The extrusion multiple is also known as the flow rate. This variable refers to the rate at which filament is extruded by the printer. Its value is extremely important because the software relies on it to determine the speed of the extruder motor, which has to be adjusted to accommodate the filament’s diameter and the printing speed. So, let’s learn more about the extrusion multiplier and how to adjust it correctly.
Extrusion Multiplier Settings
Usually, the extrusion multiplier is set to 100%. However, this value isn’t optimal because it should be adjusted based on the type of filament you’re using and other characteristics. Even the brand or design of your printer will have an effect on how this value should be set.
That being said, in the majority of the situations you can get by with an extrusion multiplier ranging from 90% to 110%. You can also calculate the extrusion multiplier more accurately by taking the extrusion width value and divide it by the average measured wall thickness.
However, you can go above these values depending on the situation. For instance, if you’re dealing with under extrusion or over extrusion, you have to take that into account and adjust the setting accordingly.
Before going into more detail, here’s an example of how you can access the extrusion multiplier settings in Cura:
- Select ‘Custom Settings’
- Right-click to open the ‘Configure Setting Visibility’ window
- Select ‘Check All’ to see the entire list of settings, including hidden ones
- Navigate to ‘Material Settings’ and find ‘Flow Rate’ and ‘Initial Flow Rate’
These steps may differ based on the software you use, however, the process should be nearly identical. In addition, you should calibrate your printer before doing anything else because it will influence every setting you adjust, including the flow rate.
Now, let’s see how to adjust the extrusion multiplier to optimize the printer’s performance depending on the scenario.
As you probably already know, over-extrusion happens when the printer extrudes too much material. As a result, we start seeing drooping layers, oozing filament and stringing. In some cases, the printer jams. If you experience any of these issues, you’re dealing with over-extrusion and you may be able to solve it by adjusting the extrusion multiplier.
In the case of over-extrusion, you should reduce the flow rate value in small increments (5%) and run a few tests until you find the ideal setting. However, if that doesn’t improve the quality of your model, you need to start looking at other settings, like print temperature and make some adjustments.
This is the opposite of over-extrusion and is sometimes connected to a bad extrusion multiplier setting. In this case, you should increase the multiplier in small increments (5%) and perform a test after each adjustment. Eventually, the quality of the print should improve. However, just like with the over-extrusion issue, you may have to check other settings as well.
Keep in mind that under-extrusion can also be caused by a clogged nozzle, low temperature, and high printing speeds. If you increase the extrusion multiplier up to around 115% and you don’t see any significant changes, you should adjust the other parameters.
Print Bed Adhesion Problems
Sometimes, adhesion-related problems, such as print separation and warping, can be solved by increasing the extrusion multiplier. If you have calibrated your printer and adjusted the other settings but you still experience poor bed adhesion, try increasing the flow rate value in small increments. By having more extruded material in the first layer, we will get a larger surface that can adhere to the build plate. Just make sure you test frequently and don’t increase the extrusion multiplier too much, otherwise, you will have to deal with over-extrusion and other issues.
Layer Separation (Delamination)
Layer delamination refers to the separation of layers that fail to stick together. This leads to an unsuccessful print, but it can be solved by correctly adjusting the extrusion multiplier.
If you’re dealing with layer separation, try increasing the extrusion multiplier over the default value. After a few incremental boosts, the quality of the print should improve. However, if the adjustment doesn’t help, the problem lies elsewhere and you’ll have to go through a laborious round of troubleshooting to find the culprit.
If you’re dealing with oozing bridges that means the filament extrusion is inconsistent. Alternatively, the flow rate might be set too high for your current project. This can be solved by making adjustments to the flow rate.
If too much material is coming out through the nozzle, you should start lowering the extrusion multiplier in small increments. However, if the extrusion rate is inconsistent, you’ll have to adjust the setting up and down until you find the sweet spot. Just keep changing the value in 5% increments or even smaller to fine-tune the setting.
The extrusion multiplier is a setting that unlocks a whole new world of fine-tuning. Some 3D printing enthusiasts even consider it as cheating, but that’s not the case. This is an important calibration option that will further improve the quality of your prints once you understand how to adjust it correctly. So feel free to experiment with the setting, but don’t forget to factor in other variables like filament thickness, type of filament, over extrusion, and temperature. Once you run a few tests, you should already start seeing good results.