scholarly journals Mechanical Properties of 3D-Printing Polylactic Acid Parts subjected to Bending Stress and Fatigue Testing

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3859 ◽  
Author(s):  
J. Antonio Travieso-Rodriguez ◽  
Ramon Jerez-Mesa ◽  
Jordi Llumà ◽  
Oriol Traver-Ramos ◽  
Giovanni Gomez-Gras ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Fatigue Testing ◽  
Fused Filament Fabrication ◽  
Layer Height ◽  
Four Point Bending ◽  
Layer Orientation ◽  
Rotating Bending ◽  
Flexural Resistance ◽  
Optimal Set

This paper aims to analyse the mechanical properties response of polylactic acid (PLA) parts manufactured through fused filament fabrication. The influence of six manufacturing factors (layer height, filament width, fill density, layer orientation, printing velocity, and infill pattern) on the flexural resistance of PLA specimens is studied through an L27 Taguchi experimental array. Different geometries were tested on a four-point bending machine and on a rotating bending machine. From the first experimental phase, an optimal set of parameters deriving in the highest flexural resistance was determined. The results show that layer orientation is the most influential parameter, followed by layer height, filament width, and printing velocity, whereas the fill density and infill pattern show no significant influence. Finally, the fatigue fracture behaviour is evaluated and compared with that of previous studies’ results, in order to present a comprehensive study of the mechanical properties of the material under different kind of solicitations.

scholarly journals Mechanical Properties of 3D-Printing Polylactic Acid Parts Subjected to Bending Stress and Fatigue Testing

2019 ◽  
Author(s):  
J. Antonio Travieso-Rodriguez ◽  
Ramon Jerez-Mesa ◽  
Jordi Llumà ◽  
Oriol Traver-Ramos ◽  
Giovanni Gomez-Gras ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Fatigue Testing ◽  
Fused Filament Fabrication ◽  
Layer Height ◽  
Four Point Bending ◽  
Layer Orientation ◽  
Rotating Bending ◽  
Flexural Resistance ◽  
Optimal Set

This paper aims to analyse the mechanical properties response of polylactic acid (PLA) parts manufactured through fused filament fabrication. The influence of six manufacturing factors (layer height, filament width, fill density, layer orientation, printing velocity, and infill pattern) on the flexural resistance of PLA specimens is studied through an L27 Taguchi experimental array. Different geometries have been tested on a four-point bending machine and on a rotating bending machine. From the first experimental phase, an optimal set of parameters deriving in the highest flexural resistance have been determined. Results show that layer orientation is the most influential parameter, followed by layer height, filament width, and printing velocity, whereas the fill density and infill pattern show no significant influence. Finally, the fatigue fracture behaviour is evaluated and compared with previous studies results, to present a comprehensive study of the mechanical properties of the material under different kind of solicitations.

scholarly journals Suitability of Recycled PLA Filament Application in Fused Filament Fabrication Process

2021 ◽  
Vol 15 (4) ◽  
pp. 491-497
Author(s):  
Tomislav Breški ◽  
Lukas Hentschel ◽  
Damir Godec ◽  
Ivica Đuretek
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Polylactic Acid ◽  
Design Of Experiment ◽  
Experimental Approach ◽  
Manufacturing Processes ◽  
Support Structures ◽  
Fused Filament Fabrication ◽  
Layer Height ◽  
Printing Parameters

Fused filament fabrication (FFF) is currently one of the most popular additive manufacturing processes due to its simplicity and low running and material costs. Support structures, which are necessary for overhanging surfaces during production, in most cases need to be manually removed and as such, they become waste material. In this paper, experimental approach is utilised in order to assess suitability of recycling support structures into recycled filament for FFF process. Mechanical properties of standardized specimens made from recycled polylactic acid (PLA) filament as well as influence of layer height and infill density on those properties were investigated. Optimal printing parameters for recycled PLA filaments are determined with Design of Experiment methods (DOE).

scholarly journals Evaluation of the influence of design in the mechanical properties of honeycomb cores used in composite panels

2021 ◽  
pp. 146442072098519
Author(s):  
A Miranda ◽  
M Leite ◽  
L Reis ◽  
E Copin ◽  
MF Vaz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Failure Modes ◽  
Industrial Applications ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Distribution Analysis ◽  
Absorbed Energy ◽  
Fused Filament Fabrication ◽  
Subtractive Manufacturing

The aerospace, automotive, and marine industries are heavily reliant on sandwich panels with cellular material cores. Although honeycombs with hexagonal cells are the most commonly used geometries as cores, recently there have been new alternatives in the design of lightweight structures. The present work aims to evaluate the mechanical properties of metallic and polymeric honeycomb structures, with configurations recently proposed and different in-plane orientations, produced by additive and subtractive manufacturing processes. Structures with configurations such as regular hexagonal honeycomb (Hr), lotus (Lt), and hexagonal honeycomb with Plateau borders (Pt), with 0°, 45°, and 90° orientations were analyzed. To evaluate its properties, three-point bending tests were performed, both experimentally and by numerical modeling, by means of the finite element method. Honeycombs of two aluminum alloys and polylactic acid were fabricated. The structures produced in aluminum were obtained either by selective laser melting technology or by machining, while polylactic acid structures were obtained by material extrusion using fused filament fabrication. From the stress distribution analysis and the load–displacement curves, it was possible to evaluate the strength, stiffness, and absorbed energy of the structures. Failure modes were also analyzed for polylactic acid honeycombs. In general, a strong correlation was observed between numerical and experimental results. The results show that the stiffness and absorbed energy increase in the order, Hr, Pt, Lt, and with the orientation through the sequence, 45°, 90°, 0°. Thus, Lt structures with 0° orientation seem to be good alternatives to the traditional honeycombs used in sandwich composite panels for those industrial applications where low weight, high stiffness, and large energy-absorbing capacity are required.

Temperature-compensated constitutive model of fused filament fabrication 3D printed PLA materials with full extrusion temperatures

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kaiyang Zhu ◽  
Zichen Deng ◽  
Shi Dai ◽  
Yajun Yu
Keyword(s):  
Mechanical Properties ◽  
Thermal Decomposition ◽  
Constitutive Model ◽  
Polylactic Acid ◽  
Extrusion Temperature ◽  
Fused Filament Fabrication ◽  
Printing Process ◽  
Content Type ◽  
3D Printed ◽  
Interlayer Bonding

Purpose This study aims to focus on the effect of interlayer bonding and thermal decomposition on the mechanical properties of fused filament fabrication-printed polylactic acid specimens at high extrusion temperatures. Design/methodology/approach A printing process, that is simultaneous manufacturing of contour and specimen, is used to improve the printing accuracy at high extrusion temperatures. The effects of the extrusion temperature on the mechanical properties of the interlayer and intra-layer are evaluated via tensile experiments. In addition, the microstructure evolution affected by the extrusion temperature is observed using scanning electron microscopy. Findings The results show that the extrusion temperature can effectively improve the interlayer bonding property; however, the mechanical properties of the specimen for extrusion temperatures higher than 270°C may worsen owing to the thermal decomposition of the polylactic acid (PLA) material. The optimum extrusion temperature of PLA material in the three-dimensional (3D) printing process is recommended to be 250–270°C. Originality/value A temperature-compensated constitutive model for 3D printed PLA material under different extrusion temperatures is proposed. The present work facilitates the prediction of the mechanical properties of specimens at an extrusion temperature for different printing temperatures and different layers.

scholarly journals The Mechanical Properties and Fatigue Prediction of a New Generation of Osteosynthesis Devices

2021 ◽  
Vol 71 (2) ◽  
pp. 101-108
Author(s):  
Drátovská Veronika ◽  
Sedláček Radek ◽  
Padovec Zdeněk ◽  
Růžička Pavel ◽  
Kratochvíl Adam
Keyword(s):  
Mechanical Properties ◽  
Fatigue Testing ◽  
Measured Data ◽  
Bone Plates ◽  
Bending Fatigue ◽  
Material Parameters ◽  
Four Point Bending ◽  
Surgical Implants ◽  
Two Generations ◽  
New Generation

Abstract The aim of the study was to predict the fatigue life of metallic bone plates employing SIMULIA fe-safe software. Two materials commonly used for surgical implants were subjected to investigation: 1.4441 (ASTM F138) stainless steel for implants and Ti6Al4V ELI (ASTM F136) titanium alloy. The material parameters of the two materials were determined from experimental research. Four-point bending fatigue testing was conducted on two generations of bone plates in order to allow for the comparison of the prediction results with the measured data from the experiments.

scholarly journals Effect of Porosity and Crystallinity on 3D Printed PLA Properties

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1487 ◽  
Author(s):  
Yuhan Liao ◽  
Chang Liu ◽  
Bartolomeo Coppola ◽  
Giuseppina Barra ◽  
Luciano Di Maio ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Polylactic Acid ◽  
Complex Geometry ◽  
Fused Filament Fabrication ◽  
3D Printed ◽  
Physical Changes ◽  
Crystalline Forms

Additive manufacturing (AM) is a promising technology for the rapid tooling and fabrication of complex geometry components. Among all AM techniques, fused filament fabrication (FFF) is the most widely used technique for polymers. However, the consistency and properties control of the FFF product remains a challenging issue. This study aims to investigate physical changes during the 3D printing of polylactic acid (PLA). The correlations between the porosity, crystallinity and mechanical properties of the printed parts were studied. Moreover, the effects of the build-platform temperature were investigated. The experimental results confirmed the anisotropy of printed objects due to the occurrence of orientation phenomena during the filament deposition and the formation both of ordered and disordered crystalline forms (α and δ, respectively). A heat treatment post-3D printing was proposed as an effective method to improve mechanical properties by optimizing the crystallinity (transforming the δ form into the α one) and overcoming the anisotropy of the 3D printed object.

scholarly journals Comparative Study of Tensile Properties between Fused Filament Fabricated and Injection-Molded Wood-PLA Composite Parts

2020 ◽  
Author(s):  
M. Damous Zandi ◽  
Ramon Jerez-Mesa ◽  
Jordi Llumà ◽  
Jordi Jorba-Peiro ◽  
J. Antonio Travieso-Rodriguez
Keyword(s):  
Tensile Properties ◽  
Wood Fibers ◽  
Fused Filament Fabrication ◽  
Axis Orientation ◽  
Layer Height ◽  
Maximum Tension ◽  
Injection Molded ◽  
Optimal Set ◽  
Printing Parameters ◽  
Manufacturing Parameters

The present study evaluates the manufacturing parameters effects on the tensile properties of material composed by polylactic acid (PLA) with wood fibers known as Timberfill. The specimens were built through fused filament fabrication (FFF). The influence of four printing parameters (Layer height, Fill density, Printing velocity, and Orientation) are considered through a L27 Taguchi orthogonal array in order to reduce experimental runs. Tensile test is applied to obtain the response variable used as output results to perform the ANOVA calculations. Fill density is the most influential parameter on the tensile strength, followed by building orientation and layer height, whereas the printing velocity shows no significant influence. The optimal set of parameters and levels is found, being 75% fill density, 0○Z-axis orientation, 0.4 mm layer height, and 40 mm/s velocity as the best combination. Applying this combination showed 9.37 MPa in maximum tension. Lastly, five solid Timberfill specimens manufactured via injection molding technology were also tested and the results compared to the printed samples. The values of the elastic modulus, elastic limit, and maximum tension of the injected samples were almost twofold of those were obtained for the FFF samples, but the maximum elongation of injected specimens was fell sharply.

scholarly journals Digital volume correlation analysis of polylactic acid based fused filament fabrication printed composites

2021 ◽  
pp. 002199832110205
Author(s):  
Cristofaro S Timpano ◽  
Garrett W Melenka
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Measurement Techniques ◽  
Strain Tensor ◽  
Uniaxial Tensile ◽  
Digital Volume Correlation ◽  
Tensor Fields ◽  
Fused Filament Fabrication ◽  
Study Results ◽  
Anisotropic Mechanical Properties

Fused filament fabrication (FFF) has rapidly begun to see implementation in industrial fields as a method of rapid manufacturing. Traditional FFF parts are made from a single thermoplastic polymer. The polymer is heated to its melting point and deposited on a work bed where a model is gradually built from the base up. While traditional FFF parts have low mechanical properties, a reinforcing phase allows for improved mechanical properties. The addition of a reinforcing material to the base polymer and complex internal microstructure of the 3 D printed party leads to anisotropic mechanical properties. Thus, these materials’ mechanical properties become challenging to characterize using traditional measurement techniques due to the previously mentioned factors. Therefore, it is essential to develop a method in which mechanical properties can be measured and analyzed. This study aims to characterize the mechanical behaviour under a uniaxial tensile load of an FFF produced polylactic acid (PLA)-copper particulate composite. The internal response of the FFF sample was imaged using micro-computed tomography at predetermined loads. The μ-CT images were input into an open-source digital volume correlation (DVC) software to measure the internal displacements and strain tensor fields. The study results show the development of different strain fields and interior features of the FFF parts.

scholarly journals Evaluation of the Infill Design on the Tensile Response of 3D Printed Polylactic Acid Polymer

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2195
Author(s):  
Tanner David Harpool ◽  
Ibrahim Mohammed Alarifi ◽  
Basheer A. Alshammari ◽  
Abdul Aabid ◽  
Muneer Baig ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Stress ◽  
Polylactic Acid ◽  
Solid Substrate ◽  
Ultimate Tensile Stress ◽  
Experimental Results ◽  
Fused Filament Fabrication ◽  
Element Analysis ◽  
Cross Sectional ◽  
3D Printed

The current study explores the effects of geometrical shapes of the infills on the 3D printed polylactic acid (PLA) plastic on the tensile properties. For this purpose, by utilizing an accessible supply desktop printer, specimens of diamond, rectangular, and hexagonal infill patterns were produced using the fused filament fabrication (FFF) 3D printing technique. Additionally, solid samples were printed for comparison. The printed tensile test specimens were conducted at environmental temperature, Ta of 23 °C and crosshead speed, VC.H of 5 mm/min. Mainly, this study focuses on investigating the percentage infill with respect to the cross-sectional area of the investigated samples. The mechanical properties, i.e., modulus of toughness, ultimate tensile stress, yield stress, and percent elongation, were explored for each sample having a different geometrical infill design. The test outcomes for each pattern were systematically compared. To further validate the experimental results, a computer simulation using finite element analysis was also performed and contrasted with the experimental tensile tests. The experimental results mainly suggested a brittle behavior for solidly infilled specimen, while rectangular, diamond, and hexagonal infill patterns showed ductile-like behavior (fine size and texture of infills). This brittleness may be due to the relatively higher infill density results that led to the high bonding adhesion of the printed layers, and the size and thickness effects of the solid substrate. It made the solidly infilled specimen structure denser and brittle. Among all structures, hexagon geometrical infill showed relative improvement in the mechanical properties (highest ultimate tensile stress and modulus values 1759.4 MPa and 57.74 MPa, respectively) compared with other geometrical infills. Therefore, the geometrical infill effects play an important role in selecting the suitable mechanical property’s values in industrial applications.

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