Whether it's for a hobby, in a small custom shop, or in large industrial production, 3D printing has become indispensable and offers virtually limitless possibilities to produce prints large and small in astonishing detail in minutes.

Even modern medicine is using this technology and is already producing prostheses or artificial organ parts using 3D printing.

As great as this printing method is, there is one problem that is particularly annoying: a clogged printer nozzle!

Light clogging of the 3D printer nozzle can be easily removed with a cleaning filament*. Severe clogging can be cleared with needles, acetone, various pulling methods, and high heat. Frequent cleaning with cleaning filament, brushes and paper towels will prevent clogging.

In this text, you will learn how different types of clogging occur, what are the causes, how to clean the nozzle and how clogging can be prevented.

1 Symptoms
2 reasons
2.1 Incorrect nozzle height
2.2 Incorrect temperature setting
2.3 Low quality filament
2.4 Dust and dirt
2.5 Don't burn anything...
3 Nozzle cleaning
3.1 Cleaning the filament
3.2 Pushing thread
3.3 Needle
3.4 Acetone
3.5 "Atomic Pull"
3.6 "Cold drawing"
3.7 Incineration
4 Nozzle replacement
5 Prevention
5.1 Daily
5.2 Weekly
5.3 Monthly
5.4 Quarterly

Symptoms

First of all, let's clear up a very simple question: How can you tell if a printer nozzle is clogged?

The following signs most likely indicate that your printer's nozzle is clogged:

Filament does not feed: If you have inserted filament, your printer has reached the appropriate temperature, and the filament does not flow or flows unevenly, you can be sure that the nozzle is clogged. These include the following features: Filament, i.e. the material your object is printed with does not flow straight out of the nozzle, but twists, flows in a curve, flows in an uneven amount, the filament thread is repeatedly interrupted, or the material does not come out at all.
Your printed object has defects: especially thin areas have holes, edges and borders are blurred.
Extruder makes "clicks": The extruder in your printer presses on the material. If it makes a clicking sound, it means that it is not pressing down on the material, for example because it has hardened and the nozzle is sticking.
If you notice one or more of these symptoms, your printer nozzle is most likely clogged.

Therefore, we want to show you some very practical solutions on how you can easily clean the printer nozzle yourself.

But first, you will know what causes nozzle clogging in most cases. This way, you will not only know what to do if the proverbial child fell into the well. We will also tell you how you can avoid this problem in the future.

Causes

A clogged 3D printer nozzle is caused by burnt material, much like burnt material in a cooking pot.

For example, you have set the wrong temperature for the filament, or the remaining filament from a previous print is burnt on the next print at a higher temperature. There are also filaments made partly from natural material, which contain coarser particles that adhere more easily than synthetic material.

Incorrect nozzle height

Nozzle height adjustment, i.e. Z-coordinates, has a significant impact on the result of clean printing. If the nozzle is set too high, the filament has a long path to the print surface and cools down too quickly. As a result, it loses its shape, does not stick, and your object becomes irregular and / or defective.

If the 3D printer nozzle is set too low, there will not be enough room for the filament to extrude cleanly. The result: a completely smeared thermoplastic!

In bad cases, there is so little room left for the material that it is pressed back into the nozzle by the print surface and there, depending on the type of filament, clogs the nozzle extremely hard. This problem is called "retrograde extrusion".

Therefore, it is very important to set the printer nozzle at the correct height. As a general rule, the height should be less than or at least equal to the diameter of the printer's nozzle, preferably less than a quarter of that diameter.

The extruder then puts enough pressure on the filament to make it stick. It compresses slightly, but does not push back.

Incorrect temperature setting

Setting the right print temperature can sometimes be an art in itself. It is important to maintain a temperature suitable for your material.

PLA is best used at 180°C, ABS at 225°C. Nylon threads tolerate much higher temperatures. There are also nozzles specifically designed for certain materials and especially high temperatures.

If the temperature is set too low, the material does not liquefy properly and settles inside the nozzle. The pressure on the print head increases and the nozzle becomes clogged.

On the other hand, if the temperature is too high, so-called "thermal creep" may occur. The material is heated so much that it becomes liquid long before it enters the nozzle: thus, the heat escapes upwards or backwards.

Liquid filament requires higher pressure. The engine is overloaded, cannot cope, and the nozzle is blocked. In some cases, the material may also dissolve into its constituents and then crystallize in the nozzle head.

Therefore, it is very important to adhere to the correct temperatures!

Practice also makes perfect: with a little experience, you'll quickly determine which material produces the best print results at which temperature.

When changing from one type of filament to another, make sure you always remove all residue from the nozzle so that only the newly inserted material is subsequently heated and the temperature really matches the material in the nozzle.

Also note that media change only occurs correctly when exposed to heat, and that media should not be pushed into the printer with excessive force or pressure.

Low quality filaments

Especially in various online stores, sellers lure buyers with filaments from unknown manufacturers at ridiculously low prices.

It's tempting, of course. Especially if you are new to 3D printing, you will definitely want to try different things and bring all your ideas to life.

This can quickly become costly because good filaments are expensive. Cheap filaments are attractive because of their price, but in most cases they cannot match the quality (exceptions, as always, prove the rule).

Low quality filaments do not have fixed tolerances, which means that the thread of the filament does not have a uniform diameter, or only varies within certain tolerance ranges.

If the thread has a different thickness, then the melting point also varies. Therefore, the filament does not flow cleanly and evenly, which may result in poor print quality and nozzle clogging. In addition, filaments are of poor quality if they are not "clean", ie. contain unwanted ingredients.

They "stretch" the mass to make it bulkier and thus be able to sell large volumes at low prices. Or they mimic the characteristics of established brands with cheaper but lower quality additives.

So before buying cheap threads, do your research, read the reviews and, when in doubt, go for proven products that can cost more. You can also check the quality of the thread yourself by checking the diameter of the thread in different places (best with a vernier caliper*). If the values are very different, it's best not to use a thread to avoid problems.

Dust and Dirt

Dust, dirt and other deposits on the filament "migrate" through the extruder and nozzle during printing. They melt and thus carbonize and therefore become extremely hardened.

An unyielding layer of dirt forms in the nozzle, which narrows the print opening and leads to further clogging.

It is impossible to completely avoid deposits. We have to reckon with and put up with such pollution to a large extent. However, you can reduce their number if, after opening the package, you store the filaments in clean vacuum or at least plastic bags and protect them from dirt. Also, check the floss for cleanliness before each use.

One of the causes of contamination inside the printer may not be so obvious, but is often the cause: the use of spray varnish on the finished object. Many print enthusiasts want to give their prints a colorful look immediately after printing and use a variety of sprays.

They scatter in tiny droplets and settle on and in the printer. It can also lead to permanent clogging of the nozzle and other components. If you use ink sprays, please do so as far away from the printer as possible - preferably not in the same room!

Don't burn anything...

You may be familiar with the following situation: Your printer is printing, while you are doing something else. Perhaps you forget about printing for a while and only when the printer finishes its work, return to it.

But to prevent the filaments from drying out and burning on subsequent prints, you can enter a command to keep the printer warm after printing is complete. In this way, you will keep the thread in a liquid or at least soft state, even if you are not around.

Nozzle cleaning

Now that you know how to recognize a clogged printer nozzle, how it happens, and how to avoid it, we want to arm you for the contingency.

The printer nozzle is clogged, nothing works. What to do?

We have collected cleaning methods that you can try one by one or on your own. You can also repeat each method as many times as you like.

When used correctly, they will not damage your printer or nozzle. Please note that the printer nozzle may be very hot. So be careful.

Depending on how badly the nozzle is clogged, different methods are used:

cleaning filament
Right at the start of our cleaning methods, another tip for prevention: Filament Cleaning*.

The cleaning filaments are made of a special material suitable for cleaning the printer nozzle. They are inserted and then used in the printed passes according to the package instructions. Dust, dirt, filament residue and other deposits adhere to them and are then mechanically removed along with the print.

We recommend carrying out such cleaning operations regularly. Because once the nozzle is completely clogged, even the best cleaning filament won't help.

For it to work effectively, there must be at least a partial flow of pressure. Cleaning threads are quite expensive in the purchase price. However, they need very little for one cleaning cycle!

Fifty grams cost about 20 bucks, but you can do 70 to 100 runs with them. So even if you use the printer regularly and clean it regularly, this amount will last you a long time.

push through the filament

Often unwanted print results do not immediately block the entire nozzle, but only a small deposit forms in the hole and around the nozzle.

With this method, you use white ABS or white nylon in a similar way to cleaning filament - only a little more complicated. So if you need to do it quickly and have a little left, you won't have to wait for the cleaning filament to arrive.

Step 1: Heat the nozzle to 200°C to melt the thread.
Step 2: Remove the filament from the hot tip.
Step 3: Gently clean the outside of the nozzle with a paper towel.
Step 4: Manually push the filament into the nozzle until it stops or until part of the filament comes out.
Step 5: Pull out the filament again.
Step 6: Cut off the dirty/blackened end of the thread.
Step 7: Repeat steps 4 to 6 until the thread remains white.

Needle

This method is based on manually unblocking the blockage with a needle. You can use this method with both cold and hot nozzles.

Set your printer's temperature to the temperature that suits your media. Now insert a very thin and sharp object into the nozzle and move it slightly until the dirt comes out. When you then extrude the new filament (ideally cleaning it first), the loosened contaminants will be squeezed out with it.

Some manufacturers include cleaning kits designed specifically for the printer in the box or offer to purchase them separately. Here you can find these cleaning kits from different manufacturers:

These kits usually include needles or similar cleaning tools that you insert into the printer. If you are stuck with the above home remedies, this set is highly recommended!

Of course, the needle or other cleaning tool should not be thicker in diameter than the diameter of the print hole. In the worst case, you can irreparably damage the hole!

Acetone

If you have used (at least for one of your recent prints) a filament that dissolves very easily, you can also chemically clean a clogged printer nozzle.

For this you need acetone.

Remove the printer nozzle and place it in a container, completely covering the nozzle with undiluted acetone.

Leave the nozzle to soak for at least twenty-four hours and during this time move it back and forth from time to time to loosen the dirt.

In between, you can remove the internal dirt with a needle. Do this as often as needed until the dirt is gone.

"Atomic Pull"

In this method, material is fed into the printer, extruder, or nozzle, and then quickly pulled back out.

The steps between feeding and pulling are different. Basically, you can test all pull methods. Atomic Pull" which we will now explain to you is only suitable for Bowden type printers*.

Atomic sweep uses the same media for cleaning as the print itself. It is heated, then cooled and jerked out again shortly before solidification.

It works like this: First, remove the Bowden hose clamp. Set the printer temperature to 30 degrees higher than what is indicated for the filament you are using. Then insert about an arm's length filament (as white as possible, preferably pure white) until the filament comes out even or you can push it further. Then set the temperature to the following values and wait until the extruder reaches this temperature:

145 °C for nylon
110°C for ABS
90°C for PLA
Once the temperature has been reached, pull the filament out of the extruder again with a firm pull. Do not use force! The thread should come out with only a little resistance.

Now look at the extracted thread. What does its end look like? If the front end of the filament is dirty or discolored, the nozzle is still clogged. Repeat the process until the thread is clean.

If you can't seem to get the rope out, repeat the whole process with slightly higher temperatures until the rope is easily loosened. Then you can repeat the procedure until the thread is clean. After that, your printer should produce perfect results again.

"Cold Pull"

This method is especially suitable for severe clogs and hardened deposits in the printer nozzle. In fact, it is based on the use of very high temperatures.

Heat up your printer to 250 degrees Celsius for at least five minutes. Use nylon or ABS filament. They are extremely heat resistant. Push the filament by hand through the printer or extruder.

Under the influence of strong heat, the settled dirt and thread residues are loosened and fused into the nylon/ABS used. The blockage is then squeezed out along with the nylon/ABS. Let the printer cool down until the nylon/ABS hardens. Then heat up the printer to a temperature of 120-130 degrees Celsius. Then pull out the filament with a jerk. This jerky movement of the cooled material gave the name to the method.

Burning

This method can be considered as an "emergency solution". It combines uncontrolled heating and manual effort.

Remove the nozzle from the printer. Hold the nozzle with pliers over a strong flame, such as a gas or Bunsen torch, blowtorch, or hot air gun. Hold the nozzle over the flame with the print hole facing down.

If material is now dripping from the hole, the deposits have loosened. If you hold the print nozzle with the opening towards the light source, you can see if it is already free and if light can pass through it.

If this is not the case, hold the nozzle over the flame again and at the same time pierce the nozzle hole with a pointed object to further loosen the blockage. You can also lightly tap the nozzle on a hard surface to loosen deposits.

Nozzle replacement

Despite all the preventive maintenance and all the tips for cleaning the print nozzle, it may happen that the nozzle is no longer cleanable and the print still looks unsatisfactory. Then sometimes only buying a new nozzle* will help.

Prevention

As a preventive measure, at the end, we have compiled a small checklist of cleaning tasks for you and divided them according to how often they should be performed.

That way, you'll have a simple list at your fingertips that, along with our tips, will help you keep your printer clean and avoid printer nozzle problems.

If your printer is used daily and constantly, the following checks and maintenance procedures have proven useful:

Daily

Remove dust, dirt, and debris from the printer before using it.
If possible, clean the nozzles automatically before each print.
Check the movement of the axles and all moving parts.
Are the print profiles OK?
If you already know the printer will not be used for the next few days: Remove the filaments and roughly clean the nozzle with a metal or toothbrush and needle (or guitar string or wire brush or paperclip or toothpick).

Weekly

Clean the print bed with a thin spatula and rinse under warm water.
Printer calibration, especially if the nozzle or other has been removed (for example, to clean the nozzle with our nozzles).
Rough cleaning of the nozzle with a metal or toothbrush and a needle (or a guitar string or a wire hair brush or a paperclip or a toothpick).

Monthly

Using cleaning threads*
Complete (Re) Calibration of the Printer
Search for software updates
Clean and oil round rods and bearings
Remove grease from spindles and re-lubricate

Quarterly

Complete cleaning of the extruder
Check all cables and main board