also strain the extruder. If you hear strange noises, slow down.

Cura Retractions Test

Activate the Auto Towers extension.

Before you start, install the Auto Towers extension in CURA. It’s very easy and only takes a few seconds from the Marketplace.

2. Select retraction distance

Choose “Retract Tower – Distance 1-6”. This range covers ideal values for:
✅ Bowden: 4-6 mm
✅ Direct Drive: 1-3 mm

3. Adjust retraction speed

Add “Retract Tower – Speed 35-75”.

Running the Retraction Test

It is time to print the famous retraction tower. This is not only for postureo, but to see at what height the threads disappear.

Note: The test performed from Cura and Orcaslicer is equally valid .

Printing parameters for the calibration of the retractions:

• Temperature: The temperature obtained from the temperature tower test.
• Flow rate: The flow rate obtained in the flow test.
• Bed temperature: 60ºC.
• Printing speed: 45mm/s | 30mm/s.
• Filling: 50%.

How the “shrink tower” test works:

• It is printed in sections, each with a different shrinkage.
• As the tower rises, the shrinkage increases.

How to interpret the results:

✅ If the threads disappear in one section, that is your optimum value.
❌ If the threads are still up, check other factors:

• Temperature: Figutech ONE usually does well between 200-210°C.
• Mouthpiece: Make sure it is not worn.
• Filament: If it is wet, it will give you problems.

If you see the tower printing like a spider web, check the temperature before touching the retraction.

Adjust and Optimize Configuration

You already have the magic number, now it’s time to set OrcaSlicer to always use it.

Update filament profile

Go to Filament Settings and set the optimum distance you found.

Adjust speed if fine yarns are still present

• If filament remains: Increase the speed a little.
• If the material is delicate: Lower the speed to avoid jamming.

Activate “Wipe while retracting”.

This option tells the nozzle to wipe while retracting, which further reduces threads. It is not mandatory, but in some cases it helps.

If you activate this option and suddenly your printer starts to leave more marks, deactivate it. It is not always the best solution.

Additional Tips for Calibrating Retraction in Orcaslicer

• If you still have threads, check the humidity of the filament.Figutech ONEPLA filament is excellent, but like any PLA, if it gets wet, it will make you suffer.
• Avoid raising the retraction too high. More than 2 mm on a Bambu A1 is to risk clogging.

Frequently Asked Questions on the Calibration of Retractions

1. Can I download a specific STL to perform the shrinkage test?

Yes! There are multiple models designed for this test. One of the most popular is the “Retraction Tower” from Thingiverse, which you can find here: Download STL for Retraction Test. There are also options in Printables such as Control3D’s Retraction Test or others in Cults 3D if you prefer alternatives.

2. Can I do this shrink test on my printer if it is not Bambu Lab?

Of course! Shrink calibration is compatible with all FDM printers, regardless of brand. It works on popular models such as:

• Creality (Ender 3, Ender 5).
• Prusa (MK3S+, Mini+).
• Anycubic (Kobra, Vyper).
• Elegoo (Neptune 3/4).
  Just make sure to set the parameters according to the type of extruder (Bowden or Direct Drive).

3. How does hotend temperature affect shrinkage?

The temperature directly influences the flowability of the filament. If it is too high, the material may leak even with optimum shrinkage. If it is too low, shrinkage will not compensate for stringing. We recommend combining this test with a temperature tower for best results.

What shrinkage values are “normal” for flexible filaments such as TPU?

Flexible filaments (TPU, TPE) require short and slow retractions to avoid clogging:

• Bowden: 2-4 mm at 20-30 mm/s.
• Direct Drive: 0.5-1.5 mm at 15-25 mm/s.

Try a specific test for these materials.