This study investigates the effects of process parameters on the quality of products fabricated by fused deposition modeling (FDM), such as surface roughness and tensile strength. Polylactic acid (PLA) samples were built on a FDM machine at various layer thicknesses, nozzle temperature and deposition head velocity. The effect of cooling the samples during the process was also considered. The experimental study was performed according to a mixed type Taguchi L16 orthogonal array. The effectiveness of each parameter was also discussed by an analysis of variance (ANOVA). The tensile strength results were compatible with the optical images of the fracture surfaces while the surface roughness results were compatible with the surface topography of the parts along the thickness. The two dominant quality characteristics were found to be layer thickness and deposition head velocity. Lower layer thickness values yielded higher tensile strength and lower surface roughness. Use of a cooling fan and nozzle temperature were found to be the least effective parameters. Finally, the results indicated that tensile strength and surface quality of the FDM samples improved about 25 %, and 12 %, respectively at optimal process conditions.

One of the important process parameters affecting the tensile strength and build time of the part is the build orientation. Therefore, in this study, FDM 3D-printed PLA parts were fabricated at different build orientations to examine the effects of build orientation on the tensile properties and build time of material. In this regard, three build orientations and three print angles were examined. According to results, tensile strength decreased when the build orientation of the parts was aligned from flat to upright direction and 0° to 90° printing angle. For upright build orientation, 36% less tensile strength obtained than the flat ones because of the fracture mode and the loading direction. In terms of build time, build time increased as the build orientation changed from flat to upright. Therefore, the build orientation had a big impact on the tensile properties and build time of the parts produced using FDM. The findings of this study will contribute to the literature on proper build orientations and print angles.

The purpose of this study is to analyze the effect of the infill pattern on the mechanical properties of 3D printed PLA parts. Polylactic acid (PLA) parts were fabricated by fused deposition modeling (FDM) at various infill patterns at 30% infill density. Five different infill patterns (stars, 3D honeycomb, honeycomb, gyroid, Hilbert curve) have been investigated. The results have shown that the honeycomb infill pattern exhibited the highest mechanical properties with 29.43 MPa and 2.04 mm elongation due to the improved strength of the strut junctions in this pattern. In the case of the Hilbert curve pattern, compared to the other patterns, though they have the same infill density, tensile strength was lowest because of the presence of large air gaps in the pattern that induced rapid fracture during the test. The optical microscope images of the fracture surfaces were compatible with the tensile strength results. Also considering the build time and the spent filament, it can be said that the honeycomb infill pattern is very promising. Lastly, the results showed that the tensile strength and elongation of 3D printed PLA parts increased 43.4% and 32%, respectively, under optimum infill pattern conditions. The findings of this study will help manufacturing firms and researchers to decide on the appropriate infill pattern, so that FDM parts can be fabricated with minimal production cost and good mechanical properties.

Spinal fusion cages play a crucial role in stabilizing the spine and promoting bone growth in degenerative spine disorders. Recent advancements in biodegradable polymer‐based cages have introduced materials with shape memory properties, enabling minimally invasive implantation and improved adaptability. This study focuses on the development of 4D‐printed PLA/PCL blend spinal cages, investigating their thermal, mechanical, biodegradation, and shape memory properties, alongside surface wettability through contact angle measurements. The novelty of this study lies in identifying the optimal PLA/PCL ratio, balancing mechanical strength, biodegradability, and shape memory behavior for spinal fusion applications. The findings highlight PLA/PCL (80:20) as the most suitable composition, offering a well‐balanced combination of properties. Differential scanning calorimetry (DSC) analysis revealed that 20 wt% PCL enhances toughness, flexibility, and crystallinity while slightly reducing the glass transition temperature. Mechanical testing showed improved fracture behavior and elongation at this ratio, with tensile stress peaking before decreasing at higher PCL concentrations due to increased ductility. Biodegradation studies confirmed an increasing degradation rate with higher PCL content, while contact angle measurements indicated greater hydrophilicity, though this trend reversed at higher concentrations. Shape memory analysis demonstrated that as PCL content increased from 10 to 60 wt%, shape recovery decreased from 76.07% to 61.28%, while high shape fixity (96.42%–99.80%) was maintained. The PLA/PCL20 blend exhibited a 74.5% shape memory effect and a 68.75% recovery rate in the spinal cage design, making it a promising material for minimally invasive spinal fusion applications.