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.

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.

Stiffness prediction of 3D printed fiber-reinforced thermoplastic composites

2019 ◽  
Vol 26 (3) ◽  
pp. 549-555
Author(s):  
Jin Young Choi ◽  
Mark Timothy Kortschot
Keyword(s):  
Mechanical Properties ◽  
Extrusion Direction ◽  
Analytical Models ◽  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Flat Plates ◽  
Fused Filament Fabrication ◽  
Element Analysis ◽  
Content Type ◽  
3D Printed

Purpose The purpose of this study is to confirm that the stiffness of fused filament fabrication (FFF) three-dimensionally (3D) printed fiber-reinforced thermoplastic (FRP) materials can be predicted using classical laminate theory (CLT), and to subsequently use the model to demonstrate its potential to improve the mechanical properties of FFF 3D printed parts intended for load-bearing applications. Design/methodology/approach The porosity and the fiber orientation in specimens printed with carbon fiber reinforced filament were calculated from micro-computed tomography (µCT) images. The infill portion of the sample was modeled using CLT, while the perimeter contour portion was modeled with a rule of mixtures (ROM) approach. Findings The µCT scan images showed that a low porosity of 0.7 ± 0.1% was achieved, and the fibers were highly oriented in the filament extrusion direction. CLT and ROM were effective analytical models to predict the elastic modulus and Poisson’s ratio of FFF 3D printed FRP laminates. Research limitations/implications In this study, the CLT model was only used to predict the properties of flat plates. Once the in-plane properties are known, however, they can be used in a finite element analysis to predict the behavior of plate and shell structures. Practical implications By controlling the raster orientation, the mechanical properties of a FFF part can be optimized for the intended application. Originality/value Before this study, CLT had not been validated for FFF 3D printed FRPs. CLT can be used to help designers tailor the raster pattern of each layer for specific stiffness requirements.

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.

Fused Filament Fabrication 3D Printed Polylactic Acid Electroosmotic Pumps

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Liang Wu ◽  
Stephen Beirne ◽  
Joan-Marc Cabot Canyelles ◽  
Brett Paull ◽  
Gordon G. Wallace ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Polylactic Acid ◽  
Fused Filament Fabrication ◽  
Flexible Approach ◽  
Electroosmotic Pump ◽  
3D Printed ◽  
Electroosmotic Pumps

Additive manufacturing (3D printing) offers a flexible approach for the production of bespoke microfluidic structures such as the electroosmotic pump. Here a readily accessible fused filament fabrication (FFF) 3D printing...

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.

Effect of Polyvinyl Alcohol Concentration on the Mechanical Properties of Collagen/Polyvinyl Alcohol Blends

2015 ◽  
Vol 732 ◽  
pp. 161-164 ◽  
Author(s):  
Jan Vesely ◽  
Lukas Horny ◽  
Hynek Chlup ◽  
Milos Beran ◽  
Milan Krajicek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Stress ◽  
Polyvinyl Alcohol ◽  
Modulus Of Elasticity ◽  
Tensile Tests ◽  
Ultimate Tensile Stress ◽  
Alcohol Concentration ◽  
Uniaxial Tensile ◽  
Initial Modulus ◽  
Water Saturated

The effects of the polyvinyl alcohol (PVA) concentration on mechanical properties of hydrogels based on blends of native or denatured collagen / PVA were examined. Blends of PVA with collagen were obtained by mixing the solutions in different ratios, using glycerol as a plasticizer. The solutions were cast on polystyrene plates and the solvent was allowed to evaporate at room temperature. Uniaxial tensile tests were performed in order to obtain the initial modulus of elasticity (up to deformation 0.1), the ultimate tensile stress and the deformation at failure of the material in the water-saturated hydrogel form. It was found that the material was elastic and the addition of PVA helped to enhance both the ultimate tensile stress and modulus of elasticity of the films. Samples prepared from denaturated collagen showed the higher ultimate tensile stress and the deformation at failure in comparison with those prepared from native collagen. The results suggest that we could expect successful application of the collagen/PVA biomaterial for tissue engineering.

Effect of heat treatment on mechanical properties of 3D printed polylactic acid parts

2021 ◽  
Vol 63 (1) ◽  
pp. 73-78
Author(s):  
Pulkin Gupta ◽  
Sudha Kumari ◽  
Abhishek Gupta ◽  
Ankit Kumar Sinha ◽  
Prashant Jindal
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Polylactic Acid ◽  
Recrystallization Temperature ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Dog Bone ◽  
Heat Treated ◽  
Maximum Decrease ◽  
3D Printed

Abstract Fused deposition modelling (FDM) is a layer-by-layer manufacturing process type of 3D-printing (3DP). Significant variation in the mechanical properties of 3D printed specimens is observed because of varied process parameters and interfacial bonding between consecutive layers. This study investigates the influence of heat treatment on the mechanical strength of FDM 3D printed Polylactic acid (PLA) parts with constant 3DP parameters and ambient conditions. To meet the objectives, 7 sets, each containing 5 dog-bone shaped samples, were fabricated from commercially available PLA filament. Each set was subjected to heat treatment at a particular temperature for 1 h and cooled in the furnace itself, while one set was left un-treated. The temperature for heat treatment (Th) varied from 30 °C to 130 °C with increments of 10 °C. The heat-treated samples were characterized under tensile loading of 400 N and mechanical properties like Young’s modulus (E), Strain % ( ε ) and Stiffness (k) were evaluated. On comparing the mechanical properties of heat-treated samples to un-treated samples, significant improvements were observed. Heat treatment also altered the geometries of the samples. Mechanical properties improved by 4.88 % to 10.26 % with the maximum being at Th of 110 °C and below recrystallization temperature (Tr) of 65 °C. Deformations also decreased significantly at higher temperatures above 100 °C, by a maximum of 36.06 %. The dimensions of samples showed a maximum decrease of 1.08 % in Tr range and a maximum decrease of 0.31 % in weight at the same temperature. This study aims to benefit the society by establishing suitable Th to recover the lost strength in PLA based FDM 3D printed parts.

Mechanical Properties of 3D-Printed Wood-Plastic Composites

2018 ◽  
Vol 777 ◽  
pp. 499-507 ◽  
Author(s):  
Ossi Martikka ◽  
Timo Kärki ◽  
Qing Ling Wu
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
3D Printing ◽  
Impact Strength ◽  
Polylactic Acid ◽  
Wood Plastic Composite ◽  
Wood Plastic Composites ◽  
Plastic Composite ◽  
Plastic Composites ◽  
3D Printed

3D printing has rapidly become popular in both industry and private use. Especially fused deposition modeling has increased its popularity due to its relatively low cost. The purpose of this study is to increase knowledge in the mechanical properties of parts made of wood-plastic composite materials by using 3D printing. The tensile properties and impact strength of two 3D-printed commercial wood-plastic composite materials are studied and compared to those made of pure polylactic acid. Relative to weight –mechanical properties and the effect of the amount of fill on the properties are also determined. The results indicate that parts made of wood-plastic composites have notably lower tensile strength and impact strength that those made of pure polylactic acid. The mechanical properties can be considered sufficient for low-stress applications, such as visualization of prototypes and models or decorative items.

scholarly journals Experimental Investigation into the Effect of Surface Roughness and Mechanical Properties of 3D-Printed Titanium Ti-64 ELI after Heat Treatment

2021 ◽  
Author(s):  
Lebogang Lebea ◽  
Harry M Ngwangwa ◽  
Dawood Desai ◽  
Fuluphelo Nemavhola
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Dental Implants ◽  
Dental Implant ◽  
Complex Geometry ◽  
Poor Performance ◽  
Vital Role ◽  
Ultimate Tensile Stress ◽  
3D Printed ◽  
Effect Of Surface

The initial stability after implantology is paramount to the survival of the dental implant and the surface roughness of the implant plays a vital role in this regard. The characterisation of surface topography is a complicated branch of metrology, with a huge range of parameters available. Each parameter contributes significantly towards the survival and mechanical properties of 3D-printed specimens. The purpose of this paper is to experimentally investigate the effect of surface roughness of 3D-printed dental implants and 3D-printed dogbone tensile samples under areal height (Ra) parameters, amplitude parameters (average of ordinates), skewness (Rsk) parameters and mechanical properties. During the experiment, roughness values were analysed and the results showed that the skewness parameter demonstrated a minimum value of 0.596%. The 3D-printed dental implant recorded Ra with a 3.4 mm diameter at 43.23% and the 3D-printed dental implant with a 4.3 mm diameter at 26.18%. Samples with a complex geometry exhibited a higher roughness surface, which was the greatest difficulty of additive manufacturing when evaluating surface finish. The results show that when the ultimate tensile stress (UTS) decreases from 968.35 MPa to 955.25 MPa, Ra increases by 1.4% and when UTS increases to 961.18 MPa, Ra increases by 0.6%. When the cycle decreases from 262142 to 137433, Ra shows that less than a 90.74% increase in cycle is obtained. For 3D-printed dental implants, the higher the surface roughness, the lower the mechanical properties, ultimately leading to decreased implant life and poor performance.

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