3D print stringing, also known as oozing or webbing, is a common issue that can mar the finish of your prints. It occurs when molten plastic leaks out of the nozzle and forms thin strands when the printer head moves from one point to another. Stringing can make 3D prints messy and unfinished, and weaken the structural integrity of the print.

If you're experiencing stringing with your 3D print stringy, don't worry! There are a few simple fixes you can use to solve the problem. In this post, we will discuss the most common causes of 3D printing stringing and provide some quick fixes and prevention tips that you can try.

Facing more than just stringing issues? Take a look at our comprehensive guide to common 3D printing problems!

What Causes Stringing in 3D Printing

"Why is my 3D printer stringing?" This is one of the most commonly asked problems in the 3D printing forum without a doubt. So, what causes stringing in 3D printing? The common causes include:

• Over-high Nozzle Temperature: If the hot end temperature is too high, the filament will be more fluid and more likely to drip out of the nozzle.
• Incorrect Retraction Settings: Incorrect retraction settings like too close retraction distance, or too slow retraction speed, which prevents the filament from retracting in a timely manner, may lead to stringing in 3Dprinting.
• Poor Cooling: If the print head fan is not working properly, or if the temperature is too high, the filament may not cool quickly enough, which can also lead to 3D print stringing.
• Excessive Printing Speed: If the print speed is too fast, the filament will not have enough time to solidify before the print head moves on.
• Nozzle Clogging: When the nozzle is partially clogged, the flow of filament can become uneven, causing uneven deposition and thus stringing.
• Wet Filament: Wet filament causes a decrease in viscosity and steam, which can lead to uneven melting of fillings during the melting process and result in 3D printer stringing eventually.

How to Prevent Stringing 3D Printing?

3D printer leaving strings can ruin the finish of your 3D prints, but it's avoidable with the right techniques. Here's how to reduce stringing 3D printing!

Select Proper Filament

The likelihood of 3D printer filament stringing depends significantly on the type of filament used.

For example, ABS has a higher viscosity when molten, making it less prone to stringing, while PET-G is more prone to coming out stringy due to its sticky nature. 

Additionally, the composition and additives in the filament can affect stringing, leading to variations across brands. To minimize stringing, opt for high-quality filaments with stable melting properties.

Avoid the Filament from Wet

Moisture absorption is a common cause of stringing 3D printing, as wet filament creates steam during extrusion, resulting in bubbles and uneven flow.

Materials like nylon and PET-G are especially prone to absorbing moisture. You can store filaments in a cool, dry place with low humidity instead of areas that are typically more humid.

If your filaments are already wet, you can use a filament dryer to remove moisture from the filaments. If you don't have one, try to bake the filament in a low-temperature oven set between 50-60°C for several hours.

Read this guide: How to Tell if filament is Wet?

Speed Up Retraction and Increase Distance

Retraction is a key setting for reducing stringing. It works by pulling the filament back into the nozzle during non-printing moves to prevent oozing. The optimal retraction settings will vary depending on your printer and filaments.

When the 3D print stringing occurs, you can try to increase the retraction distance and the retraction speed to fix the 3D print stringing.

First, moderately increase the retraction distance, typically by adding 1 to 2 millimeters from the default setting, and then fine-tune gradually.

Additionally, slightly raise the retraction speed, usually by increasing it by 10 to 20 millimeters per second to expedite the retraction process of the filament. This helps reduce the chances of excess molten filament residue between your printed model, minimizing stringing.

Set the Proper Temperature

Different 3D printing materials require different nozzle temperatures.

For instance, PLA generally prints well between 190-210°C, while PET-G often works best at 230-250°C.

If you don't know the optimal printing temperature, check the information provided by the manufacturer regarding the recommended temperature range before printing, and choose the proper nozzle temperature for 3D printing to avoid stringing.

If the 3D prints are still stringy and brittle, you can reduce the nozzle temperature by 5 to 10°C. Don't forget to do a 3D printer stringing test after setting the printer.

The AnkerMake M5 3D Printer features a high-precision direct drive extruder that offers superior control over filament extrusion, ensuring consistent flow at the correct temperature. Its smart cooling system automatically adjusts fan speed based on the print geometry, helping to prevent overheating or undercooling that could lead to stringing. Additionally, the user-friendly slicer software provided with the AnkerMake M5 enables precise adjustments to retraction settings, coasting, and temperatures, making it an excellent choice for achieving string-free 3D prints.

Adjust the Printing Speed

The speed of the printer affects how much time the nozzle spends over non-printing areas, which may cause 3D printer stringing.

To fix 3D printing stringing, you can set the appropriate printing speed in the 3D printer slicer. Increasing the travel speed (150-200 mm/s) minimizes the nozzle's exposure time, reducing the chance of filament oozing.

However, for detailed models, balance travel speed with overall print quality. Additionally, ensure your slicer settings optimize print paths to avoid unnecessary travel moves over gaps, further preventing stringing.

Clean the Nozzle Regularly

A clogged nozzle can cause stringing. Cleaning the nozzle regularly can ensure the filament flows smoothly to avoid stringing and improve the overall quality of your prints. Here are some tips on how to clean up stringing on 3D print.

• Clean the nozzle after every print. After 3D printing, wipe the nozzle outside with a damp cloth to remove daily dust to avoid nozzle clogging. Use a soft-bristled brush to clean the nozzle. This brush should be soft enough so that it won't scratch the nozzle while still being stiff enough to remove filament buildup.
• Regularly clean the nozzle with cleaning filament, a needle, or specialized tools to remove debris. For stubborn clogs, consider using a cold-pull method to clear any melted residue inside the nozzle.

Additionally, inspect the nozzle for wear and replace it if damaged to fix stringing 3D printer, as worn nozzles can lead to uneven extrusion and poor print quality.

How to Fix Stringy 3D Prints?

Stringing can affect the appearance of your 3D print, but it's not the end of the road. With post-processing techniques and adjustments, you can get rid of stringing on 3D prints and achieve a polished result.

1. Manually Remove Stringing from 3D Prints

Use a craft knife, razor blade, or small pliers to carefully cut or scrape off the strings. For intricate models, work slowly to avoid damaging delicate parts. Fine sandpaper can also be used to smooth surfaces where stringing occurs, restoring a clean finish.

2. Apply Heat Treatment

A heat gun or hairdryer on a low setting can help fix stringy 3D prints. Gently apply heat to the affected areas to melt and shrink the strings. Be cautious not to overheat the model, as it can deform the print.

Conclusion

3D print stringing is a common issue, but with the right strategies, it can be effectively managed and prevented. From selecting quality filament to optimizing printer settings like retraction, temperature, and speed, you can stop stringing 3D printing and achieve smoother, cleaner prints. Regular maintenance, such as keeping the nozzle clean and ensuring the filament is dry, further enhances print quality. With these fixes and prevention tips, stringing doesn't have to be a persistent challenge in your 3D printing projects.

FAQ

Can a bad nozzle cause string in 3D printing?

Yes, a clogged, damaged, or worn nozzle can cause stringy 3D prints. When the nozzle does not work properly, the molten filament accidentally leaks out of the nozzle, resulting in stringing. To solve the problem of nozzle clogging, you can clean the clogged nozzle using a fine needle. If cleaning doesn't resolve the issue, it's wise to consider a nozzle replacement.

Does the type of filament impact stringing?

Yes. The type of filament indeed plays a role in stringing during 3D printing. Stringing issues are influenced by the filament's viscosity, melting point, and adhesion characteristics. To avoid the issue, you should consider filaments that are known to be less prone to stringing, like PLA, ABS, PETG, and TPU.

Can stringing affect the quality of my 3D prints?

Yes. If 3D print is stringy, it can reduce accuracy, making your prints look messy. It can also ruin the structure of your prints by creating gaps and voids. Moreover, 3D printer printing stringy can clog your nozzle and cause other printing problems. Thus, for high-quality 3D prints, it is crucial to address stringing issues. By adjusting print settings, taking proper precautions, and properly maintaining your 3D printer, you can reduce stringing and enhance print quality.

Why is the first layer of my 3D print stringy?

A stringy first layer in 3D printing often occurs due to improper nozzle height, excessive extrusion, or filament issues. If the nozzle is too close or too far from the bed, it can cause uneven extrusion. To fix 3D printer stringing first layer, calibrate bed leveling and adjust flow settings.