scholarly journals Comparison between Tests and Simulations Regarding Bending Resistance of 3D Printed PLA Structures

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4371
Author(s):  
Dorin-Ioan Catana ◽  
Mihai-Alin Pop ◽  
Denisa-Iulia Brus
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Process Parameters ◽  
Bending Stress ◽  
Test Results ◽  
Printing Process ◽  
Simulation Process ◽  
Bending Resistance ◽  
3D Printed

Additive manufacturing is one of the technologies that is beginning to be used in new fields of parts production, but it is also a technology that is constantly evolving, due to the advances made by researchers and printing equipment. The paper presents how, by using the simulation process, the geometry of the 3D printed structures from PLA and PLA-Glass was optimized at the bending stress. The optimization aimed to reduce the consumption of filament (material) simultaneously with an increase in the bending resistance. In addition, this paper demonstrates that the simulation process can only be applied with good results to 3D printed structures when their mechanical properties are known. The inconsistency of printing process parameters makes the 3D printed structures not homogeneous and, consequently, the occurrence of errors between the test results and those of simulations become natural and acceptable. The mechanical properties depend on the values of the printing process parameters and the printing equipment because, in the case of 3D printing, it is necessary for each combination of parameters to determine their mechanical properties through specific tests.

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

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.

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

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1655 ◽  
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.

scholarly journals Property Analysis of Photo-Polymerization-Type 3D-Printed Structures Based on Multi-Composite Materials

2021 ◽  
Vol 11 (18) ◽  
pp. 8545
Author(s):  
So-Ree Hwang ◽  
Min-Soo Park
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Composite Materials ◽  
3D Printing ◽  
Bending Test ◽  
3D Printer ◽  
Complex Structures ◽  
Photo Polymerization ◽  
Anisotropic Structures ◽  
3D Printed

Additive manufacturing, commonly called 3D printing, has been studied extensively because it can be used to fabricate complex structures; however, polymer-based 3D printing has limitations in terms of implementing certain functionalities, so it is limited in the production of conceptual prototypes. As such, polymer-based composites and multi-material 3D printing are being studied as alternatives. In this study, a DLP 3D printer capable of printing multiple composite materials was fabricated using a movable separator and structures with various properties were fabricated by selectively printing two composite materials. After the specimen was fabricated based on the ASTM, the basic mechanical properties of the structure were compared through a 3-point bending test and a ball rebound test. Through this, it was shown that structures with various mechanical properties can be fabricated using the proposed movable-separator-based DLP process. In addition, it was shown that this process can be used to fabricate anisotropic structures, whose properties vary depending on the direction of the force applied to the structure. By fabricating multi-joint grippers with varying levels of flexibility, it was shown that the proposed process can be applied in the fabrication of soft robots as well.

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.

Mechanical Properties of 3D Printed Biomimicked Composites

2018 ◽  
Author(s):  
Seyed M. Allameh ◽  
Roger Miller ◽  
Hadi Allameh
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Soft Materials ◽  
Structural Composites ◽  
Home Building ◽  
Complex Shapes ◽  
3D Printed ◽  
Bend Tests ◽  
Point Bend

Additive manufacturing technology has significantly matured over the last two decades. Recent progress in 3D printing has made it an attractive choice for fabricating complex shapes out of select materials possessing desirable properties at small and large scales. The application of biomimetics to the fabrication of structural composites has been shown to enhance their toughness and dynamic shear resistance. Building homes from bioinspired composites is possible if the process is automated. This can be achieved through additive manufacturing where layers of hard and soft materials can be deposited by 3D printing. This study examines mechanical properties of reinforced concrete fabricated by 3D printing. Preliminary results of 4-point bend tests are presented and the implications of 3D-printed home building on current conventional construction practices are discussed.

Metallographic and Fractographic Evaluation of 3D-Printed Titanium Samples to Eliminate Unsatisfactory Mechanical Properties

2017 ◽  
Vol 270 ◽  
pp. 212-217
Author(s):  
Michaela Fousová ◽  
Tereza Stejskalova ◽  
Dalibor Vojtěch
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
3D Printing ◽  
Process Parameters ◽  
Patient Specific ◽  
Medical Implants ◽  
Laser Melting ◽  
Patient Specific Implants ◽  
3D Printed ◽  
Set Up

Czech company ProSpon spol. s r.o. has introduced 3D printing technology in its production in 2015. This company operates in the field of development, manufacture and distribution of medical implants and instruments for orthopedics, traumatology and surgery. Therefore, the current intention is to employ Selective Laser Melting (SLM) technology for production of complex and patient-specific implants from titanium alloy Ti-6Al-4V. Nevertheless, first series of produced test specimens suffered from very low plasticity insufficient for the intended application. The reduction in elongation was almost 7fold compared to conventionally used wrought standard. From that reason, specimens were subjected to fractographic evaluation of fracture surfaces, but also metallographic evaluation. The main cause of the identified problem turned out to be porosity originating from inappropriate set-up of the machine. After the adjustment of process parameters new series of specimens were prepared in which the porosity was already significantly lower. Consequently, mechanical properties reached higher and better values.

scholarly journals Effect of Printing Process Parameters on the Shape Transformation Capability of 3D Printed Structures

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 117
Author(s):  
Matej Pivar ◽  
Diana Gregor-Svetec ◽  
Deja Muck
Keyword(s):  
3D Printing ◽  
Process Parameters ◽  
Active Material ◽  
Hot Water ◽  
Shape Transformation ◽  
Printing Process ◽  
Speed Flow ◽  
Layer Structures ◽  
3D Printed ◽  
Active Segment

The aim of our research was to investigate and optimise the main 3D printing process parameters that directly or indirectly affect the shape transformation capability and to determine the optimal transformation conditions to achieve predicted extent, and accurate and reproducible transformations of 3D printed, shape-changing two-material structures based on PLA and TPU. The shape-changing structures were printed using the FDM technology. The influence of each printing parameter that affects the final printability of shape-changing structures is presented and studied. After optimising the 3D printing process parameters, the extent, accuracy and reproducibility of the shape transformation performance for four-layer structures were analysed. The shape transformation was performed in hot water at different activation temperatures. Through a careful selection of 3D printing process parameters and transformation conditions, the predicted extent, accuracy and good reproducibility of shape transformation for 3D printed structures were achieved. The accurate deposition of filaments in the layers was achieved by adjusting the printing speed, flow rate and cooling conditions of extruded filaments. The shape transformation capability of 3D printed structures with a defined shape and defined active segment dimensions was influenced by the relaxation of compressive and tensile residual stresses in deposited filaments in the printed layers of the active material and different activation temperatures of the transformation.

scholarly journals Application of a Cold Spray Based 3D Printing Process in the Production of EDM Electrodes

2020 ◽  
Vol 14 (1) ◽  
pp. 27-31
Author(s):  
Štefanija Klarić ◽  
Zlatko Botak ◽  
Damien J. Hill ◽  
Matthew Harbidge ◽  
Rebecca Murray
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Cold Spray ◽  
Electrical Discharge Machining ◽  
Printing Process ◽  
Spray Process ◽  
Layer Deposition ◽  
Edm Electrodes ◽  
3D Printed ◽  
Near Net Shape

Cold spray process principles allow the production of near-net-shape metal parts with a fast layer deposition by using 3D printing techniques via supersonic 3D deposition (SP3D). This innovative additive manufacturing process allows an easy and quick production of copper and aluminium parts with future possibilities to expand materials and alloys. The speed and materials enable the application of this cold spray based 3D printing process for the production of tools. In this paper, Electrical Discharge Machining (EDM) electrodes were fabricated by using SP3D to investigate its application in tool production. Requirements for the materials of electrodes and some existing solutions for the production of EDM electrodes with additive manufacturing methods are described first. The fabrication and experimental results are then presented for 3D printed copper EDM electrodes that were tested by using St 37-2 (DIN 17100) steel as the workpiece.

Anisotropic Material Behaviors of 3D Printed Carbon-Fiber Polymer Composites With Open-Source Printers

2021 ◽  
Author(s):  
Jordan Garcia ◽  
Robert Harper ◽  
Y. Charles Lu
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Carbon Fiber ◽  
3D Printing ◽  
Open Source ◽  
Polymer Composites ◽  
Mechanical Responses ◽  
Manufacturing Technique ◽  
3D Printed ◽  
Traditional Manufacturing

Abstract Composite products are often created using traditional manufacturing methods such as compression or injection molding. Recently, additive manufacturing (3D printing) techniques have been used for fabricating composites. 3D printing is the process of producing three-dimensional parts through the successive combination of various layers of material. This layering effect in combination with exposure to ambient (or reduced) temperature and pressure cause the finished products to have inconsistent microstructures. The inconsistent microstructures along with the oriented reinforcing fibers create anisotropic parts with difficulty to predict mechanical properties. In this paper, the mechanical properties of fiber reinforced polymer composites produced by additive manufacturing technique (3D printing) and by traditional manufacturing technique (compression molding) were investigated. Three open-source 3D printers, i.e. FlashForge Dreamer, Tevo Tornado, and Prusa i3 Mk3, were used to fabricate bending samples from carbon-fiber reinforced ABS (acrylonitrile butadiene styrene). Results showed that there exist significant discrepancies and anisotropies in mechanical properties of 3D printed composites. First, the properties vary greatly among parts made from different printers. Secondly, the mechanical responses of 3D printed parts strongly depend upon the orientations of the filaments. Parts with the infill oriented along the length of the specimens showed the most favorable mechanical responses such as Young’s modulus, maximum strength, and toughness. Thirdly, all 3D printed parts exhibit inferior properties to those made by conventional manufacturing. Finally, theoretical modeling has been attempted to predict the mechanical responses of 3D printed products and can potentially be used to “design” the 3D printing processes to achieve the optimal performance.

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