In order to optimize the efficiency of the Fused deposition modeling (FDM) process, this study used polylactic acid (PLA) material under different parameters (the printing angle and the raster angle) to fabricate specimens and to explore its tensile properties. The effect of the ultraviolet (UV) curing process on PLA materials was also investigated. The results showed that the printing and raster angles have a high impact on the tensile properties of PLA materials. The UV curing process enhanced the brittleness and reduced the elongation of PLA material. Different effects were observed on tensile strength and modulus of specimens printed with different parameters after UV curing. The above results will be a great help for researchers who are working to achieve sustainability of PLA materials and FDM technology.

https://www.mdpi.com/2073-4360/13/14/2387/pdf

Effect of Printing Parameters on the Tensile Properties of 3D-Printed Polylactic Acid (PLA) Based on Fused Deposition Modeling

Polylactic acid (PLA) is produced from renewable materials, has a low melting temperature and has a low carbon footprint. These advantages have led to the extensive use of polylactic acid in additive manufacturing, particularly by fused filament fabrication (FFF). PLA parts that are 3D printed for industrial applications require stable mechanical properties and predictability regarding their dependence on the process parameters. Therefore, the development of the FFF process has been continuously accompanied by the development of software packages that generate CNC codes for the printers. A large number of user-controllable process parameters have been introduced in these software packages. In this respect, a lot of articles in the specialized literature address the issue of the influence of the process parameters on the mechanical properties of 3D-printed specimens. A systematic review of the research targeting the influence of process parameters on the mechanical properties of PLA specimens additively manufactured by fused filament fabrication was carried out by the authors of this paper. Six process parameters (layer thickness, printing speed, printing temperature, build plate temperature, build orientation and raster angle) were followed. The mechanical behavior was evaluated by tensile, compressive and bending properties.

/pdf/the-influence-of-the-process-parameters-on-the-mechanical-3b0xsg09.pdf

The Influence of the Process Parameters on the Mechanical Properties of PLA Specimens Produced by Fused Filament Fabrication—A Review

Although the literature is abundant with the experimental methods to characterize mechanical behavior of parts made by fused filament fabrication 3D printing, less attention has been paid in using computational models to predict the mechanical properties of these parts. In the present paper, a numerical homogenization technique is developed to predict the effect of printing process parameters on the elastic response of 3D printed parts with cellular lattice structures. The development of finite element computational models of printed parts is based on a multi scale approach. Initially, at the micro scale level, the analysis of micro-mechanical models of a representative volume element is used to calculate the effective orthotropic properties. The finite element models include different infill densities and building/raster orientation maintaining the bonded region between the adjacent fibers and layers. The elastic constants obtained by this method are then used as an input for the creation of macro scale finite element models enabling the simulation of the mechanical response of printed samples subjected to the bending, shear, and tensile loads. Finally, the results obtained by the homogenization technique are validated against more realistic finite element explicit microstructural models and experimental measurements. The results show that, providing an accurate characterization of the properties to be fed into the macro scale model, the use of the homogenization technique is a reliable tool to predict the elastic response of 3D printed parts. The outlined approach provides faster iterative design of 3D printed parts, contributing to reducing the number of experimental replicates and fabrication costs.

/pdf/investigation-of-the-effect-of-raster-angle-build-4cciph7n2i.pdf

Investigation of the effect of raster angle, build orientation, and infill density on the elastic response of 3D printed parts using finite element microstructural modeling and homogenization techniques

Eliminating voids and reducing mechanical anisotropy in fused filament fabrication parts by adjusting the filament extrusion rate

Tailoring of advanced poly(lactic acid)‐based materials: A review

3D printing by fused filament fabrication (FFF) provides an innovative manufacturing method for complex geometry components. Since FFF is a layered manufacturing process, effects of process parameters are of concern when plastic materials such as polylactic acid (PLA), polystyrene and nylon are used. This study explores how the process parameters, e.g. build orientation and infill pattern/density, affect the mechanical response of PLA samples produced using FFF. Digital image correlation (DIC) was employed to get full-field surface-strain measurements. The results show the influence of build orientation and infill density is significant. For on-edge orientation, the tensile strength and Young’s modulus were 55 MPa and 3.5 GPa respectively, which were about 91% and 40% less for the upright orientation, demonstrating a significant anisotropy. The tensile strength and Young’s modulus increased with increasing infill density. In contrast, different infill patterns have no significant effect. Considering the influence of build orientation, based on the experimental results, a constitutive model derived from the laminate plate theory was employed. The material parameters were determined by tensile tests. Results demonstrated a reasonable agreement between the experimental data and the predictive model. Similar anisotropy to tension was observed in shear tests; shear modulus and shear strength for 45° flat orientation were about 1.55 GPa and 36 MPa, whereas for upright specimens they were about 0.95 GPa and 18 MPa, respectively. The findings provide a framework for systematic mechanical characterisation of 3D-printed polymers and potential ways of choosing process parameters to maximise performance for a given design.

/pdf/the-effect-of-processing-parameters-on-the-mechanical-a8ye7g58rh.pdf

The effect of processing parameters on the mechanical characteristics of PLA produced by a 3D FFF printer

Glass fibre reinforced polymer composites are frequently used in marine applications where the combined effects of cyclic loads and the seawater environment limit their fatigue life. This paper aims to demonstrate the degradation that seawater causes to the stiffness of the composites. Three-point bending fatigue properties of cross-ply woven glass fibre composites commonly used to manufacture tidal turbine blades are reported for both wet and dry conditions. Failure analysis based on the Digital Image Correlation method was performed to identify damaged zones on the test coupon surface and to follow failure progression during the fatigue tests. To characterize the damage in the composite, stiffness degradation has been monitored during the entire fatigue history. Scanning electron microscopy was used to identify multiple failure mechanisms on the specimen fracture surface. In addition, for further verification of microscopy results, X-Ray Micro-computed tomography, was used to characterize the internal damage such as delamination. From the full-field strain measurement technique and microscopic examination of failed samples, it was found that distributed localized strains are evidence of the number of resin cracks and de-bonded areas. SEM examination shows a degraded fibre/matrix interface region due to the action of seawater.

/pdf/fatigue-damage-analysis-of-gfrp-composites-using-digital-3y7nfqfbp1.pdf

Fatigue damage analysis of GFRP composites using digital image correlation

Structural performance of composite tidal turbine blades

Designing highly stressed offshore renewable energy composite structures (e.g. wind and tidal turbine blades) necessitates characterisation of woven fabric composite under off axial loading. In thi...

https://journals.sagepub.com/doi/pdf/10.1177/00219983211054232

Investigation of anisotropy effects in glass fibre reinforced polymer composites on tensile and shear properties using full field strain measurement and finite element multi-scale techniques:

Hassan Gonabadi

Papers

The effect of processing parameters on the mechanical characteristics of PLA produced by a 3D FFF printer

Investigation of the effect of raster angle, build orientation, and infill density on the elastic response of 3D printed parts using finite element microstructural modeling and homogenization techniques

Fatigue damage analysis of GFRP composites using digital image correlation

Structural performance of composite tidal turbine blades

Investigation of anisotropy effects in glass fibre reinforced polymer composites on tensile and shear properties using full field strain measurement and finite element multi-scale techniques: