Mechanical Properties of Direct Waste Printing of Polylactic Acid with Universal Pellets Extruder: Comparison to Fused Filament Fabrication on Open-Source Desktop Three-Dimensional Printers

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.

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Suitability of Recycled PLA Filament Application in Fused Filament Fabrication Process

Tehnički glasnik ◽

10.31803/tg-20210805120621 ◽

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).

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

Rapid Prototyping Journal ◽

10.1108/rpj-04-2021-0101 ◽

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.

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Fused filament fabrication of continuous optic fiber reinforced polylactic acid composites

Rapid Prototyping Journal ◽

10.1108/rpj-06-2021-0145 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Rui Yan ◽

Yuye Wang ◽

Pengjun Luo ◽

Yangbo Li ◽

Xiaochun Lu

Keyword(s):

Polylactic Acid ◽

Three Dimensional ◽

Underlying Mechanism ◽

Uniaxial Tensile ◽

Optic Fiber ◽

Fiber Reinforced ◽

Fused Filament Fabrication ◽

Engineering Applications ◽

Content Type ◽

Axial Tensile

Purpose The limited strength of polylactic acid (PLA) hinders its extensive engineering applications. This paper aims to enhance its strength and realize diverse applications. Design/methodology/approach Here, the continuous fiber reinforced PLA composites are fabricated by a customized fused filament fabrication three-dimensional printer. Uniaxial tensile and three-point flexural tests have been conducted to analyze the reinforcement effect of the proposed composites. To unveil the adhering mechanism of optic fiber (OF) and PLA, post failure analysis including the micro imaging and morphology have been performed. The underlying mechanism is that the axial tensile strength of the OF and the interfacial adhesion between PLA and OF compete to enhance the mechanical properties of the composite. Findings It is found that 10%–20% enhancement of strength, ductility and toughness due to the incorporation of the continuous OF. Originality/value The continuous OFs are put into PLA first time to improve the strength. The fabrication method and process reported here are potentially applied in such engineering applications as aerospace, defense, auto, medicine, etc.

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

Materials ◽

10.3390/ma12233859 ◽

2019 ◽

Vol 12 (23) ◽

pp. 3859 ◽

Cited By ~ 7

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.

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

10.20944/preprints201910.0293.v1 ◽

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.

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Effect of Porosity and Crystallinity on 3D Printed PLA Properties

Polymers ◽

10.3390/polym11091487 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1487 ◽

Cited By ~ 19

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.

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Property Enhancement of Carbon Fiber-Reinforced Polylactic Acid Composites Prepared by Fused-Deposition Modeling

Advances in Computer and Electrical Engineering - Handbook of Research on Recent Developments in Electrical and Mechanical Engineering ◽

10.4018/978-1-7998-0117-7.ch017 ◽

2020 ◽

pp. 455-478

Author(s):

Pravin R. Kubade ◽

Hrushikesh B. Kulkarni ◽

Vinayak C. Gavali

Keyword(s):

Mechanical Properties ◽

Additive Manufacturing ◽

Carbon Fiber ◽

Polylactic Acid ◽

Fused Deposition Modeling ◽

Three Dimensional ◽

Fiber Reinforced ◽

Fused Deposition ◽

Deposition Modeling ◽

Properties Of Composites

Additive Manufacturing or three-dimensional printing refers to a process of building lighter, stronger three-dimensional parts, manufactured layer by layer. Additive manufacturing uses a computer and CAD software which passes the program to the printer to build the desired shape. Metals, thermoplastic polymers, and ceramics are the preferred materials used for additive manufacturing. Fused deposition modeling is one additive manufacturing technique involving the use of thermoplastic polymer for creating desired shape. Carbon fibers can be added into polymer to strengthen the composite without adding additional weight. Present work deals with the manufacturing of Carbon fiber-reinforced Polylactic Acid composites prepared using fused deposition modeling. Mechanical and thermo-mechanical properties of composites are studied as per ASTM standards and using sophisticated instruments. It is observed that there is enhancement in thermo-mechanical properties of composites due to addition reinforcement which is discussed in detail.

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Mechanical Properties of 3D-Printed Acrylonitrile–Butadiene–Styrene TiO2 and ATO Nanocomposites

Polymers ◽

10.3390/polym12071589 ◽

2020 ◽

Vol 12 (7) ◽

pp. 1589 ◽

Cited By ~ 2

Author(s):

Nectarios Vidakis ◽

Markos Petousis ◽

Athena Maniadi ◽

Emmanuel Koudoumas ◽

Marco Liebscher ◽

...

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Sno2 Nanoparticles ◽

Three Dimensional ◽

Acrylonitrile Butadiene Styrene ◽

International Standards ◽

Fused Filament Fabrication ◽

Melt Mixing ◽

3D Printed ◽

Butadiene Styrene

In order to enhance the mechanical performance of three-dimensional (3D) printed structures fabricated via commercially available fused filament fabrication (FFF) 3D printers, novel nanocomposite filaments were produced herein following a melt mixing process, and further 3D printed and characterized. Titanium Dioxide (TiO2) and Antimony (Sb) doped Tin Oxide (SnO2) nanoparticles (NPs), hereafter denoted as ATO, were selected as fillers for a polymeric acrylonitrile butadiene styrene (ABS) thermoplastic matrix at various weight % (wt%) concentrations. Tensile and flexural test specimens were 3D printed, according to international standards. It was proven that TiO2 filler enhanced the overall tensile strength by 7%, the flexure strength by 12%, and the micro-hardness by 6%, while for the ATO filler, the corresponding values were 9%, 13%, and 6% respectively, compared to unfilled ABS. Atomic force microscopy (AFM) revealed the size of TiO2 (40 ± 10 nm) and ATO (52 ± 11 nm) NPs. Raman spectroscopy was performed for the TiO2 and ATO NPs as well as for the 3D printed nanocomposites to verify the polymer structure and the incorporated TiO2 and ATO nanocrystallites in the polymer matrix. The scope of this work was to fabricate novel nanocomposite filaments using commercially available materials with enhanced overall mechanical properties that industry can benefit from.

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

Journal of Composite Materials ◽

10.1177/00219983211020500 ◽

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.

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