The 3d printer works by using high heat to melt the filament, the melted filament will pass through the nozzle and form the printed object by layers. With such a method of operation, it is inevitable that the nozzle will get dirty, clog over time and adversely affect the 3d printing process.
Not only affect print quality, but dirty nozzles also reduce the life of the nozzles and in general affect your 3d printer.
The following article will guide you step-by-step to clean the nozzle from the inside out. In addition, we will also offer cleaning methods suitable for each type of material as well as different types of printers like Ender 3, Ultimaker s3, Prusal, Formlabs.
Contents
Signs that you need to clean 3d printer nozzles
Sign 1: Missing first layer
Missing the first layer is one of the most common signs that your nozzle is dirty or clogged. The reason is that when the filament is melted and flows to the nozzle, the flow is blocked due to an obstruction in the tube.
The consequence of missing the first layer is that your 3d print will lack detail or even warp. The image below describes the differences between Missing first layer and Over extrusion in 3d printing.
Sign 2: Extruded material do not flow straight down
This is one of the common signs when your nozzle is clogged. You will see extruded material does not flow straight down. The reason is that the material is blocked in the nozzle, affecting the flow of the extruded material.
Sign 3: Dust
Dust around the extruder or motor parts is also a clear sign that you should clean the nozzle.
If there is too much dust on the nozzle or other parts such as cooling fans, extruders, the quality of 3d printed products will be significantly reduced. When there is a lot of dust on the cooling fan, it will affect the rotation speed and reduce the cooling capacity of the fan.
Sign 4: Inconsistent extrusion
When the nozzle is dirty or clogged, the most obvious sign is that the nozzle extrudes unevenly. Due to a clogged nozzle, sometimes the nozzle extrudes too much in a short time.
This leads to a lot of reduced quality 3d printed products, even causing warping or breaking in parts. It also makes it harder to remove your 3d print from the printer bed because the amount of extruded material will be more than usual.
Note: Sometimes uneven extrusion can also occur due to wet filament. When the filament is wet, the melting point of the filament will also be different between the wet part and the dry part. This is the cause of the clogged nozzle. Thus, it’s important to keep filament dry to prevent nozzle blockage.
Sign 5: Under extrusion
Under-extrusion occurs when too little filament is extruded during a print. When under-extrusion happens to your 3d printer, the 3d printed object will experience a lack of layers, lack of detail. In addition, you will notice small dots or holes on the surface of the object after the print is completed.
One of the most common causes of under-extrusion is a clogged nozzle. However, under extrusion can also be caused by settings from the slicer software. Make sure that under extrusion is not caused by settings from the slicer software before performing hardware repair.
Note: While the above signs are the most common signs that the nozzle is dirty or clogged, they do not guarantee 100% that your nozzle is clogged. You need to carefully check and rule out other possibilities before proceeding to clean the nozzle.
Steps by steps to clean 3d printer nozzles
Step 1: Cleaning around the nozzle
Things to prepare
| Soft bristle toothbrushes: Soft bristle toothbrush used to clean dirt around the nozzle | 
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| Brass brush: Brass brush used to clean excess melted material that got stuck around the nozzle. Since we will heat the nozzle to the melting point of the material for cleaning, it is necessary to use a brass brush | 
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Clean the outside of the nozzle first, there is usually a lot of dust and excess melted material that got stuck around the nozzle.
Use a soft-bristle brush to clean the dust first. After cleaning the dust, use the brass brush to clean excess melted material around the nozzle.
Before cleaning with the brass brush, heat the nozzle to filament melting temperature (or a slightly higher temperature is better). Once the temperature is sufficient, use the brass brush to scrub the areas of the material.
To avoid excess melted material that got stuck around the nozzle in the future, you can raise the Z offset and leveling the print bed.
Video for reference
Step 2: Unclog Your 3D Printer’s Nozzle
If the nozzle is clogged, we will proceed to push out the leftover material and clear the nozzle opening. There are several ways to unclog a nozzle, I will show you how to do it easily and get the best results.
Note: method 1 and method 2 only apply to partial clog, not full clog
Method 1: Use cleaning filament
Things to prepare
| Cleaning filament: Cleaning filament is a special filament created to clean 3D printer nozzles. When used correctly, cleaning filament will remove any filaments left in your nozzle from previous prints. | 
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How it works
The reason cleaning filament is so effective in cleaning nozzles is that it has a higher melting point than other types of filaments. When the cleaning filament passes through the nozzle, the residual filaments will stick to the cleaning filament and go out.
How to do it
If you have a Bowden style 3d printer, first remove the Bowden tube from the extruder head. If you are using a Direct Drive style 3d printer, just use the cleaning filament as normal filament.
Next, set the nozzle temperature to the number that’s above the printing temperature of the filament you last worked with. For example, PLA prints between 190°C – 220°C => We will set the nozzle temperature to 230°C
Next, feed the cleaning filament manually until it starts coming out of the nozzle.
You will see some leftover filament extruding from the nozzle. In most situations, the cleaning filament will have spots of residual material. Continue doing this until the filament has cleaned all the residue.
Method 2: Use the Nozzle Unclogger
Things to prepare
| Cleaning needle: cleaning needle is used to unclog nozzle for a 3d printer, remember to choose the right size needle for your 3d printer | 
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How it works
Nozzle Unclogger is used to unclog nozzles that are long, thin metal objects such as nozzle cleaning needles, acupuncture needles, or just a thin wire.
Usually, when you buy a 3d printer, the manufacturer will include a cleaning needle that is sized to match the size of the printer nozzle. However, if you can’t find the cleaning needle that comes with the printer, you can easily buy them online.
How to do it
First, remove the current filament and heat up your printer to the print temperature so that the leftover material is melted
When the nozzle temperature has reached the melting point of the filament, carefully insert the cleaning needle into the nozzle from underneath. Move the cleaning needle gently around the nozzle so that any remaining filament stuck in the nozzle will be dislodged.
Reference video:
Method 3: Cold pull
Things to prepare
| Filament: You can either use cleaning filament or normal filament like PLA, ABS. |
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How it works
Cold pull is a method of taking advantage of the expansion of filaments at different temperatures to blend leftover filament with cold-pull filament. You can use the cold pull method after using cleaning filament or cleaning needles for the best result.
How to do it
If you have a Bowden style 3d printer, first remove the Bowden tube from the extruder head.
Next, increase the temperature of the hot end to the printing temperature of the filament that you will be using for cold pull.
When the temperature reaches the printing temperature of the filament, feed the filament into the extruder manually until it begins to pour out of the nozzle.
After the filament starts pouring out of the nozzle, stop heating the nozzle and let the nozzle temperature drop to room temperature.
As soon as the extruder reaches this temperature, grasp the filament and pull it slowly but steadily out of the extruder. Make sure to pull straight up, not sideways.
On the tip of the filament that has been pulled out, you can see the material you previously used or some burnt dirt that has accumulated in the nozzle.
Repeat this process several times until the filament is clean.
Method 4: Use a Heating Gun or blow torch
Things to prepare
| Long Nose pliers: used to clamp the nozzle when heating to avoid hand burns | 
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| Blow torch: Used to heat the nozzle to a high temperature, it is very useful, especially for materials with a high melting point | 
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| Cleaning needle: used to unclog nozzle when leftover material is melted |
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How it works
With this method, we will heat the nozzle to a high temperature with a heat gun, then clean the nozzle from the inside out. This method works with virtually all filaments, even high temp filament clogs.
How to do it
First, remove the nozzle from the 3d printer
Next, put use blow torch to heat up the nozzle until it turns red
Now use a cleaning needle to remove all the material stuck in the nozzle
You can also refurbish the nozzle after unclogging it. Put the nozzle into a bowl of cool water. Wait for the nozzle to cool down, use tweezers to scrape around the nozzle.
And this is the final result
Method 5: Deep clean nozzle in Acetone
| Acetone: We use Acetone to break up hardened plastic from a 3D printer nozzle. | 
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| An empty bowl: used to soak the nozzle in Acetone | 
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| Cleaning needle: used to unclog nozzle when leftover material is melted |
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How it works
If you have tried methods 1, 2, 3 and still find the nozzle is not completely clean, it is time to use acetone solvent to dissolve the filament stuck in the nozzle.
How to do it
First, remove the nozzle from the 3d printer
Next, soak the nozzle in the acetone solution for 20-30 minutes
Now, take the nozzle out of the acetone solution
Now use a cleaning needle or a wire to remove all the material stuck in the nozzle
That’s it! Now you have an unclogged nozzle and you can install the nozzle to the 3d printer to start 3d printing right away.
Replacing a new nozzle
If you’ve tried all cleaning methods and still can’t get rid of the dirt in the nozzle, it’s time to replace it with a new one.
There are many different types of nozzles in both sizes and materials, you will choose the right nozzle depending on your needs and the printing material you want to use. Usually, a nozzle with a larger diameter will give a faster print speed, while a nozzle with a smaller diameter will have better detail when printing.
Below I will list some characteristics of the nozzle that will be useful when you choose a nozzle …
Nozzle Diameters
3D printer nozzles come in a variety of nozzle diameters from 0.1 to 2.0 mm. Typically, there are 3 most commonly used nozzle diameters as below
0.4 mm nozzle
This is the standard size, which balances both print speed and level of detail when printing.
0.25 mm nozzle
With this nozzle size, your 3d print will be highly detailed, suitable for designs such as miniatures, small text.
Source: Prusa 3D by Josef Prusa
However, with a small print head, obviously, the print speed, as well as the strength of the print, will be poor
0.6-1.0 mm nozzle
Nozzles with diameters >0.4mm have higher print speed due to higher material extrusion speed.
Prints should also be stronger as they will have fewer layers, but this will result in reduced print detail. In addition, an advantage of a large nozzle is that it minimizes the possibility of blockage.
However, the large nozzle also causes many inconveniences such as
- Lack of details
- too visible layers
- Really hard to remove support
- filament consumption rate
Nozzle Materials
Brass nozzles
Brass is the most commonly used material for 3D printer nozzles. Nozzles are made from brass with low cost and high thermal conductivity, however, they are quite soft and prone to abrasion.
The maximum safe temperature of the brass nozzle is 300°C. Due to such properties, brass nozzles are most suitable for printing non-abrasive materials such as PLA, ABS, and PETG.
Coated nozzles
Coated nozzle is a type of nozzle that is coated with nickel or chromium on the outer surface to increase hardness as well as heat resistance.
In addition, coated nozzle also reduces the friction of the filament with the nozzle, increasing the durability of the nozzle. Although not as durable as a steel nozzle, this is a good nozzle in terms of both cost and quality.
Steel nozzle
There are two types of steel nozzles: Stainless steel nozzles and Hardened Steel Nozzles.
Stainless steel nozzles are slightly more resistant to wear than brass nozzles.
The maximum temperature with stainless steel nozzles is 500 degrees Celsius. Stainless steel nozzles also have good anti-adhesion, reducing the risk of nozzle clogging.
Hardened Steel Nozzles are suitable for even highly abrasive media. The downside to Hardened Steel Nozzles is that the inner surface of the nozzle is not as smooth as other “softer” nozzle materials, which can result in poorer print quality. In addition, the price of Hardened Steel Nozzles is also higher than other nozzles.
Ruby nozzle
Ruby nozzle is the most expensive and luxurious nozzle for 3d printers. Usually, ruby nozzles are made of brass for the nozzle body and have a small ruby at the top.
The ruby nozzle ensures high wear resistance, which is especially useful when working special fibers. Compared to other types of nozzles, ruby nozzles are the most luxurious.
Conclusion
Cleaning the nozzle is one of the very important jobs to help you have a beautiful and quality 3d printed product, but often overlooked. Depending on the degree of nozzle blockage as well as the type of blocked material, you should choose the most suitable cleaning method to avoid damaging the nozzle.
I hope the above article has provided useful information to help you understand how to clean the nozzle effectively and comprehensively.
If you have any questions, please leave them in the comments below, I will be happy to answer!
