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What is Layer Height/Layer Resolution in 3D Printing? - RP Space

Layer Resolution

What is Layer Height/Layer Resolution in 3D Printing?

We have heard the word layer height/layer resolution being thrown around, and it is also one of the most commonly changed setting in 3D printing. But what exactly is layer height?

3D printing is a process which fabricate parts layer by layer, and as the name suggests, layer height is the height of each layer. 

Layer Height of 3D Printed Part
Layer Height of 3D Printed Part

In FDM 3D printing, the common layer heights are 0.3mm, 0.2mm and 0.1mm, where 0.2mm is the most commonly used layer height.

These layer heights are sometimes expressed in microns (micrometres), where 0.1mm is expressed as 100 microns, 0.2mm as 200 microns and so on.

 

Why Bother Layer Height?

The reason layer height is sometimes referred to as layer resolution is simply because the layer height affects the surface smoothness of the printed part.

The lower the layer height, the smoother the surface of the printed parts.

Layer Resolution
Layer Height of 0.3mm (Left), 0.2mm (Middle) and 0.1mm (Right)

Therefore, layer height is an important setting especially if the surface of the 3D printed part needs to be smooth.

If that is the case, why not we just use the smallest layer height for all prints? We all want smooth prints don’t we?

 

Speed vs Quality

Printing a part with lower layer height indicates more number of layers are needed to complete the model.

Lower Layer Height Needs More Number of Layers
Lower Layer Height Needs More Number of Layers

This indicates that printing parts with lower layer height will eventually increase the time taken to finish the print.

So it comes down to the choice between speed and quality.

If the surface smoothness of the 3D printed part is part of your concern, going with lower layer height will create a smoother surface and is definitely worth the extra time needed to complete the printing.

If the surface smoothness of the 3D printed part is not part of your concern, consider going with higher layer height to allow for faster printing.

And if you are using 3D printing service, going with higher layer height is usually cheaper and have slightly shorter lead time than lower layer height. So you will save time and money for using higher layer height.

 

Curved and Angled Surface

Despite the fact that lower layer height will result in smoother surface, the effect varies greatly depending on the shape of the part.

The effect of layer height is usually more significant and more obvious on parts with curved and angled surfaces, than on straight vertical faces (based on direction of z-axis).

Effect of Layer Height More Significant on Curved and Angled Surfaces
Layer Height of 0.3mm (Left), 0.2mm (Middle) and 0.1mm (Right)
(Effect of Layer Height More Significant on Curved and Angled Surfaces)

As you can see from the cube shapes below, the layer height only determines how many layers are needed. But the end product for all three, looks… just the same.

Layer Height Has No Effect on Vertical Walls
Layer Height Has No Effect on Vertical Walls

This is because the surfaces of the cube shapes above are all vertical straight faces (based on direction of z-axis), which do not show any difference even though the layer heights are different.

However for curved and angled surfaces, the effect of layer height is significant. Pictures below illustrate the effect of layer height on curved and angled surfaces.

Effect of Layer Height on Curved Surface
Effect of Layer Height on Curved Surface
Effect of Layer Height on Angled Surface
Effect of Layer Height on Angled Surface

As shown in pictures above, layer height has significant effect on the surface smoothness of curved and angled surfaces.

Does that mean as long as the model has curved or angled surfaces, you should use lower layer height? If you need a smooth surface, then in most cases, yes.

However, there are some exceptions for simpler models.

 

Orientation Matters

If you have noticed in the above pictures, we emphasize that the layers are built in the z-axis direction.

Also, the effect of layer height on curved and angled surfaces is significant when the surfaces are in the z-axis direction.

What if we change the orientation of the model?

Pictures below shows the difference in surface smoothness when a part with a curved surface is printed with different orientation. Note, both parts were printed with 0.3mm layer height.

Original Printing Orientation
Original Printing Orientation
Difference in Surface Smoothness
Difference in Surface Smoothness

As you can see, just by changing the orientation to have the curved surface oriented away from the z-axis direction, we are able to achieve a smooth surface.

Therefore, just by paying attention to the printing orientation can help you achieve smooth curved and/or angled surfaces without the need of lower layer height.

However, this may not be achievable for certain models because certain complex models may have multiple curved and/or angled surfaces facing multiple directions.

For these complex models, some of the curved and/or angled surfaces may be forced to face the z-axis direction. Therefore, these models would require a lower layer height to achieve a smooth surface.

 

Conclusion

Layer height is the height of each layer used to print the parts. It is one of the most commonly changed settings used to control the surface smoothness of the 3D printed parts.

The lower the layer height, the smoother the surface of the part.

However, with every advantage comes with its own disadvantage. Using lower layer height requires more number of layers to complete a part, therefore requires a longer print time.

If surface smoothness if not a big concern, using higher layer height will save you time, and if you are using a 3D printing service, will usually save you money as well since higher layer height usually cost less to print.

 

However, it does not mean all model that need a smooth surface have to be printed at lower layer height. For example, vertical wall printed in the z-axis direction will have a smooth surface at any layer height.

On the other hand, curved and angled surfaces when printed in the z-axis direction, will benefits significantly from printing in lower layer height.

However, if your model consists of curved or angled surface, you can change the printing orientation to have the curved or angled surface face away from the z-axis direction to achieve a smooth surface without the need of using lower layer height.

Take note that this would be difficult for complex models which have multiple curved and/or angled surfaces facing multiple direction. If you are using 3D printing service, it is best to discuss with the service provider to decide on the best printing orientation to achieve the desired print results.

 

If you wish to 3D print your own 3D model(s), do check out our 3D printing service.

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