3D Printing Guide
3D Print Stringing: Why It Happens & How To Fix It
Scott Gabdullin
Updated on February 17, 2025
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Do you know that feeling when you watch a print finish, only to lift it off the bed and see it covered in frustrating, wispy filament strands? Yes, we’ve been there, too. Stringing occurs when the extruder is moving between two different locations, and it is one of those annoying issues that can make an otherwise perfect print look sloppy. It can appear as light cobwebbing between gaps and thick blobs of extruded plastic linking different sections of your print, making it an issue that needs to be addressed.
But why does it happen? And more importantly, how do we stop it?
Causes of Print Strings
Stringing is one of those frustrations that can turn an exciting print into a disappointing mess. Those annoying strands in your print finish are enough to make anyone want to recalibrate everything. Let’s go over the key culprits behind stringing so you can fine-tune your settings and get cleaner prints.
Retraction Settings Are Off
We’ve seen this happen: long, stringy messes connecting different parts of a print. One probable cause is the retraction settings. Retraction is like your printer’s way of controlling drool. Without it, the filament keeps oozing as the nozzle moves. If your retraction settings are too low or completely off, your printer doesn’t pull back enough filament when moving, and you’re left with unwanted strands.
Tweaking your retraction distance and speed can make a huge difference in keeping prints crisp and clean.
Printing Temperature Is Too High
Printing at too high a temperature is like trying to sculpt with butter on a hot day. It just keeps flowing. When filament stays too liquid, it oozes from the nozzle between print areas, leaving behind fine strings.
Each filament type has its sweet spot, and finding the right temperature is crucial. Dropping it in small steps, like 5°C at a time, can help you find the perfect balance between smooth extrusion and minimal stringing.
Travel Speed Is Too Low
Have you ever watched a slow-moving ice cream cone melt in the sun? That’s what happens when your nozzle moves too slowly.
Slow travel speeds can cause stringing and give filament extra time to ooze out and form strings. Cranking up your travel speed means the nozzle moves faster between print sections, reducing the chance of unwanted strands. Increasing the travel speed of your printers in small increments makes a noticeable difference in keeping prints string-free.
Poor Cooling
Cooling is a game-changer when it comes to preventing stringing. If your filament isn’t cooling fast enough, it stays in a semi-molten state, stretching into those annoying fine strands as the nozzle moves away. Picture pulling a piece of melted caramel; if it doesn’t solidify quickly, it just keeps stretching. We’ve seen this happen countless times, and it’s one of the first things we check when troubleshooting stringing issues.
Double-checking our cooling settings, ensuring our part cooling fan is running at the right speed, and even tweaking fan placement have made all the difference, especially with PLA. But don’t just crank up the cooling. Materials like PETG and ABS need a balance, or you’ll end up with poor layer adhesion. It’s all about finding that sweet spot.
Wet Filament
Wet filament is the silent killer of good prints. If you’ve ever heard popping or seen excessive stringing, there’s a good chance your filament has absorbed moisture. PLA, PETG, and Nylon are especially bad at this, pulling humidity from the air and leading to inconsistent extrusion. Store your filament in airtight containers with desiccants, or use a filament dryer, if needed, to make sure that the filament is dry.
For a list of recommended dryers, check out our article on filament dryers!
Does Better Cooling Reduce Stringing?
The quickest and shortest answer is yes; however, it’s not the only solution.
Cooling plays a big role in controlling stringing, but it’s not a magic fix. If the filament cools too slowly, it remains in a semi-molten state and stretches between gaps, leaving behind thin strands. If it cools too quickly, especially with materials like PETG or ABS, it can weaken layer adhesion and cause warping. We’ve tested this countless times, tweaking fan speeds and adjusting airflow direction just to strike the perfect balance.
For PLA, a strong part cooling fan works wonders, keeping those layers crisp and reducing stringing. With PETG, though, we’ve learned the hard way that too much cooling can lead to brittle prints, so dialing it back slightly is key. If you’re dealing with minor stringing, adjusting your cooling settings might be the last piece of the puzzle, but if retraction and temperature settings are way off, even the best cooling setup won’t save your print.
Finding the right balance for each filament type takes trial and error, but once you get it, your prints will come out clean and string-free.
How To Prevent Stringing in 3D Prints
Eliminating stringing comes down to precision tuning, and trust us, we’ve been through the frustration of troubleshooting it. After countless prints and adjustments, we’ve identified ways that make a difference.
First, take a close look at your retraction settings. If the filament isn’t being pulled back fast enough between moves, you’ll see those annoying strings. We suggest increasing your retraction distance and speed gradually and then testing small adjustments until stringing is reduced.
Next, adjust your nozzle temperature. Filament that’s too hot will continue to ooze even when the extruder isn’t actively printing. Lowering the temperature in 5°C increments can help you find the sweet spot where extrusion is smooth but doesn’t cause excess oozing.
For reference, here are the commonly recommended nozzle temperatures for some of the most popular filaments:
- PLA: 180-220°C
- ABS: 210-250°C (with a 90-110°C print bed)
- PETG: 220-250°C
- TPE: 210-260°C (with a 20-110°C print bed)
- PVA: 160-215°C (with a 60°C print bed)
- TPU: 210-230°C (with a 30-60°C print bed)
If you’re printing with PLA, try starting at around 200°C and adjust as needed. For PETG and ABS, you may need higher temperatures, but keep an eye on over-extrusion. Filaments like TPE and TPU, which are more flexible, might require even hotter settings for proper flow. PVA, commonly used as a dissolvable support material, benefits from a lower temperature to avoid degradation.
Then, increase your travel speed to minimize the time the nozzle spends moving between print areas. If the nozzle lingers too long, the filament will have more time to seep out. A faster movement helps reduce this effect. Generally, a speed of 190 to 200 mm/s will work fine with most printing materials. However, we found that 150 mm/s is the ideal travel speed setting for most printers.
Try to experiment within this range to see what works best for your specific setup. Keep in mind that higher speeds may require additional adjustments to retraction settings to maintain print quality.
Filament moisture is another common issue, so dry your filament properly. We always store ours in airtight containers with desiccants and use a filament dryer when necessary. Always remember that moist filament can cause inconsistent extrusion and excessive stringing, ruining an otherwise perfect print.
If you need a step-by-step guide on drying filament, check out our in-depth article: How To Dry Filament. These steps will make your filament stay moisture-free, and your prints appear perfect every time.
Finally, enable Combing Mode and Coasting, two features that can drastically reduce stringing when used correctly. Combing Mode is a setting that keeps the nozzle traveling within already printed areas rather than crossing open spaces, which helps minimize unwanted filament dribbles. This ensures that any slight oozing is confined to internal structures instead of creating thin strings across open gaps.
On the other hand, Coasting works by stopping extrusion just before the end of a movement, compensating for any excess filament still flowing out of the nozzle. Think of it as an anticipatory shut-off. By cutting off extrusion early, the remaining pressure in the nozzle is enough to finish the segment without causing over-extrusion.
However, keep in mind that too much Coasting can cause gaps in your walls, while excessive Combing may extend print times if travel paths become inefficient. Finding the right balance for your specific filament and printer setup is key to achieving clean, string-free prints.
How to Clean Up Stringy Prints
Now, here’s the tricky part. Even with the best tuning, some prints might still have a little stringing. But don’t worry. Sometimes it happens, and there are easy ways to fix it.
One of our go-to methods is using a heat gun or lighter trick. A quick, controlled pass with a heat gun or lighter can slightly melt and shrink those fine strands, making them virtually disappear. Just be careful not to overdo it, or else too much heat can warp your print.
For thicker strands that won’t disappear with heat, a precision knife is your best friend. We use a sharp hobby knife to carefully trim away any unwanted plastic. It takes a steady hand, but the results are worth it.
Lastly, if the surface still isn’t as smooth as you’d like, consider a little sanding or brushing, which can go a long way in refining your print. Using fine-grit sandpaper, such as 400-600 grit, can help smooth out any rough spots without damaging the overall structure. If you’re working with materials like PLA or PETG, a brass brush can be an excellent tool to gently remove any fine imperfections without scratching the surface.
If you want to go the extra mile, consider wet sanding for smoother results, especially for high-detail models. This method involves using water or a lubricant alongside fine-grit sandpaper to achieve an ultra-smooth finish.
Prevent Stringing Issues Before They Happen
Stringing is annoying, but it’s totally fixable. Retraction, temperature, travel speed, and cooling are the big factors that make or break a clean print. Take the time to tweak these settings, and your prints will come out smooth and clean. And if you still get a few stray strands, a quick cleanup will have your print looking flawless.
Want to take your 3D printing skills to the next level? Check out more of our articles in 3DGearZone, where we break down the best techniques, expert recommendations, and practical tips to help you fine-tune your setup. We have troubleshooting guides on common print issues or ways to perfect every detail of your prints.
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Scott Gabdullin
Scott Gabdullin is a Canadian entrepreneur, investor, and marketing expert who has successfully combined his passion for technology and innovation with a love for adventure and exploration.
Scott brings 12 years of digital marketing experience and a hardcore work ethic to his new passion for 3D printing. If he is not working on this business, he is likely travelling and Overlanding across North America with his wife and 2-year-old son in their Jeep Rubicon.
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