How Does Print Direction affect Print Strength

Many 3D printing users are already aware that the part strength can vary depending on the direction of the printing.

Today, will discuss the fabWeaver team experiment that was conducted to see how the strength of the ABS filament printout will change depending on the printing direction.

Let's take a look at the actual difference in strength from the fabWeaver team's test.

210902 fabWeaver_Main logo



Why the Strength Varies Depending on the Printing Direction?

FFF 3D printing is the process of building a shape by stacking layers in the height direction (also known as Z-Axis direction)

The basic printing process for FFF 3D printers is the repeating series of actions of melting the materials, applying one layer, and then hardening it over.

During this repeated layer stacking in the Z-axis direction, there will be a significant timing difference on the hardening of the extruded materials, and this inevitably makes the bonding force weaker than printing in the other directions.

Looking at the simple figure below, users can observe how the structure on the right side will be less tolerable to Z-axis forces compared to the structure on the left side.

The fabWeaver team conducted an actual printing experiment to see the difference in strength depending on the printing direction.


different printing direction in z-axis
Different printing direction structure against vertical force


Printing for Test

The test sample for the experiment was printed with the industrial 3D printer type A530 and using the ABS material.

The printing settings were set to the default (density: 30%, infill: line, support: hybrid). One part was printed horizontally lying on the bed, and another part was printed vertically with filled support.

sample printing with different printing direction산업용 3d 프린터 출력 방향 abs strengthHorizontal printing (left) vs. Vertical printing (right)


Test methodology
fabWeaver team then tested each printed part by lifting a pile of A4 paper (500 sheets per stack), and then added proceeded to increase the weight.

산업용 3d 프린터 출력 방향 abs strengthHorizontal printing (left) vs. Vertical printing (right)


Test result

Both printed part were able to bear up to 4 piles of A4 papers (2000 sheets) without any problems.

However, while attempting to lift the 5th additional pile stack, the vertically printed part was immediately broken, while the horizontally printed part could still bear the weight.

The video below shows how the parts, which were printed in different directions, reacted to the same force in a certain direction.

산업용 3d 프린터 출력 방향 abs strengthHorizontal printing (left) vs. Vertical printing (right)

Analysis of the Test Result

Looking at the broken part of the printout, we can see how the print was cut parallel to the layers stacked in the Z-axis direction.

산업용 3d 프린터 출력 방향 abs strength
높이 방향과 수직하게 잘려진 단면

This means that if the applied force is perpendicular to the surface on which the layers are stacked, the overall strength of the printout could be weaker.

When designing a part for 3D printing, such load direction in actual usage should be considered for better load endurance of the printed part.

In the near future we will conduct another test in order to see the difference in part intensity for various 3D printing conditions.


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