Enhancing Mechanical Properties of Polymer 3D Printed Parts

Parts made from thermoplastic polymers fabricated through 3D printing have reduced mechanical properties compared to those fabricated through injection molding. This paper analyzes a post-processing heat treatment aimed at enhancing mechanical properties of 3D printed parts, in order to reduce the difference mentioned above and thus increase their applicability in functional applications. Polyethylene Terephthalate Glycol (PETG) polymer is used to 3D print test parts with 100% infill. After printing, samples are packed in sodium chloride powder and then heat treated at a temperature of 220 °C for 5 to 15 min. During heat treatment, the powder acts as support, preventing deformation of the parts. Results of destructive testing experiments show a significant increase in tensile and compressive strength following heat treatment. Treated parts 3D printed in vertical orientation, usually the weakest, display 143% higher tensile strength compared to a control group, surpassing the tensile strength of untreated parts printed in horizontal orientation—usually the strongest. Furthermore, compressive strength increases by 50% following heat treatment compared to control group. SEM analysis reveals improved internal structure after heat treatment. These results show that the investigated heat treatment increases mechanical characteristics of 3D printed PETG parts, without the downside of severe part deformation, thus reducing the performance gap between 3D printing and injection molding when using common polymers.

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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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Mechanical properties comparison of PLA, tough PLA and PC 3D printed materials with infill structure – Influence of infill pattern on tensile mechanical properties

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1208/1/012019 ◽

2021 ◽

Vol 1208 (1) ◽

pp. 012019

Author(s):

Adi Pandzic ◽

Damir Hodzic

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Elastic Modulus ◽

3D Printing ◽

Material Testing ◽

Fused Deposition Modelling ◽

Fused Deposition ◽

3D Printed ◽

Printed Materials ◽

Product Weight

Abstract One of the advantages provided by fused deposition modelling (FDM) 3D printing technology is the manufacturing of product materials with infill structure, which provides advantages such as reduced production time, product weight and even the final price. In this paper, the tensile mechanical properties, tensile strength and elastic modulus, of PLA, Tough PLA and PC FDM 3D printed materials with the infill structure were analysed and compared. Also, the influence of infill pattern on tensile properties was analysed. Material testing were performed according to ISO 527-2 standard. All results are statistically analysed and results showed that infill pattern have influence on tensile mechanical properties for all three materials.

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Evaluation of the Compatibility of Organosolv Lignin-Graphene Nanoplatelets with Photo-Curable Polyurethane in Stereolithography 3D Printing

Polymers ◽

10.3390/polym11101544 ◽

2019 ◽

Vol 11 (10) ◽

pp. 1544 ◽

Cited By ~ 8

Author(s):

Fathirrahman Ibrahim ◽

Denesh Mohan ◽

Mohd Shaiful Sajab ◽

Saiful Bahari Bakarudin ◽

Hatika Kaco

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

3D Printing ◽

Oil Palm ◽

Structural Changes ◽

Graphene Nanoplatelets ◽

Empty Fruit Bunch ◽

Organosolv Lignin ◽

3D Printed

In this study, lignin has been extracted from oil palm empty fruit bunch (EFB) fibers via an organosolv process. The organosolv lignin obtained was defined by the presence of hydroxyl-containing molecules, such as guaiacyl and syringyl, and by the presence of phenolic molecules in lignin. Subsequently, the extracted organosolv lignin and graphene nanoplatelets (GNP) were utilized as filler and reinforcement in photo-curable polyurethane (PU), which is used in stereolithography 3D printing. The compatibility as well as the characteristic and structural changes of the composite were identified through the mechanical properties of the 3D-printed composites. Furthermore, the tensile strength of the composited lignin and graphene shows significant improvement as high as 27%. The hardness of the photo-curable PU composites measured by nanoindentation exhibited an enormous improvement for 0.6% of lignin-graphene at 92.49 MPa with 238% increment when compared with unmodified PU.

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Accelerated Aging Effect on Mechanical Properties of Common 3D-Printing Polymers

Polymers ◽

10.3390/polym13234132 ◽

2021 ◽

Vol 13 (23) ◽

pp. 4132

Author(s):

Catalin Gheorghe Amza ◽

Aurelian Zapciu ◽

Florin Baciu ◽

Mihai Ion Vasile ◽

Adrian Ionut Nicoara

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Structural Changes ◽

Prolonged Exposure ◽

Accelerated Aging ◽

Aging Treatment ◽

Aging Effect ◽

Control Group ◽

Outdoor Environments ◽

3D Printed

In outdoor environments, the action of the Sun through its ultraviolet radiation has a degrading effect on most materials, with polymers being among those affected. In the past few years, 3D printing has seen an increased usage in fabricating parts for functional applications, including parts destined for outdoor use. This paper analyzes the effect of accelerated aging through prolonged exposure to UV-B on the mechanical properties of parts 3D printed from the commonly used polymers polylactic acid (PLA) and polyethylene terephthalate–glycol (PETG). Samples 3D printed from these materials went through a dry 24 h UV-B exposure aging treatment and were then tested against a control group for changes in mechanical properties. Both the tensile and compressive strengths were determined, as well as changes in material creep characteristics. After irradiation, PLA and PETG parts saw significant decreases in both tensile strength (PLA: −5.3%; PETG: −36%) and compression strength (PLA: −6.3%; PETG: −38.3%). Part stiffness did not change significantly following the UV-B exposure and creep behavior was closely connected to the decrease in mechanical properties. A scanning electron microscopy (SEM) fractographic analysis was carried out to better understand the failure mechanism and material structural changes in tensile loaded, accelerated aged parts.

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Comparing Properties of Variable Pore-Sized 3D-Printed PLA Membrane with Conventional PLA Membrane for Guided Bone/Tissue Regeneration

Materials ◽

10.3390/ma12101718 ◽

2019 ◽

Vol 12 (10) ◽

pp. 1718 ◽

Cited By ~ 7

Author(s):

Hao Yang Zhang ◽

Heng Bo Jiang ◽

Jeong-Hyun Ryu ◽

Hyojin Kang ◽

Kwang-Mahn Kim ◽

...

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Bone Tissue Regeneration ◽

Control Group ◽

Micro Computed Tomography ◽

Barrier Membranes ◽

Pore Sizes ◽

Small Pore ◽

Superior Mechanical Properties ◽

3D Printed

The aim of this study was to fabricate bioresorbable polylactide (PLA) membranes by 3D printing and compare their properties to those of the membranes fabricated by the conventional method and compare the effect of different pore sizes on the properties of the 3D-printed membranes. PLA membranes with three different pore sizes (large pore-479 μm, small pore-273 μm, and no pore) were 3D printed, and membranes fabricated using the conventional solvent casting method were used as the control group. Scanning electron microscopy (SEM) and micro-computed tomography (µ-CT) were taken to observe the morphology and obtain the porosity of the four groups. A tensile test was performed to compare the tensile strength, elastic modulus, and elongation at break of the membranes. Preosteoblast cells were cultured on the membranes for 1, 3 and 7 days, followed by a WST assay and SEM, to examine the cell proliferation on different groups. As a result, the 3D-printed membranes showed superior mechanical properties to those of the solvent cast membranes, and the 3D-printed membranes exhibited different advantageous mechanical properties depending on the different pore sizes. The various fabrication methods and pore sizes did not have significantly different effects on cell growth. It is proven that 3D printing is a promising method for the fabrication of customized barrier membranes used in GBR/GTR.

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Mechanical Performance Analysis of ULTEM 9085 in a Heated, Irradiated Environment

Volume 9: Mechanics of Solids, Structures, and Fluids ◽

10.1115/imece2018-88181 ◽

2018 ◽

Author(s):

Matthew B. Ng ◽

Sean N. Brennan

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Mechanical Performance ◽

Cost Effective ◽

Radiation Environment ◽

Inspection System ◽

Control Group ◽

Inspection Systems ◽

3D Printed ◽

Cost Efficient

This paper investigates the thermal and radiation performance of 3D-printed ULTEM materials following ASTM standard D638. ULTEM is a thermoplastic in the polyetherimide (PEI) family that is regularly used as a high-grade material for 3D printing. This material has similar properties to polyether ether ketone (PEEK), which is another thermoplastic that has strong mechanical properties at elevated temperature conditions. While PEEK has stronger mechanical properties, ULTEM is significantly more cost efficient to acquire and process via 3D printing. Also, most 3D printers are unable to utilize PEEK because of the significantly higher temperature requirements this material imposes on a 3D printer. This work is motivated by the need to rapidly deploy robotic inspection systems within a nuclear canister environment, which exposes the material to temperatures up to 170°C (340°F), and radiation levels of 270 Gy/hr (27 krad/hr), which are significantly beyond that of conventional 3D-printed parts. The design analysis was performed via an experiment consisting of three treatment groups of dogbone ULTEM test pieces. After tensile testing all of the pieces, the material properties were compared to those of the control group. These results allow manufacturers to select a more cost-effective material to build parts to operate in such a harsh high-temperature, high-radiation environment, which could include applications in both space systems and nuclear inspection robotics. Specifically, the results were used to guide the development of a robust robotic inspection system for the Nuclear Energy University Program (NEUP) by replacing complex parts with easily-fabricated 3D-printed ULTEM pieces.

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The Influence of Layer Thickness on Mechanical Properties of the 3D Printed ABS Polymer by Fused Deposition Modeling

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.706.63 ◽

2016 ◽

Vol 706 ◽

pp. 63-67 ◽

Cited By ~ 10

Author(s):

Pritish Shubham ◽

Arnab Sikidar ◽

Teg Chand

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Impact Strength ◽

Injection Molding ◽

Layer Thickness ◽

Fused Deposition Modeling ◽

Molding Method ◽

Fused Deposition ◽

Deposition Modeling ◽

3D Printed

3D Printed ABS polymer samples were investigated for understanding the effect of layer thickness on the various mechanical properties of the component. Standard samples with varying layer thickness were prepared by 3D printing machine which works on the principle of Fused Deposition modeling (FDM) method and compared with sample prepared by standard injection molding method. Results show that tensile strength (36 MPa), impact strength (103.6 J/m) and hardness (R107) were highest for the samples made by injection molding method. Furthermore, among 3D printed samples, properties were better with smaller layer thickness. With increase in layer thickness, there was negative effect on mechanical properties as tensile strength, impact strength and hardness decreased. Exception with hardness of 3D printed ABS samples was found; for largest layer thickness hardness further increased instead of decreasing.

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Characteristic Investigations on Loofah, Jute and Glass Fiber Reinforced Sandwich Polymeric Composites

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.813-814.14 ◽

2015 ◽

Vol 813-814 ◽

pp. 14-18 ◽

Cited By ~ 4

Author(s):

R. Vinayagamoorthy ◽

S. Sivanarasimha ◽

K.R. Vinay Kumar ◽

Vijay Padmanabhan

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Tensile Strength ◽

Compressive Strength ◽

Glass Fibers ◽

Resin Content ◽

Distilled Water ◽

Biodegradable Composites ◽

Glass Fiber Reinforced ◽

Reinforcing Fibers

In this study, new biodegradable composites were developed with loofah, jute and commercial E-glass as reinforcing fibers and poly ester as the resin. Loofah fibers are preheated with distilled water and alkali followed by heat treatment in order to enhance its surface properties. Four composite materials are prepared by varying the proportions of natural and glass fibers in each and maintaining the resin content as a constant. The specimens were subjected to testing of mechanical properties namely tensile strength, compressive strength, flexural strength and impact strength. The results revealed that the mechanical properties like tensile, flexural and impact strengths were high when proportions of all fibers are equal. Also, compressive strength was higher with sample containing only loofah fibers.

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Combining Materials Obtained by 3D-Printing and Electrospinning from Commercial Polylactide Filament to Produce Biocompatible Composites

Polymers ◽

10.3390/polym13213806 ◽

2021 ◽

Vol 13 (21) ◽

pp. 3806

Author(s):

Pablo Romero-Araya ◽

Victor Pino ◽

Ariel Nenen ◽

Verena Cárdenas ◽

Francisca Pavicic ◽

...

Keyword(s):

Mechanical Properties ◽

Tissue Engineering ◽

3D Printing ◽

Three Dimensional ◽

Fibrillar Structure ◽

3D Print ◽

3T3 Fibroblasts ◽

Custom Made ◽

3D Printers ◽

3D Printed

The design of scaffolds to reach similar three-dimensional structures mimicking the natural and fibrous environment of some cells is a challenge for tissue engineering, and 3D-printing and electrospinning highlights from other techniques in the production of scaffolds. The former is a well-known additive manufacturing technique devoted to the production of custom-made structures with mechanical properties similar to tissues and bones found in the human body, but lacks the resolution to produce small and interconnected structures. The latter is a well-studied technique to produce materials possessing a fibrillar structure, having the advantage of producing materials with tuned composition compared with a 3D-print. Taking the advantage that commercial 3D-printers work with polylactide (PLA) based filaments, a biocompatible and biodegradable polymer, in this work we produce PLA-based composites by blending materials obtained by 3D-printing and electrospinning. Porous PLA fibers have been obtained by the electrospinning of recovered PLA from 3D-printer filaments, tuning the mechanical properties by blending PLA with small amounts of polyethylene glycol and hydroxyapatite. A composite has been obtained by blending two layers of 3D-printed pieces with a central mat of PLA fibers. The composite presented a reduced storage modulus as compared with a single 3D-print piece and possessing similar mechanical properties to bone tissues. Furthermore, the biocompatibility of the composites is assessed by a simulated body fluid assay and by culturing composites with 3T3 fibroblasts. We observed that all these composites induce the growing and attaching of fibroblast over the surface of a 3D-printed layer and in the fibrous layer, showing the potential of commercial 3D-printers and filaments to produce scaffolds to be used in bone tissue engineering.

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Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.14.2.2020.15.0527 ◽

2020 ◽

Vol 14 (2) ◽

pp. 6734-6742

Author(s):

A. Syamsir ◽

S. M. Mubin ◽

N. M. Nor ◽

V. Anggraini ◽

S. Nagappan ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Compressive Strength ◽

Reinforced Concrete ◽

Impact Resistance ◽

Fiber Reinforced Concrete ◽

Steel Fibers ◽

Fiber Reinforced ◽

Indirect Tensile ◽

The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study. The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.

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