Upper and lower layers, in Cura

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Setting up the top and bottom layers in 3D printing is essential to obtaining a high-quality part. In this article, I will explain how to properly configure these layers to improve the quality of your prints.

Lining top surface layers

“Top liner layers” refers to the number of layers in the top level of the liner.

If you use multi-extrusion, it is recommended to use 2 or 3 layers to improve quality.

Recommendation: If you don't have multiple extrusion disable this option.

top/bottom thickness

Top/bottom thickness refers to the thickness in millimeters of the top and bottom layers.

This value, divided by the layer height, will result in the number of top/bottom layers.

For example a top/bottom thickness of 0.8mm divided by a layer height of 0.2mm will result in a total of 4 top/bottom layers.

A high value ensures that the gaps in the top and bottom layers are well closed, but can also increase print times and the amount of filament needed.

It is used to configure the thickness in millimeters of the upper and lower layers.

It is recommended to use the multiple of the chosen layer height for the top/bottom thickness. For example, if the layer height is 0.2 mm, it is better to use a thickness of 0.8 mm instead of 0.7 mm.

Recommendation: Don't worry so much about the upper or lower millimeters. Just choose how many layers you want above, below and that's it.

Upper or lower thickness (separately)

You can also set the thickness of the top and bottom layers separately.

This is useful for the top, as it will likely take several layers to seal properly and prevent gaps from forming.

Number of top/bottom layers

Instead of setting the height in millimeters can be set to number of layers and the height in millimeters will be calculated automatically.

For example: Number of upper layers 4 * layer height 0,32 mm = top layer thickness of 1,28 mm.

Recommendation: Use a minimum of 4 layers.

Top/bottom pattern

Cura allows you to choose the print pattern for the top and bottom layers.

Available print patterns are:

• Concentric Pattern: is printed from the outside in.

• Lines: Diagonal printed pattern.

• Zig Zag: Diagonally but connecting on its own walls.

Initial layer bottom pattern

Bottom pattern Refers to the pattern of the first layer, as it can be selected separately. Use this feature to print with bottom lines different from top lines.

Top/Bottom Line Directions

It refers to changing the direction in which the lines of the upper and lower layers are printed.s.

They are usually printed in a diagonal direction. Changing the direction of the lines can have a visual impact on the outer layers.

You can experiment with different numbers that would be equivalent to the degrees of inclination of the lines.

You can change the direction of the line by entering for example: [90,0] degrees this would create a horizontal/vertical direction.

Unlined in Z-holes

This option is used to fix small gaps between layers in the Z direction.

Enabling this option will ensure that the layers stick together when printing a fill between the top and bottom of an empty space. Disabling this option will print the top and bottom as they correspond in the model.

Count of additional lining walls

It is possible to add additional walls only for the top and bottom layers.

This replaces the outermost parts with a number of concentric lines. One or two lines improve the roofs and ensure they are more resistant, with a smoother surface.

enable smoothing

At the end of the print, the nozzle moves hot over the last layer, leaving a smooth surface.

It is possible to change the settings to obtain the desired surface result, choosing between:

• Iron only the top layer: apply ironing only to the last printed layer.
• Smoothing pattern: choose the ironing pattern.
• Smoothing line spacing: Sets the space between one line and another.
• smoothing flow: represents a quantity of material extruded during smoothing, leaving the nozzle full can fill some surface cracks.
• Smoothing insert: distance that must be maintained from the edge of the model, since if it is smoothed to the edge it may leave an irregular edge.
• Speed, acceleration and impulse straightening: The speed of the smoothing can be changed to adjust the process.

See more about: “How to activate and configure smoothing in Cura“

Video on Youtube: Alexei's 3D Workshop

Continue reading about fill setting.