3D printing is a delicate process where the amount of plastic the printer extrudes requires to be precisely correct for the print to succeed and manufacture the model without any imperfections.
Unfortunately, as extrusion relies on many variables both on hardware and software levels, there is no magic formula to ensure that the amount of plastic always comes out correctly, and extrusion-related issues make up for a significant portion of 3D printing problems in general.
Today, we will be talking about the common issue of under-extrusion, where the printer extrudes less filament than it actually should for the printing process to be successful, specifically when it takes place on the first layer of the print.
So, what can cause under-extrusion on the first layer of a 3D print?
Here are the common factors that can cause the first layers of your prints to be under-extruded:
- The print bed is not level.
- The Z offset value is misconfigured.
- The initial line width value is too low.
- The initial layer print speed is too high.
- The initial print temperature is too low.
Moving forward, we will analyze the factors that can cause under-extrusion on the first layer in more detail, find out what we can do to fix the under-extrusion problem, and look at the signs that will help us detect the issue as quickly as possible.
What Can Cause Under-Extrusion on the First Layer of a 3D Print?
Under-extrusion of the first layer can happen due to a handful of things going wrong during the 3D printing process, but in most cases, it’s a result of the improper configuration of the first layer settings in the slicer software.
Below, we have listed the potential causes behind the issue of under-extrusion on the first layer of a 3D print, which should act as a guideline to make it easier for you to pinpoint the one that’s causing the issue in your case:
- Print bed leveling issues – A print bed that is not level can cause the space between the nozzle and the bed to become either too little or too great in some regions of the build area, causing the 3D printer to under-extrude the first layers that are affected. In most cases, you should experience parts of the first layer being extruded correctly and the rest being under-extruded due to this issue.
- Misconfiguration of Z offset – Z offset values that are both too high and too low will cause under-extrusion by increasing or decreasing the space between the print bed and the nozzle to levels that aren’t optimal. Assuming your bed is level, a misconfigured Z offset value should create a consistent pattern of under-extrusion throughout the first layer.
- Low initial line width value – A lower than optimal initial line width value will cause a consistent pattern of under-extrusion that will be immediately noticeable compared to the rest of the model, as the layer lines that form the initial layer will be way too thin.
- High initial layer print speed value – Using a print speed value that is too high, especially if you’re using a larger initial line width value or haven’t increased the initial print temperature, will give too little time for the 3D printer to print the first layer correctly, causing under-extrusion.
- Low initial print temperature value – A low initial print temperature value, specifically if you are utilizing a larger initial line width value, can cause under-extrusion since standard printing temperature might not be enough to allow the plastic to flow freely during this stage.
While there are some other reasons that can cause the issue of under-extrusion on the first layer, such as issues with the extruder assembly that prevent the filament from flowing freely during the printing of the first layer, these issues are a lot more likely to cause problems throughout the entire print as opposed to only the first layer.
How to Fix the Issue of Under-Extrusion on the First Layer of a 3D Print?
Due to the issue’s complexity, fixing the problem of under-extrusion on the first layer is mostly about going through the checklist of factors that can cause the problem to appear and taking the necessary steps to correct any possible misconfiguration.
Below is a list of solutions for the potential culprits behind the issue of under-extrusion on the first layer of a 3D print, which we recommend applying one by one until you resolve the issue:
- Correctly level the print bed. A correctly level bed should leave a space that equals the thickness of a paper between the nozzle and the build surface at all points on the XY axis while the printhead is homed. While it’s possible to achieve optimal bed leveling through manual leveling, we highly recommend using an auto bed leveling sensor.
- Re-configure the Z offset value. Configuring the Z offset is value is similar to leveling the bed, where you should aim to leave an amount of space that equals the thickness of a paper between the nozzle and the print bed. To ensure that your bed is also correctly level, we recommend slowly moving the printhead to random areas of the bed and seeing if the space stays consistent.
- Increase the initial line width. We recommend using an initial line width that is at least equal to the standard line width value but going for a higher value is also acceptable to increase the strength of bed adhesion.
- Decrease the initial layer print speed. Using a lower value, such as one that falls between the range of 25% to 50% of the print speed for the initial layer print value, is optimal, which will give enough time for the 3D printer to print the first layer correctly and for the first layer to adhere to the bed well enough.
- Increase the initial print temperature. Setting the initial print temperature to be 10 to 15 degrees higher than the standard print temperature will help the plastic flow smoothly during the printing of the first layer, especially if you are using an increased initial line width value.
As always, conducting a test print after each solution is a good idea to avoid potentially wasting time on other solutions if you have already resolved the problem and also to know which factor, in particular, was causing the issue.
How to Detect the Issue of Under-Extrusion on the First Layer of a 3D Print?
As the issue may not always be obvious if you don’t have prior experience with it, going through a list of signs you should observe in the case of this particular problem being present is the best way to confirm the issue before applying solutions.
The primary signs of under-extrusion on the first layer are the appearance of gaps and holes as the 3D printer prints the first layer and an overall look that makes it very apparent the first layer lacks the necessary amount of plastic, especially when compared to a successful first layer.
While under-extrusion becomes much easier to spot when it only happens in some regions of the first layer, under-extrusion throughout the entire layer may be harder to notice, depending on its severity, especially if you are not too familiar with how the first layer should look.
As the issue of under-extrusion on the first layer will almost always cause the printing process to fail (due to the model not having a proper foundation), it’s vital to identify and solve this problem as soon as possible to get your 3D printer back in working condition.
The 3D printer can under-extrude the first layer of your prints for various reasons, such as the print bed not being level, incorrect configuration of the Z offset, and issues with initial layer-related parameters such as initial line width, initial print speed, and initial print temperature.
In this case, the issue only happening on the first layer allows us to narrow the potential culprits down a lot, as any other parameters or problems with the 3D printer hardware would cause the under-extrusion issue throughout the entire print.