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How To Make Your 3D Print’s Bottom Layer Smooth

When you print a 3D object, you won’t be able to see or feel its bottom layer until it has finished printing. But it’s essential to get a smooth bottom layer because it’s the foundation for the entire 3D structure. So how do you make sure that you achieved a smoother bottom layer for your 3D object?

To make your 3D print’s bottom layer smooth, you can do bed leveling since an even printing surface plays a big part in it. You can also make sure your printer’s nozzle isn’t too far or close to the bed. Other solutions include adding a raft and adjusting the temperature of your nozzle and bed.

In this article, you’ll learn about why a smooth bottom layer for your 3D print is crucial. You’ll also learn why this layer isn’t always smooth and how you could fix the problem.

Why Your 3D Print Needs a Smooth Bottom Layer

When printing 3D models, having a smooth bottom layer is important because this layer represents the foundations of your 3D object. A smooth and flat initial layer means your print started well and the rest of the process is less likely to have any issues. In other words, this first layer determines the overall success of your print.

What It Means To Have a Bottom Layer That Isn’t Smooth

A bottom layer that’s bad or that is not smooth can lead to any of these problems:

Bad Layer Consistency

If the height of your bed isn’t properly calibrated, your print is likely to end up having an inconsistent layer. However, an inconsistent layer is more of an aesthetic issue, with the side laying flat on the bed looking unpleasant.

Bad Bed Adhesion

A bad initial layer could cause your 3D print to not adhere to the printing bed properly. And when these bed adhesion issues happen frequently, you won’t be able to expect your printer to do well when it comes to long printing processes. 

Long prints could last days, and for the process to go smoothly until it’s finished, your 3D model needs its initial layers to be stable and to be held firmly in place. Without proper adhesion, your print won’t have the stability it needs to see the process through completion. The filament could also get dragged around the extruder.

Elephant Foot

Sometimes, bottom layers are bad because your 3D printer’s extruder is too close to the bed. This, in turn, can cause the excess filament to be pushed outwards. As such, the first few layers are going to look over-extruded. The imperfections will, however, start disappearing the more layers are printed.

Things You Can Do To Make the Bottom Layer Smooth

There are a few possible reasons why the bottom layer of your 3D print isn’t smooth. You can try different solutions to improve the quality of your first layer, depending on what you think is causing the problem. Here are some of the things you can do:

  1. Level Your Print Bed

Sometimes, bad and cluttered bottom layers occur because of an uneven print bed or build plate. As such, it’s essential to make sure that this plate is perfectly flat and level. A printing bed that’s calibrated, properly leveled, and deformation-free will give you uniform lines in terms of height and consistency.

When it comes to leveling the build plate, you’d need to consider the type of 3D printer you’re using. Some types of printers automatically adjust the bed level, while others require you to change it manually. 

Adjusting the level of your print bed manually can be difficult. Aside from following the directions indicated in your printer’s user guide, sometimes you’ll also need to do a bit of practice or a fair share of trial and error before you get to master the fine art of leveling. It can also get a bit tricky when other printer settings come into play, and you’d need to find the perfect recipe for everything.

Check out this video to better understand leveling and other print settings:

Meanwhile, if you think your print bed may be warped, you might consider getting a glass build plate instead. 

It’s also imperative that you make sure your print surface is clean for good adhesion.

  1. Adjust Distance and Height of Printer Nozzle

First layer issues could arise when a print nozzle or extruder is too far or close to your build plate or bed. So it’s important to set up your print nozzle’s distance and height properly. 

If your extruder is too far, the print lines will look stringy, disconnected, and lacking in uniformity. But more than the appearance, this also means poor bed adhesion, which could compromise the success of the printing process and the quality of the output.

The filament could also get dragged around the extruder if the bottom layer doesn’t adhere to the print surface and isn’t held firmly in place on the bed.

Meanwhile, if your extruder is too close to the bed, the bottom layer of your print would feel rough. Moreover, the first layer of print could result in a mass of filament spreading or smooshing on the build plate.

In some cases, the opposite happens, and the printer’s motor won’t be able to extrude all the filament required because there’s just too little space between the nozzle and the build plate. This, in turn, could damage the print.

Take a look at this video to see what excess or lack of distance between the nozzle and the bed can do to your print:

  1. Set Temperature of Print Bed and Nozzle

Make sure you set the appropriate temperatures for both your nozzle and print bed. To increase the consistency, adhesion, and appearance of your print’s first layer, you can set the temperature of your nozzle to slightly higher than the normal printing temperature. 

While some people suggest lowering the temperature of the print bed to help eliminate blobs or clumps that were created in the first layer, others also discourage cooling the first layer of your print. The longer this layer stays hot, the better it binds to the build plate.

You can set the temperature by hand or by a slicer. But always remember to return to the normal temperature once the first layer has been completed.

  1. Slow Down Printing Speed

Reducing the standard printing speed for the bottom layer of your 3D object to 50 or 60 percent can also help reduce the force applied to the molten filament or plastic. You can readjust the speed to normal for the succeeding layers. This would then lessen the possibility of poor bed adhesion.

  1. Print With a Raft

Adding a raft, which is a rough sacrificial surface that acts as a support material for your 3D structure, can also help you get a good first layer. You can break the raft away after the printing process is complete.

The downside, however, is that printing a raft consumes time and therefore means completing the printing process much later. It also means using up material or filament that you’d just end up throwing away.

Other tools you can use to improve your print are brims and skirts.

Conclusion

It’s important to have a smooth bottom or first layer for your 3D prints because it’s the foundation on which the entire structure rests. The smoothness of this initial layer will help determine the success of your print.

To make your 3D print’s bottom layer smooth, see to it that the bed is flat and level, that the extruder is at a proper distance from the bed, and that the appropriate temperatures are set. There are also other workarounds to first layer problems, including the use of rafts and skirts and slowing down the print speed for this initial layer.