Tolerance of lattice struts manufactured without supports via fused filament fabrication

Abstract Additive manufacturing (AM) processes enable the fabrication of customized and complex parts, such as lattices or porous structures. These structures offer advanced properties that are difficult to achieve with conventional manufacturing techniques. Complex geometries often require support structures to ensure stability during the printing process. The use of supports limits the AM’s capability to produce lattices because the removal is complicated or even impossible. Consequently, there is a growing focus on research and innovation aimed at achieving self-supporting structures for customized internal infill designs. This work examines the capability of fused filament fabrication (FFF) to manufacture millimeter-sized struts as elemental construction units of internal lattices. Specifically, we investigated the influence of material density $$\rho $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>ρ</mml:mi> </mml:math> , overhang angle $$\theta $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>θ</mml:mi> </mml:math> , and strut diameter D on the quality (dimensional and geometrical tolerances) of the printed struts. The use of main effect plots, a nonparametric statistical method, and a factor ranking procedure to analyze the tolerance estimations performed by means of optical techniques yielded that $$\theta $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>θ</mml:mi> </mml:math> is the most critical parameter regarding dimensional tolerances and roughness. On the other hand, $$\rho $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>ρ</mml:mi> </mml:math> proved to be the key factor for parallelism and straightness, while D influences straightness and roughness.