Effect of 3D printing direction and water storage on nano-mechanical properties of 3D printed and auto-polymerized polymer with special emphasis on printing layer interface

Purpose This papers aims to study the influence of water absorption on the mechanical properties of poly lactic acid (PLA) and PLA/Wood composites. Virgin PLA and PLA/Wood double-bone-shaped specimens were prepared by two methods: injection moulding and 3D printing. The results were compared to each other and showed the influence of the production method on the properties of the produced parts. Design/methodology/approach Morphology studies were done by scanning electron microscopy (SEM) from fracture surfaces of tensile and notched impact specimens of all samples. Tensile properties were analysed by the production and testing of dog-bone-shaped samples. Heat deflection temperature (HDT) was tested, as also was the crystallinity of the tested samples by differential scanning calorimetry. Findings The values for notched impact strength were higher upon water uptake in the case of injection-moulded specimens, which was not the case with 3D-printed specimens. Tensile properties of the specimens produced by both methods were reduced after water absorption tests. Values of the HDT were also lower after water absorption tests studied for both processing methods. Originality/value Morphology studies were done by SEM from fracture surfaces of tensile as well as notched impact specimens of injection-moulded and 3D-printed samples. The effect of water storage on various samples was tested. The two different production technologies were compared to each other owing to their influence of water storage. This study also dealt with NFC compounds and produced NFC composites and the influence of water storage on these samples.

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Poly(ether ether ketone)s processed through extrusion-machining and 3D printing: A comparative study on mechanical, thermal and fracture properties at ambient and cryogenic environments

Journal of Elastomers & Plastics ◽

10.1177/0095244320961830 ◽

2020 ◽

pp. 009524432096183

Author(s):

Leena Karthikeyan ◽

Suraj Sudhi ◽

Tushar Shriram Bhatt ◽

Mani Ganesan ◽

Panthaplackal Bhaskaran Soumyamol ◽

...

Keyword(s):

Mechanical Properties ◽

Thermal Expansion ◽

3D Printing ◽

Fracture Morphology ◽

Morphological Studies ◽

Ether Ether Ketone ◽

Poly Ether Ether Ketone ◽

3D Printed ◽

Ether Ketone ◽

Printing Direction

Poly Ether Ether Ketone (PEEK) is a very promising engineering thermoplastic material having capability to perform over wide service temperatures from cryogenic to around 300°C. Processing of PEEK is a challenging task, owing to its physical, thermo physical properties and chemical nature. The present paper envisages processing of PEEK by two different techniques viz, 3D printing and extrusion and assessment of properties of respective specimens at 30°C and −196°C. Thermal and mechanical properties and fracture morphological features of PEEK specimen, processed using these techniques are compared. Samples processed by extrusion possessed higher mechanical properties both at 30°C and −196°C. The 3D printed samples, though exhibited inferior strength and modulus, showed significantly higher elongation (150–250%) at 30°C. All samples showed ductile fracture behavior at 30°C. At −196°C, the fracture morphology got transformed in to a pattern typical of brittle materials, as expected. Extruded specimens showed lower thermal expansion coefficient compared to the 3D printed specimens. Thermal expansion characteristics were different in the X, Y and Z directions for 3D printed specimens due to the anisotropy resulting from printing direction which is corroborated by the morphological studies. The results of this investigation enable designing and fabrication of PEEK based structural components of desired geometries for various applications.

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Mechanical Properties of 3D-Printed Wood-Plastic Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.777.499 ◽

2018 ◽

Vol 777 ◽

pp. 499-507 ◽

Cited By ~ 4

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.

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Effect of temperature on the mechanical properties of 3D-printed PLA tensile specimens

Rapid Prototyping Journal ◽

10.1108/rpj-04-2017-0055 ◽

2018 ◽

Vol 24 (8) ◽

pp. 1337-1346 ◽

Cited By ~ 12

Author(s):

Marzio Grasso ◽

Lyes Azzouz ◽

Paula Ruiz-Hincapie ◽

Mauro Zarrelli ◽

Guogang Ren

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Mechanical Test ◽

Optical Microscope ◽

Middle Part ◽

Gauge Length ◽

Effect Of Temperature ◽

Content Type ◽

Relevant Effect ◽

3D Printed

Purpose Recent advancements of 3D printing technology have brought forward the interest for this technique in many engineering fields. This study aims to focus on mechanical properties of the polylactic acid (PLA) feeding material under different thermal conditions for a typical fusion deposition of 3D printer system. Design/methodology/approach Specimens were tested under static loading within the range 20ºC to 60ºC considering different infill orientations. The combined effect of temperature and filament orientation is investigated in terms of constitutive material parameters and final failure mechanisms. The difference between feeding system before and post-3D printing was also assessed by mechanical test on feeding filament to verify the thermal profile during the deposition phase. Findings The results in terms of Young’s modulus, ultimate tensile strength (UTS), strain at failure (εf) and stress at failure (σf) are presented and discussed to study the influence of process settings over the final deposited material. Fracture surfaces have been investigated using an optical microscope to link the phenomenological interpretation of the failure with the micro-mechanical behaviour. Experimental results show a strong correlation between stiffness and strength with the infill orientation and the temperature values. Moreover, a relevant effect is related to deformed geometry of the filament approaching glass transition region of the polymer according to the deposition orientation. Research limitations/implications The developed method can be applied to optimise the stiffness and strength of any 3D-printed composite according to the infill orientation. Practical implications To avoid the failure of specimens outside the gauge length, a previously proposed modification to the geometry was adopted. The geometry has a parabolic profile with a curvature of 1,000 mm tangent to the middle part of the specimen. Originality/value Several authors have reported the stiffness and strength of 3D-printed parts under static and ambient temperature for different build parameters. However, there is a lack of literature on the combination of the latter with the temperature effects on the mechanical properties which this paper covers.

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A physical investigation of dimensional and mechanical characteristics of 3D printed nut and bolt for industrial applications

Rapid Prototyping Journal ◽

10.1108/rpj-09-2021-0250 ◽

2022 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Ramesh Chand ◽

Vishal S. Sharma ◽

Rajeev Trehan ◽

Munish Kumar Gupta

Keyword(s):

Mechanical Properties ◽

Shear Strength ◽

3D Printing ◽

Surface Properties ◽

3D Printer ◽

Content Type ◽

Safety Issues ◽

Machine Failure ◽

Sharp Edges ◽

3D Printed

Purpose A nut bolt joint is a primary device that connects mechanical components. The vibrations cause bolted joints to self-loosen. Created by motors and engines, leading to machine failure, and there may be severe safety issues. All the safety issues and self-loosen are directly and indirectly the functions of the accuracy and precision of the fabricated nut and bolt. Recent advancements in three-dimensional (3D) printing technologies now allow for the production of intricate components. These may be used technologies such as 3D printed bolts to create fasteners. This paper aims to investigate dimensional precision, surface properties, mechanical properties and scanning electron microscope (SEM) of the component fabricated using a multi-jet 3D printer. Design/methodology/approach Multi-jet-based 3D printed nut-bolt is evaluated in this paper. More specifically, liquid polymer-based nut-bolt is fabricated in sections 1, 2 and 3 of the base plate. Five nuts and bolts are fabricated in these three sections. Findings Dimensional inquiry (bolt dimension, general dimensions’ density and surface roughness) and mechanical testing (shear strength of nut and bolt) were carried out throughout the study. According to the ISO 2768 requirements for the General Tolerances Grade, the nut and bolt’s dimensional examination (variation in bolt dimension, general dimensions) is within the tolerance grades. As a result, the multi-jet 3D printing (MJP)-based 3D printer described above may be used for commercial production. In terms of mechanical qualities, when the component placement moves from Sections 1 to 3, the density of the manufactured part decreases by 0.292% (percent) and the shear strength of the nut and bolt decreases by 30%. According to the SEM examination, the density of the River markings, sharp edges, holes and sharp edges increased from Sections 1 to 3, which supports the findings mentioned above. Originality/value Hence, this work enlightens the aspects causing time lag during the 3D printing in MJP. It causes variation in the dimensional deviation, surface properties and mechanical properties of the fabricated part, which needs to be explored.

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Effects of post-curing conditions on mechanical properties of 3D printed clear dental aligners

Rapid Prototyping Journal ◽

10.1108/rpj-04-2019-0118 ◽

2020 ◽

Vol 26 (8) ◽

pp. 1337-1344 ◽

Cited By ~ 1

Author(s):

Prashant Jindal ◽

Mamta Juneja ◽

Divya Bajaj ◽

Francesco Luke Siena ◽

Philip Breedon

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Mechanical Strength ◽

Financial Burden ◽

Experimental Studies ◽

Cost Savings ◽

Time Duration ◽

Content Type ◽

Curing Conditions ◽

3D Printed

Purpose 3D printing techniques have been widely used for manufacturing complex parts for various dental applications. For achieving suitable mechanical strength, post-cure processing is necessary, where the relative time duration and temperature specification also needs to be defined. The purpose of this study/paper is to assess the effects of post curing conditions and mechanical properties of 3D printed clear dental aligners Design/methodology/approach Dental long-term clear resin material has been used for 3D printing of dental aligners using a Formlabs 3D printer for direct usage on patients. Post-curing conditions have been varied, all of which have been subjected to mechanical compression loading of 1,000 N to evaluate the curing effects on the mechanical strength of the aligners. Findings The experimental studies provide significant insight into both temperatures and time durations that could provide sufficient compressive mechanical strength to the 3D printed clear dental aligners. It was observed that uncured aligners deformed plastically with large deformations under the loading conditions, whereas aligners cured between 400°C–800°C for 15–20 min deformed elastically before fragmenting into pieces after safely sustaining higher compressive loads between 495 N and 666 N. The compressive modulus ratio for cured aligners ranged between 4.46 and 5.90 as compared to uncured aligners. For shorter cure time durations and lower temperature conditions, an appropriate elevated compressive strength was also achieved. Originality/value Based on initial assessments by dental surgeons, suitable customised clear aligners can be designed, printed and cured to the desired levels based on patient’s requirements. This could result in time, energy and unit production cost savings, which ultimately would help to alleviate the financial burden placed on both the health service and their patients.

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On effect of chemical-assisted mechanical blending of barium titanate and graphene in PVDF for 3D printing applications

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705720945377 ◽

2020 ◽

pp. 089270572094537

Author(s):

Ravinder Sharma ◽

Rupinder Singh ◽

Ajay Batish

Keyword(s):

Mechanical Properties ◽

Barium Titanate ◽

3D Printing ◽

Comparative Study ◽

Process Parameters ◽

Processing Temperature ◽

Melt Mixing ◽

Twin Screw ◽

3D Printed ◽

The Comparative Study

The polyvinylidene difluoride + barium titanate (BaTiO3) +graphene composite (PBGC) is one of the widely explored thermoplastic matrix due to its 4D capabilities. The number of studies has been reported on the process parameters of twin-screw extruder (TSE) setup (as mechanical blending technique) for the development of PBGC in 3D printing applications. But, hitherto, little has been reported on chemical-assisted mechanical blending (CAMB) as solution mixing and melt mixing technique combination for preparation of PBGC. In this work, for preparation of PBGC feedstock filaments, CAMB has been used. Also, the effect of process parameters of TSE on the mechanical, dimensional, morphological, and thermal properties of prepared filament of PBGC have been explored followed by 3D printing. Further, a comparative study has been reported for the properties of prepared filaments with mechanically blended composites. Similarly, the mechanical properties of 3D printed parts of chemically and mechanically blended composites have been compared. The results of tensile testing for CAMB of PBGC show that the filament prepared with 15% BaTiO3 is having maximum peak strength 43.00 MPa and break strength 38.73 MPa. The optical microphotographs of the extruded filaments revealed that the samples prepared at 180°C extruder temperature and 60 r/min screw speed have minimum porosity, as compared to filaments prepared at high extruder temperature. Further, the results of the comparative study revealed that the filaments of CAMB composites show better mechanical properties as compared to the filaments of mechanically mixed composites. However, the dimensional properties were almost similar in both cases. It was also found that the CAMB composites have better properties at low processing temperature, whereas mechanically blended composites show better results at a higher temperature. While comparing 3D printed parts, tensile strength of specimens fabricated from CAMB was more than the mechanically blended PBGC.

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3D printing of biofiber-reinforced composites and their mechanical properties: a review

Rapid Prototyping Journal ◽

10.1108/rpj-08-2019-0214 ◽

2020 ◽

Vol 26 (6) ◽

pp. 1113-1129

Author(s):

Lai Jiang ◽

Xiaobo Peng ◽

Daniel Walczyk

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Reinforced Composites ◽

Research Directions ◽

Content Type ◽

Reinforced Composite ◽

3D Printed ◽

Materials Used ◽

Printing Processes ◽

Pure Resin

Purpose This paper aims to summarize the up-to-date research performed on combinations of various biofibers and resin systems used in different three-dimensional (3D) printing technologies, including powder-based, material extrusion, solid-sheet and liquid-based systems. Detailed information about each process, including materials used and process design, are described, with the resultant products’ mechanical properties compared with those of 3D-printed parts produced from pure resin or different material combinations. In most processes introduced in this paper, biofibers are beneficial in improving the mechanical properties of 3D-printed parts and the biodegradability of the parts made using these green materials is also greatly improved. However, research on 3D printing of biofiber-reinforced composites is still far from complete, and there are still many further studies and research areas that could be explored in the future. Design/methodology/approach The paper starts with an overview of the current scenario of the composite manufacturing industry and then the problems of advanced composite materials are pointed out, followed by an introduction of biocomposites. The main body of the paper covers literature reviews of recently emerged 3D printing technologies that were applied to biofiber-reinforced composite materials. This part is classified into subsections based on the form of the starting materials used in the 3D printing process. A comprehensive conclusion is drawn at the end of the paper summarizing the findings by the authors. Findings Most of the biofiber-reinforced 3D-printed products exhibited improved mechanical properties than products printed using pure resin, indicating that biofibers are good replacements for synthetic ones. However, synthetic fibers are far from being completely replaced by biofibers due to several of their disadvantages including higher moisture absorbance, lower thermal stability and mechanical properties. Many studies are being performed to solve these problems, yet there are still some 3D printing technologies in which research concerning biofiber-reinforced composite parts is quite limited. This paper unveils potential research directions that would further develop 3D printing in a sustainable manner. Originality/value This paper is a summary of attempts to use biofibers as reinforcements together with different resin systems as the starting material for 3D printing processes, and most of the currently available 3D printing techniques are included herein. All of these attempts are solutions to some principal problems with current 3D printing processes such as the limit in the variety of materials and the poor mechanical performance of 3D printed parts. Various types of biofibers are involved in these studies. This paper unveils potential research directions that would further widen the use of biofibers in 3D printing in a sustainable manner.

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DLP 3D Printing Meets Lignocellulosic Biopolymers: Carboxymethyl Cellulose Inks for 3D Biocompatible Hydrogels

Polymers ◽

10.3390/polym12081655 ◽

2020 ◽

Vol 12 (8) ◽

pp. 1655 ◽

Cited By ~ 4

Author(s):

Giuseppe Melilli ◽

Irene Carmagnola ◽

Chiara Tonda-Turo ◽

Fabrizio Pirri ◽

Gianluca Ciardelli ◽

...

Keyword(s):

Mechanical Properties ◽

Additive Manufacturing ◽

3D Printing ◽

Carboxymethyl Cellulose ◽

Biomedical Applications ◽

Digital Light Processing ◽

Chemically Modified ◽

Significant Step ◽

3D Printed ◽

Biomedical Field

The development of new bio-based inks is a stringent request for the expansion of additive manufacturing towards the development of 3D-printed biocompatible hydrogels. Herein, methacrylated carboxymethyl cellulose (M-CMC) is investigated as a bio-based photocurable ink for digital light processing (DLP) 3D printing. CMC is chemically modified using methacrylic anhydride. Successful methacrylation is confirmed by 1H NMR and FTIR spectroscopy. Aqueous formulations based on M-CMC/lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) photoinitiator and M-CMC/Dulbecco’s Modified Eagle Medium (DMEM)/LAP show high photoreactivity upon UV irradiation as confirmed by photorheology and FTIR. The same formulations can be easily 3D-printed through a DLP apparatus to produce 3D shaped hydrogels with excellent swelling ability and mechanical properties. Envisaging the application of the hydrogels in the biomedical field, cytotoxicity is also evaluated. The light-induced printing of cellulose-based hydrogels represents a significant step forward in the production of new DLP inks suitable for biomedical applications.

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Mechanical Properties of Diamond Schwarzites: From Atomistic Models to 3D-Printed Structures

MRS Advances ◽

10.1557/adv.2020.175 ◽

2020 ◽

Vol 5 (33-34) ◽

pp. 1775-1781 ◽

Cited By ~ 1

Author(s):

Levi C. Felix ◽

Vladimir Gaál ◽

Cristiano F. Woellner ◽

Varlei Rodrigues ◽

Douglas S. Galvao

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Uniaxial Compression ◽

Chemical Vapour ◽

Md Simulations ◽

Atomic Model ◽

Fused Deposition Modelling ◽

Fused Deposition ◽

Structural Applications ◽

3D Printed

ABSTRACTTriply Periodic Minimal Surfaces (TPMS) possess locally minimized surface area under the constraint of periodic boundary conditions. Different families of surfaces were obtained with different topologies satisfying such conditions. Examples of such families include Primitive (P), Gyroid (G) and Diamond (D) surfaces. From a purely mathematical subject, TPMS have been recently found in materials science as optimal geometries for structural applications. Proposed by Mackay and Terrones in 1991, schwarzites are 3D crystalline porous carbon nanocrystals exhibiting a TPMS-like surface topology. Although their complex topology poses serious limitations on their synthesis with conventional nanoscale fabrication methods, such as Chemical Vapour Deposition (CVD), schwarzites can be fabricated by Additive Manufacturing (AM) techniques, such as 3D Printing. In this work, we used an optimized atomic model of a schwarzite structure from the D family (D8bal) to generate a surface mesh that was subsequently used for 3D-printing through Fused Deposition Modelling (FDM). This D schwarzite was 3D-printed with thermoplastic PolyLactic Acid (PLA) polymer filaments. Mechanical properties under uniaxial compression were investigated for both the atomic model and the 3D-printed one. Fully atomistic Molecular Dynamics (MD) simulations were also carried out to investigate the uniaxial compression behavior of the D8bal atomic model. Mechanical testings were performed on the 3D-printed schwarzite where the deformation mechanisms were found to be similar to those observed in MD simulations. These results are suggestive of a scale-independent mechanical behavior that is dominated by structural topology.

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