Under extrusion is a common problem in 3D printing that occurs when the printer fails to supply enough filament to the nozzle, resulting in gaps, holes, or thin layers in the printed object. The main causes of under extrusion are clogged nozzle, low extrusion temperature, incorrect filament diameter, or faulty extruder.
Under extrusion can ruin your prints and waste your time and filament. Fortunately, there are some easy ways to fix it and prevent it from happening again. In this article, we will explain how to diagnose and solve under extrusion issues in 3D printing, and provide some tips to improve your print quality and reliability.
The first step to fix under extrusion is to identify the source of the problem. There are several signs that indicate that your printer is suffering from under extrusion, such as:
The printed object has gaps, holes, or missing layers
The printed object is weak, brittle, or breaks easily
The printed object has rough or uneven surfaces
The printed object has stringing, oozing, or blobs
The extruder makes clicking or grinding noises
The filament is tangled, kinked, or snapped
If you notice any of these symptoms, you should check the following components of your printer:
The nozzle: The nozzle is the part that melts and extrudes the filament onto the build plate. If the nozzle is clogged, dirty, or damaged, it can restrict the flow of the filament and cause under extrusion. To check the nozzle, you can perform a cold pull or an atomic pull, which involves heating and cooling the nozzle and pulling out the filament with a quick motion. This will remove any debris or residue that may be stuck inside the nozzle. You can also use a needle or a wire to poke through the nozzle opening and clear any blockage. If the nozzle is worn out or damaged, you should replace it with a new one.
The extrusion temperature: The extrusion temperature is the temperature at which the filament melts and flows through the nozzle. If the temperature is too low, the filament will not melt properly and will have difficulty passing through the nozzle. If the temperature is too high, the filament will melt too much and become too viscous, which can also cause under extrusion. To check the extrusion temperature, you can use a temperature tower, which is a test print that consists of different sections with different temperatures. By comparing the quality of each section, you can determine the optimal temperature for your filament. You can also use a thermocouple or a thermometer to measure the actual temperature of the nozzle and compare it with the set temperature on your printer. If there is a significant difference, you may need to calibrate your thermistor or replace it if it is faulty.
The filament diameter: The filament diameter is the thickness of the filament that you use for your printer. If the filament diameter is incorrect, it can affect the amount of filament that is extruded by the printer. For example, if you use a 1.75 mm filament but your printer is set to use a 3 mm filament, the printer will extrude less filament than needed, resulting in under extrusion. To check the filament diameter, you can use a caliper or a micrometer to measure the thickness of your filament at different points along its length. You should also check the label of your filament spool and make sure it matches the diameter that you set on your printer. If the filament diameter is inconsistent or inaccurate, you should adjust the extrusion multiplier or flow rate on your printer or slicer settings, or use a different filament that has a consistent and accurate diameter.
The extruder: The extruder is the part that feeds the filament to the nozzle. If the extruder is faulty, it can cause under extrusion by not pushing enough filament to the nozzle. To check the extruder, you can perform an extruder calibration, which involves measuring the amount of filament that is extruded by the printer and comparing it with the amount that is expected. You can also check the extruder gear, which is the part that grips and moves the filament. If the gear is worn out, dirty, or loose, it can slip or skip and fail to feed the filament properly. You can clean the gear with a brush or a cloth, or replace it if it is damaged. You can also check the extruder tension, which is the force that the gear applies to the filament. If the tension is too low, the gear will not grip the filament enough and cause under extrusion. If the tension is too high, the gear will crush the filament and cause jams or clogs. You can adjust the tension by tightening or loosening the screws or springs that hold the extruder assembly together.
After you have fixed the under extrusion issue, you should take some preventive measures to avoid it from happening again. Here are some tips to prevent under extrusion in 3D printing:
Use high-quality filament that has a consistent and accurate diameter, and store it in a dry and cool place to prevent moisture absorption and degradation.
Use the recommended extrusion temperature and speed for your filament and printer, and adjust them according to the ambient temperature and humidity.
Use the correct nozzle size and type for your filament and print settings, and clean and replace the nozzle regularly.
Use a good slicer software that has the appropriate settings for your printer and filament, and optimize the retraction, coasting, and wipe settings to reduce stringing, oozing, and blobs.
Use a reliable extruder that has a good gear, tension, and calibration, and maintain it properly by lubricating, cleaning, and tightening it as needed.
Use a good bed leveling and adhesion method to ensure that the first layer is printed correctly and sticks to the build plate.
Under extrusion is a frustrating problem that can ruin your 3D prints and waste your filament. However, by following the steps and tips in this article, you can diagnose and fix under extrusion issues in 3D printing, and improve your print quality and reliability. Happy printing!
