Inadequate filament extrusion during printing is known as under-extrusion. This can cause a variety of issues with the printed image, including spaces between layers, layers that are too big, or even tiny spots or holes. When under-extrusion happens, the print strength and quality suffer.
If under-extrusion occurs frequently, the problem may lie with the settings and calibration. If it happens all of a sudden, the problem may be with the hardware. Prior to altering the slicer parameters excessively, make sure to check for hardware faults; this is particularly true if you have previously made successful prints using the same configuration.
What is Under-Extrusion in 3D Printing?
Thin or missing layers, or obvious defects in the part’s structure, are symptoms of under-extrusion, a prevalent problem with FDM 3D printing. Fused deposition modelling (FDM) 3D printers are able to deposit a series of two-dimensional layers made of thermoplastic filament when they are operating correctly. But, there are instances when the 3D printer can’t extrude enough material, and problems like fragile produced parts, gaps, holes, thin layers, and missing layers become apparent.
Under extrusion is the term for the common issue where 3D printers do not produce enough material; it affects every printer user occasionally. Although under-extrusion usually does not indicate a serious hardware fault with the 3D printer, there are a number of possible reasons for the phenomena, making a diagnosis difficult. Printer maintenance, such as cleaning the nozzle, or adjusting the print settings is typically all that’s needed to fix under-extrusion.
Causes of Under-Extrusion in 3D Printing
- The filament spool is stuck
If the filament material wasn’t wound up properly, it may easily become trapped on the spool. However, this problem might also originate from the 3D printer if it does a poor job of rolling the filament thread. Because of the increased friction caused by the spool being caught, the motor struggles to gain a good hold on the material as it is being fed into the printer. In other words, less material goes under extrusion as a result.
- The extruder is clogged
Sometimes, if we aren’t cautious, we may find that filament remnants have jammed the extruder head. When that occurs, the extruder will experience increased friction whenever we feed new filament material. Unfortunately, under-extrusion occurs because this friction is problematic enough to reduce the material’s speed as it travels to the nozzle.
On the other hand, the feeder motor itself can become clogged. So, check that the motor gear that feeds the filament into the nozzle is clean and free of any foreign objects.
- Clogged nozzle
Regular cleaning of the printer’s nozzle is required to maintain it in pristine condition. Over time, filament material might accumulate and eventually block the hole. You will lose the ability to appreciate a well-executed print once that occurs. If you see under-extrusion, it can be because of a clogged nozzle, therefore check and test it thoroughly. To test how well the filament flows through the nozzle, simply press it manually. You need to clean the nozzle if you encounter any resistance or, worse, if the material doesn’t pass through at all.
- The printing temperature is set too low
It is important to monitor the printing temperature at all times. The under-extrusion that occurs when the temperature is too low during rapid printing is due to the material’s flow rate being much higher than the necessary temperature. We can’t feed the material through the nozzle properly because it melts too slowly.
- The High Printing Speed
Another common reason for under-extrusion is having the printing speed set too high. It’s critical that the material’s flow rate be in sync with the print speed. You can’t expect sufficient filament to pass through the nozzle at a speed greater than its flow rate. Take care to gradually reduce the speed until it synchronises with the flow rate if that occurs.
How to Fix Under-Extrusion in 3D Printing
- Maximise the Rate of Flow
Raising the flow rate (or extrusion multiplier) in your slicer is something to consider if you’re still getting under-extruded prints after checking that all of your hardware is in good functioning order and trying the settings advice. Increased filament flow via the nozzle means fuller prints when you do this.
To get it just perfect, play around with the slider by 2.5%. Keep in mind that if you turn this setting up too high, it can jam. There may be a small variation in the required flow rate across various filament brands, colours, and materials. By default, you shouldn’t go above 1.1 (or 110%) in this option. If not addressed, other issues will arise.
Remember to never change this setting if you have successfully printed with the same printer, settings, and material in the past. The problem is probably with the hardware if under-extrusion appears at random.
- Raise the Temperature at Which Prints
You might get purrfect prints if you changed the temperature. varied brands and colours of filament within the same material category will have slightly varied printing temperature requirements. You may need to tweak the print temperature if you’ve simply changed filaments and are suddenly experiencing under-extrusion. Filament won’t flow correctly if the print temperature is too low.
Find the optimal print temperature for your machine and material by increasing it by 5 °C increments. If you want to play around with this setting, you may either print out many tests at different temperatures or make use of a single temperature tower to test multiple temperatures simultaneously.
- Modify the Retraction Parameters
A print can have gaps in it if the retraction settings aren’t right. You may have to tweak your retraction settings if you notice under-extrusion around your prints’ seams or edges. Retracting the filament too slowly or too far will prevent the extruder from feeding enough filament into the nozzle to produce a flawless layer.
Reduce the distance you need to retract by 1 mm each time, and speed up the process by 5 mm/s. When you see that this problem goes away or becomes barely noticeable, stop. You should go back a little bit in your adjustments to distance and speed if you see stringing or blobs in your prints. Never retract less than 2 mm or move faster than 45 mm/s, as a rule of thumb.
- Inspect the Parts of the Extruder
As the extruder feeds and pushes filament to the hotend, it’s possible for some components, particularly the gear system and tensional arm, to wear out and eventually crack or shatter. Reddit users’ reactions to the under-extrusion issue suggest this is a widespread problem with Ender 3.
If the extruder of your 3D printer breaks, it could not feed the filament evenly. Inspection of the extruder for damaged parts and, if required, repair or replacement, is, thus, highly important. It may be worth considering upgrading to a metal extruder if your 3D printer currently uses a plastic one.
Also, the tensional arm and gear systems might be fine, but problems could still arise if the extruder pressure was too high or too low. Therefore, make sure the extruder’s strews or tensions are not excessively tight or loose.
- Inspect the Filament
Verify that the filament is free of knots and tangles that can impede the material’s smooth flow. Be sure the filament’s diameter is the same as your nozzle’s before you begin. Callipers and filament gauges are two measuring tools at your disposal. The proper mounting of the filament spool is also critical for a smooth unwinding of the filament.
Furthermore, make sure the filament you’re using is of good quality; low-grade filament could have diameter abnormalities or even inconsistent material composition. It is crucial to use a clean filament to avoid under-extrusion problems caused by impurities.
Moisture absorption can alter the qualities of filament, therefore it’s important to keep yours in a dry, dust-free place. To keep filament in the best possible condition, think about utilising airtight containers or filament dry boxes.
- Check the Bowden Tube for Excessive Wear and Tier
Problems with under-extrusion might arise if the Bowden tube has any kind of wear and tear that alters the flow of impact filament. While this may not be the most typical reason for under-extrusion, it is still worth checking for problems.
Pay close attention to the points where the Bowden tube bends or enters fittings, but you should inspect the entire tube for obvious indications of damage or cracks.
If you can get your hands on it, take it apart and give the inside of the tube a closer look. Make sure it’s clean and clear of any debris or melted filament. Filament cannot flow freely if there are any obstructions. Getting a new one can be a good idea if you find any major problems.
Which is the best 3D printing software?
There are a lot of best 3D printing software available and SelfCAD is a good example. SelfCAD is an easy to use 3D modeling software that runs both online as well as on Windows and Mac. SelfCAD combines tools for 3D modeling, sculpting, rendering, and 3D slicing and you don’t need to switch to a separate program. After creating your 3D models, you can use the in-built online slicer of SelfCAD to prepare it for 3D printing by generating the Gcode to send to your 3D printer.
[Please you will embed this video: https://www.youtube.com/watch?v=lpf38aMk8d8&t=1405s ]
SelfCAD also offers interactive tutorials, many Youtube videos and an academy to help you learn 3D modeling easily.
Final Verdict
To sum up, a multi-pronged strategy is required to fix 3D printing under-extrusion problems. Maintaining a continuous filament flow requires regular nozzle maintenance, which includes cleaning blockages and debris. To avoid uneven extrusion and maintain filament integrity, it is important to dry the filament properly, particularly when working with materials that are sensitive to moisture. You can avoid overheating and nozzle jams by modifying the printing temperature and other settings based on the type of filament you’re using. Both amateurs and experts may greatly improve the print quality by carrying out the required maintenance and adjustments.