Filament Sticking To The Nozzle: How to Fix It
It's incredible at what point the whole 3D printing industry has arrived. Only big companies could afford a 3D printer just two decades ago. Today, everyone can afford one, and the statistics are not showing any slowdown in the 3D printing industry growth.
But our “machines” are still complex constructs, and we all are facing different challenges with them. And one prevalent obstacle we often faced at the beginning of the “printing journey” was 3D printer filament sticking on the nozzle.
The building blocks of filament-based 3D printing focus on extruding the hot filament using a nozzle and laying it down on the print bed. But when some particles of solidified filament get stuck on the nozzle's tip, often curling around the nozzle's aperture, your printer either refuses to print or prints at a reduced quality.
The most common factors of filament sticking to the nozzle are poor adhesion of the filament to the bed, the suboptimal distance between the nozzle and print bed, height clogged nozzle, inconsistent extrusion, or temperature fluctuation.
In this article, we'll show you how to fix your filament sticking problem. Also, at the end of this post, we walk you through a 3D printer that persistently faces filament sticking issues.
5 Common Reasons for Filament Sticking To The Nozzle
Ideally, the extruder delivers the right amount of filament to your printer's nozzle before finishing the last layer of your 3D print. But it doesn't always happen. Some common reasons we've seen why filament sticks within the nozzle are:
1. Suboptimal Distance Between Nozzle and Print Bed
Having the nozzle too close to the print bed is a common reason that causes the filament to stick to your printer's nozzle. This happens because the nozzle requires a certain amount of pressure on the printer's plate to extrude the filament correctly. Curling starts when the nozzle sits too close to the bed, which eventually sticks to the nozzle's tip.
Source: 3DprintingGeek
In many cases, it clogs the extruder's gears, which becomes highly challenging to remove. How to identify this problem: Check the printer's setup and ensure that the Z-offset of your print head is approximately 80% of the nozzle's diameter.
2. Clogged Nozzle
A partial nozzle blockage causes the filament to curl. With time, the filament residue builds up, especially if a particular filament doesn't appropriately extrude, resulting in thin wads of filaments piling up.
Dirt can also enter the nozzle through the filament itself. Dust particles from the printing environment can get stuck on the filament when you don't store it properly. When you feed the filament, these dirt particles reach the nozzle.
Inside the nozzle, these dirt particles burn, causing a buildup of material that results in clogging. When you use the filament, the dirt finds its way to the nozzle, clogging it completely or partially.
The potential risk of clogged nozzle, source: Ender 3 via Reddit
How to identify this problem: A clogged nozzle shows symptoms, such as missing layers, inconsistent extrusion pattern, stringing, or clicking sound during the extrusion process.
If you see filament curling along with these symptoms, a clogged nozzle could be the reason behind poor-quality prints.
3. Poor First-Layer Adhesion
If you overlook the print bed adhesion during the first layer, your filament might ooze out and stick to the nozzle. Poor first-layer adhesion occurs due to high bed temperature, excessively large layer height, and high printing speed.
Source: 3DprintingGeek
When you expose the filament to a sudden drop in temperature when it exits the nozzle, it results in poor bed adhesion because the filament cools down quickly. Interestingly, the distance between the nozzle and the build platform causes poor first-layer adhesion. When the nozzle stays too close to the build surface, it squeezes your first layers, resulting in uneven extrusion.
The filament does not stick properly to the bed even when the nozzle is too far.
How to identify this problem: Check the distance between the nozzle and build plate in your printer's setting – the Z-offset value.
4. Issues With Your Filament Type
Regardless of the filament material, you will face some buildup in and around the nozzle. Let's explore how different filaments types cause filament buildup:
- PLA: As PLA is famous for its rigidity and low-temperature demands, exposing it to very high temperatures can worsen your problem, resulting in blocked nozzles
- ABS: Though ABS is tougher and more flexible than PLA, it's susceptible to sticking to the nozzle. This occurs because of an inconsistent feed rate and results in filament not coming out of the nozzle as expected. It can even happen if the feed rate is low.
- PETG: PETG has better tensile strength, and this filament issue crops up when the distance between the nozzle tip and bed surface is too low. Due to its viscosity, PETG requires a larger distance.
5. Wrong Extrusion Multiplier Setting
If you've tried and tested all the above settings but are still encountering filament buildup, the problem could be with your extrusion multiplier. The extrusion multiplier or flow rate settings are your 3D slicer settings, instructing the printer how fast to feed filament to the extruder.
When the flow rate is set at high pressure or high speed, it causes filament overheating, and the filament gets extruded all at once.
How To Avoid Filament Getting Stuck With Nozzle
For each of these problems listed above, let’s examine the solutions to prevent the filament from sticking to the nozzle:
1. Ensure the Nozzle Isn't Close to the Bed
Adjustment of the nozzle height can be made in three ways:
- Level the printer bed using an automatic bed leveling system. Medium and premium range FDM printers have an automatic bed leveling feature, whereas, in low-cost printers, you have to level the beds manually.
- If the filament sticking issue occurs only with specific filaments, maintain an optimal distance between the nozzle and the print bed by changing the Z-offset setting in your slicer. Z-offset adjusts the nozzle height in comparison to the zero position.
- Make gradual adjustments to the nozzle height (lowering the nozzle by 0.02 mm increments) to ensure smooth filament flow.
2. Unclog the Blocked Nozzle
While there are many ways to unclog a blocked nozzle, you can use these combinations of easy techniques:
- Remove the nozzle and push a small needle through it to break the particles present inside
- Perform a hot or cold pull to clean out the nozzle thoroughly
- Use good-quality PTFE tubing for a smoother extrusion path
- Ensure the nozzle tip is free from bends
- Feed a nylon-based cleaning filament through the nozzle
- For ABS clogging, submerge the nozzle in solvents like acetone for a few hours
3. Use a Bed Adhesive
Bed adhesives are vital in laying down a good first layer of your 3D print. Adhesives ensure that melted filament sticks to the surface better and stays down throughout the print. Use these techniques to minimize the instance of poor first-layer adhesion and filament not sticking well to the bed:
- Apply adhesive surfaces like Kapton, glue, hairspray, painter's tape, or advanced adhesives like 3D Gloop.
- Another way is to elevate the heated bed’s temperature. This ensures the extruded filament remains in liquid form for a long time, giving it time to attach correctly to your print bed before it solidifies.
- Use the default slicing profile of your printer to instruct the cooling fans to delay the cooling of your first layer for better adhesion.
A word of caution: Read the instruction manual of your 3D printer before choosing an adhesive material because it might cause some post-printing process issues.
Troubleshoot for Different Filament Types
Based on the filament material you use, apply these fixes:
- PLA: Squish down PLA into the build surface to mitigate the filament sticking to the nozzle.
- ABS: Make a slurry of acetone and ABS to improve the first layer adhesion. This creates a strong bed adhesion, reducing potential filament issues.
- PETG: Elevate the nozzle temperature and adjust the build surface to ensure proper adhesion. While PETG prints between 220–260 °C, using it at the high end prevents filament-building issues.
Adjust the Extruder Multiplier Setting
Most slicing software has an extrusion multiplier set to 100%. Decreasing this percentage reduces the extrusion pressure, ensuring less filament buildup.
A word of caution: Not all slicing software uses an extruder multiplier. Some might refer to it as flow rate. So, before fixing, double-check which setting requires adjustment.
Most Affected 3D Printer Printer - Ender 3 (Pro/V2)
Arguably the most affordable printers, Ender 3 Pro and Ender V2 are popular in the 3D community because of their numerous benefits. Despite all its positive traits, these printers are notoriously famous for filament curling and sticking to the nozzle.
Picture of new Ender 3 (Pro/V2), source: creality.com
On the Ender 3, you identify whether it's a filament sticking problem by looking at your 3D prints. If your filament looks thin and has some missing portions, it might be because your printer is not extruding it at an even rate. Troubleshoot this issue by using these steps:
- Decrease the printer's speed to ensure the filament sticks properly to the bed, and increase the temperature for an even flow rate.
- Adjust the nozzle or the Z-distance based on the manufacturer's instructions.
- Thoroughly clean the Ender 3 nozzle.
If none of these troubleshooting steps work, your Ender 3 has a faulty PTFE tube that doesn't fit with the nozzle's surface. The gap between the nozzle and tube accumulates filaments, resulting in reduced filament flow.
To rectify this error, use the hot end fix, which adds a spacer inside the hot end, allowing the tubing to be compressed against the nozzle. This minimizes the gap between the two, resulting in adequate filament flow.
Conclusion
As you've seen, every printer is susceptible to filament sticking to the nozzle. The good thing about this problem is that you don't have to print several layers before you notice something is wrong with your printer.
If you're facing such an issue, it's best to inspect the nozzle for potential clogs, followed by bed leveling. Though you might not find an immediate solution, these are the most common causes and help you with printer maintenance. If your issue persists, experiment with other solutions to ensure a seamless 3D print.
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