3D Printing Basics: What Is Z-Seam?

Everyone familiar with FDM 3D printing knows about layer lines. They’re an almost ever-present menace, limiting the final quality of all prints. Unfortunately, this isn’t the only downside of the additive manufacturing approach. At the start and end of each layer, the plastic simply can’t be smoothed together, leaving a visible seam. Depending on your slicer settings, this can leave a visible seam all the way up the side of your print. Given that this seam runs up the Z-axis, it is known as the Z-Seam.

Fortunately, there are some things you can do about the Z-seam. They all revolve around configuring where the layers start and end. Though the exact options available to you – and their names – will vary depending on the slicing software you use, most options will give you at least two choices. These will generally be named something like “shortest” and “random.” Shortest sets the start point of one layer to be as close as possible to the endpoint of the previous layer. This means you end up with a perfectly vertical seam, which is very visible.

Random, randomizes the start point of each layer, meaning you don’t get a single visible seam. It is important to remember that you will still get the seam on each layer, however. All that has happened is that these imperfections are spread across the model, potentially making it harder to hide. Depending on the use of your model, positioning a single seam on the side of a model you plan to be hidden or facing a wall may be the preferable option.

More Advanced Options

Some slicing programs may offer other options, including choices to align the seam with the sharpest corner of the model. This will somewhat reduce the obviousness of the seam compared to it being in the center of a flat or curved face. You may also be able to place the seam on the interior of the model. This is the most effective method of hiding the seam, but it may not be possible on all models and doesn’t affect the top or bottom-most layer.

Conclusion

Z-seam is a printing artifact caused by the nature of progressive layer-based printing. It often results in a single vertical artifact that looks like a fabric seam. It can generally be hidden inside or at least spread over the model’s surface with some configuration. If you’ve got any other tips for hiding the Z-seam, let us know down below.