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Martin has a M.Sc. in physics and has gained many years of experience in industry as a lab manager and quality assurance manager. He has now tested dozens of 3D printers and is happy to share the collected experience with each new article.
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The Ender 3* is one of the best lower-end 3D printers on the market today, making it a popular choice for beginners to 3D printing. Despite its many positive features, there is one major weakness: under-extrusion.
Many Ender 3 users regularly report problems with under-extrusion when producing a 3D printed model. However, there are a few tips and tricks specific to this 3D printer that can help prevent under adhesion of your 3D printing.
In the following article, you will find out what solutions are available for under-extrusion with the Ender 3, so that you can avoid faulty printouts in the future. First of all, however, you should check that your device is properly mounted and calibrated and that you have correctly set both the extrusion multiplier and the filament diameter in your slicer.
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Table of Contents:
- 1 What Does Under Extrusion Mean?
- 2 Effective Tips Against Under Extrusion
- 2.1 Tip 1: Increase the extrusion multiplier
- 2.2 Tip 2: Correct the filament diameter
- 2.3 Tip 3: Increase temperature and decrease speed
- 2.4 Tip 4: Cleaning and adjusting the nozzle
- 2.5 Tip 5: Replacing the PTFE tube
- 2.6 Tip 6: Replacing the stock extruder
- 2.7 Tip 7: Repairing the Hot End
- 3 Effective Tips Against Over Extrusion
- 3.1 Tip 1: Reduce the extrusion multiplier
- 3.2 Tip 2: Reduce the print temperature
- 3.3 Tip 3: Correction of the filament diameter
- 4 Related Questions
- 4.1 Why is the printing temperature so important?
- 4.2 What are the best 3D printing temperatures for PLA, PETG and nylon filaments?
What Does Under Extrusion Mean?
Under-extrusion can be observed when too little filament is extruded during the printing process. This results in gaps, missing layers, insufficient layer thickness and even small dots or holes in the layers. When under-extrusion occurs, the overall print quality suffers and even the print strength is affected.
How to Avoid Under-Extrusion on a 3D Printer: Full Guide
Effective Tips Against Under Extrusion
Tip 1: Increase the extrusion multiplier
If your extruder is not extruding enough filament, the most obvious solution is to first increase the setting of the extrusion multiplier or the flow rate in your slicer. This will allow more filament to flow, which usually already results in a satisfactory extrusion.
You should adjust this setting gradually by 2.5 percent until you find the right value. However, you should keep in mind that increasing this setting too much can also lead to interference. As a rule of thumb, the value should not exceed 1.15 or 115 percent respectively, otherwise, further problems may occur.
Tip 2: Correct the filament diameter
Incorrect entry of the filament diameter can also lead to under extrusion. For example, if you tell your slicer that your filament has a diameter of 1.75 millimeters, but is actually 3 millimeters wide, the extruder will not print the filament at a sufficient speed.
Therefore, use a caliper gauge to measure your filament first to determine the correct diameter. It happens that even an inaccuracy of 0.1 millimeter leads to printing problems.
Tip 3: Increase temperature and decrease speed
The flow rate and printing temperature are factors that are easy to overlook. In general, a higher flow rate means that more material is extruded from the nozzle, while a higher temperature can also result in an increase in filament flow. However, you should be aware that too high temperatures can lead to wet spots and tension on the printing surface.
So first try increasing the flow rate by 5 percent and the temperature by 3 degrees Celsius until you get the desired result. However, your printing temperature should not be more than 10 degrees Celsius above your usual temperature.
Tip 4: Cleaning and adjusting the nozzle
It happens that the nozzle partially clogged, which in turn can lead to under extrusion of the filament. The easiest way to solve this problem is to extrude the filament and then check whether it comes out straight or curled.
How to Clean a 3D Printer Nozzle | All Methods Step by Step
If the filament rolls up, this indicates a partially clogged nozzle, which is mainly caused by foreign particles in the filament that cannot be melted and therefore get stuck in the nozzle. If you notice a blockage, you should perform some so-called “atomic pulls”. With a bit of luck you will be able to remove the disturbing material. If this method is not successful, you can push the material through the nozzle with a needle. Be careful not to damage your device.
Another possibility is to clean the filament carefully. However, this is not an acute solution, but rather a preventive measure, as you may not have a cleaning filament available.
Another problem in connection with the nozzle is the distance to the printing bed. If the nozzle is too close to the printing bed, the material cannot flow as intended. Indicators for a too-small distance between the nozzle and the printing bed are extruder jumping noises and a too-thin first layer of your printing model.
Tip 5: Replacing the PTFE tube
Most users do not consider that the PTFE pipe can also lead to extrusion problems. Not all filaments are produced in the same way. If the PTFE tube has very tight tolerances, this means a higher resistance to the filament path. This in turn ultimately leads to a disturbed filament flow and results in under-extrusion.
The easiest way to check the resistance of the PTFE tube is to manually extrude the filament. There should be no resistance and you should be able to push the filament easily through the tube. If this is not possible without much effort, you should replace the PTFE tube.
Tip 6: Replacing the stock extruder
Replacing the stock extruder is one of the most recommended upgrades for Ender 3. The standard extruder set that comes with Ender 3 consists of a plastic extruder that is qualitatively inferior to the metal counterparts and also wears out within a short period of time. Therefore, there is often a problem with the filament that comes out through the arm of the extruder. Some users have also noticed that the extruder tears slightly over time, which in turn leads to a loss of spring tension.
It is therefore recommended to install a new metal extruder, which should solve the problems related to the extruder. The metal extruder is not only stiffer, but also less susceptible to wear. Furthermore, the calibration of the extruder is very important. Poor calibration can lead to under-extrusion, while a properly calibrated extruder will ensure dimensional accuracy and higher print quality.
Best Ender 3 Dual Extruder Upgrades – Complete Guide
Tip 7: Repairing the Hot End
If you have tried all the tips but still find an under extrusion, the problem is most likely at the hot end. The PTFE pipe extends to the nozzle in the heating block at the hot end of ender 3. In principle, the pipe should be flush with the nozzle surface.
However, sometimes a gap can occur between the PTFE tube and the nozzle due to faulty couplings or poor quality control. The filament then seeps out of this gap and accumulates instead of flowing directly into the nozzle. The result is a reduced filament flow, which over time causes the PTFE tube to clog.
To solve this problem in the long run, you should use a washer to ensure that the pipe is flush with the nozzle. Alternatively, you can purchase better couplings and reassemble the hot end.
The opposite of an under-extrusion is an over-extrusion, which can also be regularly observed with Ender 3. As you can see from the name, overextrusion happens when too much material is extruded. This can also seriously affect the print results.
Indications of overextrusion are, for example, dimensional inaccuracies, sagging layers, tension on the surface, wet spots, splotches or even filament jams. In general, overextrusion should always be avoided. There are some effective measures that can be taken to prevent faulty prints caused by overextrusion in the future:
Effective Tips Against Over Extrusion
Tip 1: Reduce the extrusion multiplier
The setting for the extrusion multiplier or the flow in slicer programs decides the extrusion speed of your 3D printer.
In your slicer, you’ll probably find a standard value of 1 or 100 percent. Usually, you will notice that the extrusion multiplier is turned off if you encounter unusually thick layers. If there is too much material extruded, you should gradually reduce these settings by 2.5 percent.
However, if you reduce this value too much, not only will the problem not be solved, but it may also cause further difficulties. In this case, you should check other settings.
Tip 2: Reduce the print temperature
If the extrusion multiplier is not the problem, you should reduce the printing temperature. If the temperature is too hot, the filament will over melt and flow out of the nozzle of your Ender 3 in an uncontrolled way. Reduce the print temperature of your printer in steps of 5 degrees Celsius according to the filament used until you reach the optimal temperature for the device and the material used.
Tip 3: Correction of the filament diameter
Another common cause for the occurrence of under-extrusion is an incorrect entry of the filament diameter. The most common filament diameter is 1.75 millimeters. 2.85 millimeters and 3 millimeters are not that common. If your filament is thicker than the setting in the slicer, it will extrude the filament at a higher speed, which can lead to overextrusion.
Now you have an overview of the settings that you can adjust to fix both under- and over-extrusion and thus avoid faulty prints in the future.
Why is the printing temperature so important?
Although almost every filament used is currently a thermoplastic, the individual filaments also have their own temperature requirements. The reason for this is that the different filaments are very different in their chemical makeup.
Some filaments, such as PLA*, are produced from starch, while filaments such as ABS* are oil-based. This chemical composition directly affects the glass transition temperature. At this temperature, the filament changes from a brittle to a rubber-like basis that can then be extruded.
3D Printing Filaments – 40 Filament Types Introduced
Therefore you have to use specific temperatures for each plastic. Some filaments also require a specific temperature for the heating bed. When certain plastics cool down, they can warp when thy shrink, which can be minimized by using a heated printing bed because the filaments cool down more slowly in this case.
In addition, a heated printing bed provides additional adhesion, thus securing that the bottom layer adheres well and that the print model is not detached from the printing bed throughout the printing process. It is very important to set these temperatures correctly, as this can prevent faulty prints.
What are the best 3D printing temperatures for PLA, PETG and nylon filaments?
Proper print temperature settings are critical to successful 3D printing.
PLA* is currently the most used filament by far. This is partially due to its indulgence in printing requirements. PLA is best printed at around 210 degrees Celsius, but there is a margin between 180 degrees Celsius and 230 degrees Celsius.
A heated print bed is not required, but if the 3D printer has one, it should be set between 20 degrees Celsius and 60 degrees Celsius. Since the best results with PLA are achieved with adequate cooling, the fan should be left on during printing.
PETG* combines many properties of the filaments PLA and ABS. Very high temperatures are required, which should be between 220 degrees Celsius and 250 degrees Celsius. A heated printing bed is not necessary. When printing with PETG, it is best to use some tape on the printing bed. Without the painter’s tape, the bed should be heated to 50 degrees Celsius to 75 degrees Celsius for better adhesion. As there is no danger of the filament warping, no fan is necessary.
Nylon* is a very strong filament, but it is also more difficult to print. It should be printed at very high temperatures between 240 degrees Celsius and 260 degrees Celsius. In addition, the printing bed should be heated to 70 degrees Celsius to 100 degrees Celsius. Furthermore, some sort of spray adhesive or a glue stick will be necessary for sufficient bed adhesion.
Since nylon requires heat for sufficient layer adhesion, the fan should be switched off during the printing process. Furthermore, this filament is hygroscopic. This means that it absorbs any humidity in the air, which in turn has a considerable impact on the print quality. It is therefore necessary to dry the filament sufficiently before printing.
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