Are you looking at the top layer of your 3D print and wonder why these are so far apart? This is one of many common issues that you may come across when you print out your 3D printing project. The goal here is to take a close look at gaps in 3D prints as well as other issues that can happen in the top layer of your print and how you can prevent these problems from occurring.
So, why are your 3D prints too far apart?
What causes gaps in your 3D prints?
The way that a 3D printer is designed is to save plastic when it’s printing. What this means for you is that the outside is a soft shell while the inside has only about a 30% infill so that it’s pretty hollow inside of the model. The problem is that when the printer uses this same process without giving you the solid exterior that you want for your model. This leads to gaps on the top layer of the prints, which doesn’t give you the look that you want for your model.
It may seem concerning that the center is hollow due to the 30% infill, but the printer is still very capable of creating a sturdy, high quality model while still saving on the plastic used to create it.
How can you prevent gaps in 3D prints?
To fix this issue, there are several different settings that you can select that will fix the problem. You may find that you need to adjust a few different options or you may only need to adjust one or two things. This will take a look at the way to fix gaps in your 3D prints.
- Not adding enough solid layers on top.
One of the first settings for you to take a look at is adjusting how many solid top layers are used for your model. What tends to happen is that if you just put a single top layer over the partial hollow inside, there tends to be sagging in the top layer that creates gaps or makes the prints too far apart. This means that you need to add in additional layers to make sure that you get the solid top that you are looking for.
- Percentage of Infill is Too Low
Even though the inside of the models are partially infilled to save plastic, having too little infill will reduce the stability in the structure and create gaps in the top layer. The top layers will sag under the lack of support, which is why you may need to make adjustments as you go. Maybe you only had a 10% infill, which means you should try to see if a 30% works better. The goal is to still save on plastic while getting the best foundation possible for your print.
- Issue with Under-Extrusion
If none of these other fixes work, there may be an issue with the under-extrusion. What this means is that the nozzle isn’t extruding the amount of plastic that the software thinks or expects it is.
Why are there gaps in the thin walls of a print?
Did you try to print out 3D text, only to have unsightly gaps in various areas of the writing? This is actually a common problem seen since the printer typically uses a fixed-sized nozzle, meaning that you’ll encounter this problem when you are printing out areas with very thin walls that are just a little bigger than the nozzle’s diameter. There are some adjustments that you can make that can prevent this problem, so that you can get that sleek look with your 3D printed text or other intricate designs. These are 2 settings that you can try fixing to remedy this problem:
- Adjust How the Printer Acts with Thin Walls
There are settings for the thin wall type that you are using. The default option is generally to fill the gaps between the thin walls, depending on the specific software you are using. In the gap fill option makes the nozzle move back and forth to fill in the gap. There’s also the single extrusion fill option, which can accomplish filling in this gap in a single shot rather than the back and forth technique.
- Make the Extrusion Width Fit Better
Rather than changing the settings to fill in the gaps better, you can just make the amount of plastic that comes out of the nozzle change. In many cases, you may find that you have more luck changing the amount of plastic that is extruded from the nozzle. This is one of the best options if you have a part with consistent wall thickness.
What are other issues that can occur in the top layer of a 3D print?
Still having problems with the top layer of your 3D print? Here are some common issues that can also occur with the top layer:
- Nozzle is Too Close to the Print Bed
How do you know if this is your problem? There are a few different ways. One way is that the printed line is a lot thinner than you wanted, even to the point where it becomes transparent. Another sign is that the excess filament is squished and then creates a rough surface or wavy patterns on the top layer. The simple fix to this issue is to adjust the nozzle so that it’s further away from the print bed. You could also try adjusting the z-offset value if you are using a tool like the bed leveling sensor.
- Nozzle is Too Far from the Print Bed
The opposite of the previous problem, you may find that the nozzle is too far away from the print bed. If this occurs, you will notice the individual lines that make up the top layer and you will likely see gaps in between these lines as well. This can also contribute to the gaps along the top layer, which negatively impact how your print looks. Again, this can be fixed by adjusting the z-offset value and/or moving the nozzle up.
- Print Has Difficulties Sticking
If you notice that the print is having issues like warping, not sticking to the bed, or the bird’s nest look, your print is having issues sticking. This often means that there is warping as a result of the print not being sufficiently adhered to the bed. This will usually happen to the first layer, but it can happen to the print several layers in. However, if you just notice the warping without the lack of adhesion, this is another issue entirely. If warping is the issue you are dealing with, it can help to create a thicker bottom layer or making sure that the print bed is level when printing.
- Filament Issues
There may also be issues with your filament, which can cause a variety of issues with your 3D print. With the PLA filament, this option works better if it’s squished into the print bed a little more, which is how it gets such good adhesion. PETG filaments tend to print better if there is a greater distance between the nozzle and the print bed, which will avoid issues with the filament getting picked up by the nozzle and leaks onto the print later on in the process. Flexible PLA and TPU will have an easier time adhering to the print bed or a specialized print bed if you print too close to it.