3D Printing Stringing: How to Avoid It?

Do you want to know everything about stringing that can appear on your 3D prints and how to effectively fix this issue? At Imprimy, we are here to guide you.

What is stringing?

3D printing stringing is a defect characterized by the appearance of thin strands or threads between different parts of your 3D-printed object. However, it is possible to identify the cause of this issue and take steps to fix it.

The definition of stringing

Stringing, also known as the “hairy effect,” is a common phenomenon in 3D printing where thin plastic strands appear between different parts of a 3D-printed object. This occurs when filament continues to ooze from the nozzle during non-printing travel moves, creating unwanted strings.

This issue is often caused by improper settings for extrusion temperature, retraction, or the printer’s travel speed. Since stringing can affect the final appearance of a print, there are several methods to minimize or eliminate it, allowing for improved 3D print quality.

The main causes of stringing

The main causes of stringing in 3D printing are related to several technical factors:

• Extrusion temperature too high: If the filament becomes too fluid, it can ooze during the print head’s movements.
• Improper retraction settings: Insufficient retraction, where the filament is not pulled back adequately before a travel move, can lead to material leakage.
• Slow travel speed: A slower travel speed increases the risk of filament forming strands between different areas of the print.
• Moisture in the filament: If the filament is poorly stored and absorbs moisture, it can exacerbate this issue by altering its physical properties.

What are the technical causes of stringing?

An extrusion temperature that is too high

An extrusion temperature that is too high can make the filament too liquid, allowing it to flow even when extrusion is paused. This causes unwanted filaments to form, potentially linking different parts of a 3D-printed object. Each type of filament has an optimal temperature range, and exceeding this range increases the risk of stringing.

By adjusting the extrusion temperature to a more appropriate level, you can reduce these leaks and improve the overall quality of your 3D prints.

Retraction settings

Retraction settings play a key role in preventing stringing. Retraction involves slightly pulling the filament back from the nozzle before it moves without printing, to limit material leakage.

If the retraction distance or speed is not properly adjusted, the filament may continue to flow, leading to the formation of unwanted filaments on your 3D print. A retraction that is too weak or too slow will not be sufficient to prevent these leaks, while excessive retraction can cause under-extrusion.

Therefore, you should test and optimize these parameters based on the type of filament you’re using to achieve high-quality 3D prints.

Travel speed

The travel speed of the print head, when it moves without printing, has a direct impact on stringing. If this speed is too slow, the filament has more time to ooze from the nozzle, forming unwanted threads between different parts of the printed object.

By increasing the travel speed, you reduce the oozing time and, consequently, the risk of stringing. An optimal speed setting allows the print head to move quickly between areas without printing while maintaining the quality of the part.

Filament humidity

Moisture in the filament can greatly contribute to stringing. Filaments easily absorb moisture from the air, especially materials like PLA and nylon. When the moist filament is heated in the nozzle, the water inside vaporizes, creating bubbles and causing material leakage in the form of fine threads.

This phenomenon not only affects the quality of your 3D prints but can also cause other defects. To prevent this, you should ensure that your filaments are stored in a dry environment and dry them if necessary before each use.

How to prevent and correct stringing in your 3D prints?

To reduce the risk of stringing in your 3D prints, you should adjust the printing temperature, optimize your retraction settings, increase the travel speed of your print head, and ensure proper storage of your filaments.

Adjust the temperature

Adjusting the printing temperature is a key step in reducing stringing. If the temperature is too high, the filament becomes too fluid and tends to ooze, leading to the formation of unwanted threads. To minimize this phenomenon, you should gradually lower the extrusion temperature until you find the right balance. The temperature should be low enough to reduce oozing but high enough to ensure proper adhesion and extrusion of the filament during printing.

Each filament has an optimal temperature range, and precise adjustments within these limits can significantly improve the quality of your 3D prints by reducing stringing.

Optimize retraction

Optimizing retraction is essential to prevent stringing. Retraction involves slightly pulling the filament back from the nozzle before a travel move, reducing the risk of oozing. For effective optimization, it’s important to adjust both the retraction distance and speed.

A retraction distance that is too short will not pull back enough filament, while a too-long distance can cause under-extrusion issues. Similarly, a retraction speed that is too slow allows more time for the filament to drip. Testing and adjusting these parameters, specific to each type of filament, helps improve print quality by significantly reducing stringing.

Increase travel speed

Increasing the travel speed of the print head is an effective method to limit stringing. When the head moves without printing, a slow speed allows the filament to ooze and form threads between printed parts. By increasing this speed, you reduce the oozing time, which decreases the formation of unwanted filaments.

However, it is crucial to find a balance: a travel speed that is too fast can affect the accuracy of the movements. Adjusting this parameter, often available in slicing software, contributes to a cleaner print with less stringing.

Store and manage your filaments

Properly storing and managing your filaments is crucial to avoid stringing. Filaments can absorb moisture from the air, which can cause unwanted leaks during printing. To prevent this, it is recommended to store filaments in dry environments, ideally in airtight containers with desiccant packets to maintain low humidity levels.

Additionally, before using a filament that has been stored in humid conditions, it is often helpful to dry it using a specialized filament dryer. Proper filament storage and handling also help reduce stringing and improve the quality of your 3D prints.

What materials and types of filament can influence stringing?

Depending on the specifics of the filaments you use for your 3D prints, you may experience more or less stringing on your final print.

The behavior of PLA with respect to stringing

PLA (Polylactic Acid) is generally less prone to stringing compared to other materials, but it is not completely free from this issue. PLA tends to produce less stringing due to its thermal properties, but if not properly set, it can still suffer from it.

To minimize stringing with PLA, it is crucial to adjust the extrusion temperature, keeping it slightly lower than the recommended range, and optimize the retraction settings. By adjusting these parameters, you can take advantage of PLA’s properties to achieve cleaner prints and reduce unwanted threads.

The behavior of ABS with respect to stringing

ABS (Acrylonitrile Butadiene Styrene) is more susceptible to stringing than some other materials due to its high extrusion temperature and melting properties.

ABS tends to ooze more easily, which can lead to the formation of unwanted threads between printed areas. To reduce stringing with ABS, it is important to properly set the extrusion temperature, keeping it within the recommended range without exceeding the maximum temperatures that could encourage oozing.

Additionally, correctly adjusting the retraction settings and increasing the travel speed of the print head can also help minimize stringing. Strict control of these parameters is essential to achieve clean prints with ABS.

The behavior of PETG with respect to stringing

PETG (glycol-modified polyethylene terephthalate) is particularly sensitive to stringing due to its high viscosity and melting properties. This material tends to ooze more, creating unwanted threads between printed parts.

To manage stringing with PETG, it is essential to slightly reduce the extrusion temperature below the recommended maximum range to prevent excessive fluidity. Optimizing the retraction settings is also crucial, as PETG may require more precise adjustments to prevent filament leaks.

Finally, increasing the travel speed of the print head can help reduce the time during which the filament has the opportunity to ooze and form threads. These adjustments allow for better stringing control and cleaner prints with PETG.

What tools and tests should you use to diagnose and fix your stringing issues?

Finally, to reduce the effects of stringing on your 3D prints, you should not hesitate to perform calibration tests and use software features that will help make your 3D prints sharper and more precise.

Perform calibration tests

Performing calibration tests is essential to optimize printing parameters and reduce stringing. These tests allow for precise adjustments to elements like extrusion temperature, retraction settings, and travel speed. For example, you can print temperature towers to identify the optimal temperature for the filament, or retraction towers to determine the ideal distance and speed to avoid filament leaks.

By conducting these tests, you can directly observe the impact of each setting on stringing and adjust the parameters accordingly. This helps improve the quality of your prints by reducing filament-related defects.

Software features

Slicing software features play a key role in managing stringing. Tools like Cura’s “combing mode” help minimize non-printing moves by guiding the print head along already printed areas, thus reducing the risk of thread formation.

“Wipe” and “coasting” are other available options that help eliminate filament residue before and after travel moves, reducing oozing. By using these features, you can adjust print settings more precisely to limit stringing and improve the overall quality of your 3D printed parts.

Conclusion: Stringing in Your 3D Printed Parts

In conclusion, stringing is a common challenge in 3D printing that can affect the quality of your printed parts by creating unwanted threads between printed areas. To reduce it effectively, it is crucial to adjust several parameters, including extrusion temperature, retraction settings, travel speed, and filament management. Using advanced slicing software features and performing calibration tests will also help refine your settings and achieve sharper results. By adopting these best practices, you can minimize stringing and improve the quality and precision of your 3D prints.

Picture : Imprimy.com

The articles published on Imprimy.com are for informational purposes only. They are intended to provide general advice and information related to 3D printing. Imprimy.com cannot be held responsible for the results obtained or the consequences arising from the application of the shared information. We recommend always checking the specific instructions for your hardware and materials before use.