5 Ways How to Fix 3D Printing First Layer Gaps


Having gaps in your first layer isn’t a pretty sight, and I’ve definitely experienced my fair share of badly printed bottoms of models. Luckily, I figured out some good fixes for those first layer gaps, which I decided to share in this article.

Making sure your print bed is properly leveled is the most common solution to fixing first layer gaps. A warped bed can also be an issue, so replacing it is a good fix. Increasing your first layer line width to 120% of the nozzle diameter works well to fill in first layer gaps.

There are more details behind this answer which you’ll want to know, so you can properly fix those badly printed first layers once and for all. Keep on reading through this article to solve this issue.

Causes of Gaps in the First Layer of Your 3D Prints

There are a few factors that can contribute to first layer gaps in your 3D prints such as improper settings, or bad 3D printer calibrations of certain parts.

Gaps in your first layer mostly relate to some form of under-extrusion, meaning your nozzle isn’t extruding as much filament as the overall flow rate in the extruder pathway.

Since the first layer is the most important layer of a 3D print, its important we can get this fixed once and for all, but it’s a good idea to first know the main causes behind this.

  • Print bed is not properly leveled or its warped
  • Your printing temperature is too low
  • The line width setting in your slicer is too high
  • Under-extrusion, which has various causes
  • Incorrect Z-offset settings

How to Fix Gaps in the First Layer of Your 3D Prints

To get this problem fixed efficiently, it’s a good idea to narrow down the possible causes that are negatively effecting your first layers.

Although going straight for the root cause is the best idea, it’s still worth checking over some of the other factors since it can result in higher quality 3D prints in the future.

Most of the time, you can fix gaps in the first layer of your 3D prints by changing your 3D printer settings, from temperature, to extrusion down to cooling. If you can’t solve it by adjusting settings, then there is usually a hardware problem that needs to be fixed.

If you have identified the actual cause, below are the simplest and most effective solutions that will be helpful no matter if you are facing first layer gaps in Cura, Slic3r, Ender 3, or any FDM 3D printer.

1. Level the Print Bed & Check it Isn’t Warped

One of the first things you should take into consideration is how level your print bed is. If the bed is not level properly, the filament may not extrude as expected causing gaps in the first layer.

A badly leveled bed isn’t ideal, so I would recommend upgrading your bed compression springs to tougher ones, or even getting silicone leveling columns. What they do is keep their sturdiness and position more stable over time, meaning less need for leveling so often.

You can’t go wrong with the SIQUK 16-Piece Heated Bed Springs from Amazon. They have a 4.7/5.0 rating, and work really well.

If you compress the BCZAMD Heated Silicone Leveling Column properly, they really stay in place. Some people have had these in for months and still not had to re-level their beds!

Sometimes it’s just not possible to level the bed at all because it is warped or curved. In this case, you can either put a glass plate on top of the warped surface, or just get yourself a fresh build platform.

You can check whether your bed is warped by first heating it up to your normal printing temperature, then placing a ruler or long flat object on it to test it. Glass print beds are superb at staying flat, so you can get a borosilicate or tempered glass bed surface.

Find a great glass bed on Amazon by clicking here.

  • Make sure that the print bed is leveled accurately and the surface is not unsteady.
  • Get a new build platform if the old one gets too warped after heating.

2. Increasing Your Printing Temperature & Bed

If you’ve checked your bed and it’s flat and leveled, but you are still getting first layer gaps, we can try adjusting the printing temperatures.

Your temperature settings can definitely contribute to first layer gaps in your 3D prints, mainly due to having a bad flow of filament through the nozzle. If your filament isn’t reaching the ideal temperature, it isn’t going to flow as well as you need it.

The nozzle can then start to have trouble pushing that filament out, leading to those first layer gaps.

So the simple fix here would be to increase your nozzle temperature and see if the problem gets solved.

You can also increase your bed temperature so the material doesn’t cool down too quickly. This is the main reason why your 3D printer defaults to having no fans for the first layers.

Make sure you are priming your nozzle beforehand by adding ‘Skirts’ in your slicer settings.

If your fans are blowing for the first layers, you definitely want to adjust that to be off.

Some people who changed their nozzle to a stainless or hardened steel nozzle may realize that they require a higher printing temperature for the same filament when using a brass nozzle.

Brass nozzles have the best thermal conductivity, so they don’t require as high of a heat. Making sure you are using a brass nozzle can help in the consistency and heat transfer of the temperature.

3. Adjust the Line Width

Still having issues? I’d look towards adjust your line width in your slicer. There is a direct setting in Cura called ‘Initial Layer Line Width’ which is defaulted at 100%.

Some people have got better printing results by increasing that line width to 120%, or even in some cases, higher print quality by using a more narrow line width. I’d start off with increasing it and seeing if it fixes those first layer gaps in your prints.

If that doesn’t work out, try reducing your Initial Layer Line Width setting.

Many users claim that they have got better results by reducing the line width. People say that the line width equal to the nozzle diameter is the most ideal line width to get high-quality prints without any flaws.

  • Adjust your Initial Layer Line Width settings

4. Adjust Flow/Extrusion Rate

Under extrusion comes into play when talking about gaps in a 3D print. A good fix is either increasing the temperature, like mentioned above, or increasing your flow rates in your slicer.

Adjusting your flow rate isn’t ideal though, because it’s fighting the symptom rather than the cause.

I’d recommend checking out my article on How to Fix 3D Printer Not Extruding Enough (Under-Extrusion).

There is a direct relation but the quick answer is increase your printing temperature, calibrate your extruder, and have a good filament pathway to the extruder and nozzle.

Under extrusion can be caused due to different reasons and you have to check all these things to make sure that you can fix the problem efficiently.

Implement the following suggestion for the first layer only and then you can print the whole project with your regular settings.

  • Make sure that the nozzle is not clogged and the extruder motor and other related parts are working properly.
  • Increase your flow rate to 105% to see whether it helps out the issue

5. Adjust Your Z Offset

The Z-offset is a setting in your 3D printer that adjusts your print head to compensate for the positioning of your bed leveling sensor or your limit switches.

You’ll notice this as your 3D printer hits the limit switch and adjusts its height as it moves closer to the bed.

The video below explains how to perfectly adjust your Z-offset for a great first layer

There are tuning settings that you can adjust in your 3D printer to move the nozzle up or down. The best thing to do is start a print with many skirts and do ‘live leveling’ which is leveling while the print is extruding.

This is sometimes known as ‘Baby steps’.

If the nozzle is too close, you’ll see extruded filament that digs into the bed and looks scratchy. If the nozzle is too far, the extruded filament will be easy to remove from the bed, meaning barely any adhesion.

  • Change the Z offset step by step and see if the problem goes.
  • Do test prints while changing the Z offset after each step and when you find out the perfect spot then start your actual project.

Bonus Methods to Fix First Layer Gaps

BL Touch

Implementing automatic bed leveling is a solution that many people jump over to when it comes to leveling their beds. Some people do have problems with setup and issues, but most of the time it goes pretty smoothly.

You’re less likely to run into problems by getting the official BL Touch Auto Bed Leveling Sensor from Amazon.

Use a Tried & Tested Printer Profile

Try using slicer profiles that are tried and tested. You can find some awesome profiles for your 3D printer, especially from YouTubers like CHEP. Go to Google and type in ‘3D printer + profile’ and you should find a few to try out.

Cura usually has pretty good profiles in there already.

Change Your Slicer Software

Another thing that can solve your issue is by using a whole different slicer software. I know some people can have issues with a slicer, then change to a different one and it makes their prints a lot better.

An example is even with a specific version of a software like Cura 4.7, which was known to produce zits and blobs in 3D prints, much of which I experienced myself. Reverting to Cura 4.6 solved the issues here.

There are many slicers that you can change to, giving you a way of seeing if it’s a software problem. Sometimes changing your slicer can improve your print quality significantly, so it’s definitely worth a try.

Slicers to try are:

  • PrusaSlicer
  • Slic3r
  • KISSlicer
  • Repetier-Host

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