Layer combination of similar infill patterns on the tensile and compression behavior of 3D printed PLA

Abstract

With the growing popularity of 3D-printed products, material consumption has been a major concern in additive manufacturing in recent years. Choosing the infill structure and the printing parameters for an application can be challenging for product designers and engineers, which can lead to reduced material and increased cost savings while maintaining product functioning.This study investigates the mechanical behavior of 3D-printed PLA structures by exploring the influence of multi-layer infill patterns on tensile and compressive strength. Three common infill patterns (triangular, grid, and honeycomb) were evaluated at 20% and 50% densities. A novel approach was employed, incorporating specimens with single-, two-, and four-layer same pattern combinations, where subsequent layers were rotated 180 degrees to enhance interlayer bonding. Results demonstrated significant improvements in both tensile (up to 64%) and compressive strength (up to 47%) for two-layer structures compared to single-layer counterparts. The findings provide valuable insights into optimizing infill design and layer configurations for improved tensile and compressive strength and material efficiency in 3D-printed structures. This research highlights the potential for optimizing 3D-printed part performance through strategic multi-layer infill design, offering a pathway toward reduced material consumption and enhanced mechanical properties in additive manufacturing.

Keywords: 3D-printing; Additive manufacturing; Combined infill patterns; Fused deposition modeling (FDM); Infill structure; Polylactic acid; Polymer.

Fig. 1

1st category samples at 20%&50% infill density (single layer).

Fig. 2

Combined layer samples in a similar pattern (two layers)(SolidWorks 2023) (a) Two layers sample: front and back views (b) Two layers sample: rotation of the second layer 180° relative to the first layer (c) Configuration of two layers sample (Final sample) (d) Combined samples with 20% infill density (e) Combined samples with 50% infill density.

Fig. 3

Similar pattern combination samples (4 Layers) (SolidWorks 2023) (a) Four Layers of the same pattern (b) Rotation of second layer 180 (c) Rotation of fourth layer 180° (d) Building of four layers (Final sample).

Fig. 4

Printed Tensile Test Specimens (a) First-category specimens in 20% &50% infill (b) Second-category specimens in 20% infill (c) Second-category specimens in 50% infill.

Fig. 5

Printed Compression Test Specimen a) First category samples for 20% &50% b) Second & third category samples for 20%& 50% infill.

Fig. 6

Tensile strength behavior of the three categories of specimens.

Fig. 7

Comparison of tensile strength of three categories prepared specimens (a) 20% infill density (b) 50% infill density.

Fig. 8

Compressive strength behavior of the three categories specimens.

Fig. 9

Comparison of compressive strength of three categories prepared specimens (a) 20% infill density (b) 50% infill density.

Fig. 10

Taguchi optimization for the 20% infill density patterns.

Fig. 11

Taguchi optimization for the 50% infill density patterns.

Fig. 12

Honeycomb fitting plot for tensile and compression strength.

Fig. 13

Grid fitting plot for tensile and compression strength.

Fig. 14

Triangular fitting plot for tensile and compression strength.