3D printing: Stringing, retraction, dry storage

Lisa Ernst · 20.11.2025 · Technique · 7 min

We still vividly remember our first prints with endless fine threads between the parts – classic "cobwebs" from PLA. At first glance, this may seem harmless, but it immediately makes the part less professional. At the same time, one often doesn't know whether to adjust the temperature, retraction, or filament. We encounter exactly these kinds of stringing problems almost daily in our workshop at 33d.ch – and yes, it happened to us at the beginning too. In the following sections, we will show you using our practical experience how to get these threads under control step by step.

Source: Own Representation

Stringing is one of the most frequent topics in FDM printing courses and support emails we receive from hobby makers, schools, and SMEs. Those who ignore it waste printing time, have to painstakingly remove threads, and risk errors on functional surfaces. The good news: with a few targeted tests on retraction, temperature, travel, and dry filament storage, the problem can usually be very well reduced in practice – without having to buy new hardware.

Stringing Fundamentals

The goal is a clean print without fine threads between individual printed parts. Such threads are called "stringing" or "oozing" – the molten filament drips while the print head travels and pulls thin threads between already printed areas. In our workshop, we particularly notice this with tall, slender parts that are somewhat spaced apart. (Source)

Use cases: For example, if your model has several small, separate towers or if your print head travels over open areas – precisely then, stringing is particularly noticeable.

Important Technical Terms:

• Retract or retraction = withdrawal of filament in the nozzle, so that less material escapes during travel. (Source)
• Nozzle temperature = temperature of the nozzle; too high means filament becomes very fluid → more dripping. (Source)
• Filament moisture = filament has absorbed water and steams when heated → uncontrolled escape of filament. (Source)
• Infill = simplified, the interior of the part; high infill values prolong printing time but usually have less influence on stringing than retraction and temperature.

Preparation for Testing

Before you get lost in the settings, a quick checklist is worthwhile. This way, you can prevent false conclusions like "the slicer is to blame" when in fact the nozzle is just dirty or the bed is warped.

• Current slicer (e.g., Cura, PrusaSlicer, or similar tool) and a simple stringing test (several small towers with spacing).
• Printer mechanically in order: clean nozzle, correctly adjusted print bed, calibrated extruder (step width, feed rate).
• The planned filament – ideally not completely soaked from the workshop air, but dry and ready for use.
• Keep filament storage in mind: store open spools in a dry container or box with silica gel if possible.

At 33d.ch, we've made it a habit to always run stringing tests with the same reference model. This way, we can see at a glance whether something has actually improved or if we are just deceiving ourselves with a "better feeling." Prepare small, clearly defined parameter ranges for these tests – for example, steps of 5°C for temperature or 0.5–1 mm for retraction.

Step-by-Step Guide

In the next step, we'll go through the typical adjustment screws in a sensible order. If you only change one parameter at a time, you'll quickly see which change really helps – anything else makes little sense and just costs filament.

Step 1: Prepare Test Print

Goal: A baseline on which you can track changes. Procedure: Select a model with separate islands or towers (e.g., five cylindrical towers spaced about 10 mm apart). Slice with your default settings (e.g., retraction = 2 mm, speed, etc.). Start the print and then assess: Do fine threads appear between the islands? Then proceed. Success Check: no cobweb-like threads visible anymore = good start.

Source: china-gadgets.de

Different degrees of stringing on test objects used for calibration.

Step 2: Adjust Retraction

Goal: Activate and optimize filament retraction during print head travel. Procedure:

• Check if "Retract" is activated. If not, activate it. (Source)
• Guideline depending on extruder system: Direct drive starts, for example, at 0.5-2 mm retraction length; Bowden systems rather at 4-7 mm. (Source)
• Retraction speed: Start, for example, at 25–40 mm/s. (Source)

Procedure: Start with your default settings, then increase the retraction length in steps of +0.5–1 mm and test again. If filament under-extrusion or rattling in the extruder occurs, reduce slightly. Success Check: significantly fewer or no threads between the towers.

In our workshop, we've found it beneficial to optimize retraction first before activating exotic slicer features. Those who tweak dozens of special options too early quickly lose track of which setting actually helped.

Source: the3dprinterbee.com

Retraction settings in Ultimaker Cura software.

Step 3: Optimize Print Temperature

Goal: Set the temperature so that filament extrudes well, but does not drip excessively. Procedure:

• Know the recommended temperature range for your filament (e.g., PLA 190-210 °C). (Source)
• Start in the middle range, then lower the temperature in 5 °C steps. (Source)

Example: You are printing PLA at 205 °C – lower to 200 °C → check for stringing. Still threads? Maybe to 195 °C. Caution: Check layer adhesion afterward. Success Check: No more threads + stable layers.

Step 4: Utilize Travel Movement and Slicer Features

Goal: Minimize the time the nozzle travels over open space and can drip. Procedure:

• Increase travel speed (e.g., 150-200 mm/s depending on the machine). (Source)
• Activate "Combing" or "Avoid Crossing Perimeters" – so that the head travels within printed areas as much as possible and not over open gaps. (Source)
• Optional: Z-Hop (nozzle briefly lifts during travel) – can help, but sometimes reinforces stringing, so test. (Source)

Success Check: The test model will show whether no or only minimal threads are pulled between the islands.

Step 5: Filament Quality and Dry Storage

Goal: Ensure that the filament is not moist or of poor quality. Procedure:

• If the filament has been exposed for a long time or in a humid environment, dry it: e.g., in the oven at 50-60 °C for several hours. (Source)
• Store filament dry in an airtight container with silica gel. (Source)
• Observation: Audible popping sounds during printing = indication of moisture. (Source)

Success Check: After drying and storage, no more stringing problems with otherwise identical settings.

At 33d.ch, a simple routine has proven effective: spools that have been left open for a long time or extrude visibly "rough" go into the filament dryer first before important orders. This costs a few hours but ultimately saves significantly more time than reworking heavily stringed parts. (Source)

This video shows you exactly one important step in setting retraction and provides good visual tips.

Common Problems & Solutions

Source: the3dprinterbee.com

Significant stringing on a 3D printed cube model.

The following error patterns are what we at 33d.ch encounter most frequently when customers come with "cobweb problems." A brief summary overview:

Error 1: Stringing despite retraction enabled

Diagnosis: Retraction length or speed too low, nozzle too hot, travel movement too slow. Solution: Increase retraction distance, increase speed, lower temperature. Example: Printer with Bowden system only had 2 mm retraction → with 4 mm, stringing was significantly reduced.

Error 2: Under-extrusion after increasing retraction

Diagnosis: Retraction distance too large or filament poorly fed. Solution: Gradually reduce retraction (e.g., 1 mm less), calibrate extruder. Guideline: Direct drive usually <2 mm retraction. (Source)

Error 3: Stringing only with specific material or color

Diagnosis: This filament has moisture or is a bad batch. Solution: Dry or replace filament; use different settings than for standard PLA. (Source)

Error 4: No improvement despite adjustments

Diagnosis: Nozzle is clogged or significantly worn, filament quality extremely poor. Solution: Clean or replace nozzle; use quality filament. (Source)

Material and Hardware Adjustments

For different materials: PLA is rather forgiving, temperature-wise in the range of 190-210 °C; PETG is more robust (e.g., 230-250 °C) and tends to string more; TPU/Nylon require extra caution (more drying, sometimes longer retraction). (Source)

If you have Direct Drive hardware, you can work with shorter retraction values than with Bowden systems. Slicer features like "Coasting," "Wipe," or "Early Retract" can also help depending on the system. (Source)

In our customer projects, it has become apparent that simply switching from a long Bowden setup to a Direct Drive extruder can significantly reduce the required retraction length. Those who frequently print small technical series save not only threads but also a lot of calibration time.

Those who print many small islands or have very fine details might consider setting "Minimum Travel Distance" smaller in slicer settings so that retraction engages even on short movements. (Source)

Further Resource: More slicer tutorials for stringing avoidance (e.g., combing techniques).

FAQ: Frequently Asked Questions from Practice

Here are answers to frequently asked questions and a summary of the most important findings.

Question: Why do I still have small threads after adjustment?

Answer: Small threads often cannot be completely avoided. If retraction becomes too long or the temperature is too low, under-extrusion may occur. You can remove small residual threads with a hot air gun or brush, but you will usually achieve better values through clean test series with retraction and temperature. (Source)

Question: Will stringing affect my print strength?

Answer: In most cases, stringing primarily affects the surface and appearance. Mechanically, it rarely plays a role, but visually it is unsightly and can make support removal more difficult.

Question: Can travel speed be set too high?

Answer: Yes, if the machine experiences vibrations or inaccuracies due to high speed. Then other errors can occur. Travel speed should be appropriate for the printer – many manufacturers cite ~150-200 mm/s as a good range. (Source)

Question: Do I have to readjust retraction every time I use new filament?

Answer: Not necessarily, but with new material, different colors, or different manufacturers, we recommend a short test print. Different filaments react differently to retraction and temperature.

Question: Does it make sense to only change temperature instead of retraction?

Answer: Lowering the temperature is a good measure – but it is often not enough on its own. If the retraction length is significantly too low, the problem persists. Optimizing retraction + temperature + travel movement together yields the best results in practice.

Mini Conclusion: Keeping Stringing Under Control Permanently

• Print a simple stringing test model first before producing important parts.
• Start with sensible default values for retraction and adjust length and speed in small steps.
• Lower the nozzle temperature in 5°C steps until stringing significantly decreases without affecting layer adhesion.
• Use travel features like high travel speed, combing, and optional Z-hop instead of letting the head slowly chug over open areas.
• Consistently store filament dry – if everything else is correct and the material still "pops" and pulls threads, a dried or new filament is more valuable than hours of fine-tuning.

In our workshop, we have a small calibration profile with proven stringing settings for each material. This way, we only need to make fine adjustments for new projects instead of starting from scratch every time.

Source: YouTube

This second video shows you the mechanics of retraction in detail and how stringing occurs – ideal for deepening your understanding if you want to visualize the processes in the hotend better.

Good luck with clean printing!