Bioinspired engineering polymers by voxel-based 3D-printing

Swetly, Theresa; Stampfl, Jürgen; Kempf, G.; Hucke, Rainer-Michael; Willing, Marcus; Warkentin, Marina

doi:10.1515/bnm-2015-0021

Cited by 9 publications

(5 citation statements)

References 26 publications

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“…DMA provided valuable information about the material behavior over a wide range of temperature. Parameters achieved were storage modulus, closely connected to the Young’s modulus, loss modulus representing the dissipated energy, and the dissipation factor which was connected to both storage and loss modulus, indicating the glass transition temperature of the sample [ 56 ].…”

Section: Methodsmentioning

confidence: 99%

Bio-Inspired Toughening of Composites in 3D-Printing

et al. 2020

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Natural materials achieve exceptional mechanical properties by relying on hierarchically structuring their internal architecture. In several marine species, layers of stiff and hard inorganic material are separated by thin compliant organic layers, giving their skeleton both stiffness and toughness. This phenomenon is fundamentally based on the periodical variation of Young’s modulus within the structure. In this study, alteration of mechanical properties is achieved through a layer-wise build-up of two different materials. A hybrid 3D-printing device combining stereolithography and inkjet printing is used for the manufacturing process. Both components used in this system, the ink for jetting and the resin for structuring by stereolithography (SLA), are acrylate-based and photo‑curable. Layers of resin and ink are solidified separately using two different light sources (λ1 = 375 nm, λ2 = 455 nm). Three composite sample groups (i.e., one hybrid material, two control groups) are built. Measurements reveal an increase in fracture toughness and elongation at break of 70% and 22%, respectively, for the hybrid material compared to the control groups. Moreover, the comparison of the two control groups shows that the effect is essentially dependent on different materials being well contained within separated layers. This bio-inspired building approach increases fracture toughness of an inherently brittle matrix material.

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Section: Methodsmentioning

confidence: 99%

Bio-Inspired Toughening of Composites in 3D-Printing

et al. 2020

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“…The explanation for this unexpected behaviour can be found in the scanning electron microscopy images of the corresponding fracture surfaces of SLA-parts. The fracture surfaces are typical for materials with low ductility with no signs of plastic deformation on the fracture surfaces [6]. Mechanical properties of AMT materials show the phenomenon of anisotropy.…”

Section: Introductionmentioning

confidence: 98%

Toughening of Photopolymers for Stereolithography (SL)

Dorfinger

Stampfl

Liska

2015

MSF

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Additive Manufacturing (AM) received a lot of attention in the last years. Organizations are using AM systems for a range of applications such as prototypes for fitting an assembly, tooling components, patterns for prototype tooling, functional parts and many more. Nearly a third is applied for functional parts [1][2]. Hence, the SL method provides a smoother surface finish than other AMT[3]. Not only is the smoother surface a benefit but the good precision is also a positive feature. The ongoing development of new material systems and applications make them suitable alternatives for conventional series production like injection molding or machined-core fabrication for foundry use. Small to middle series cores for faucets with quantities from around 50,000 pieces produced using AM methods are already a reality [1]. From the economical point of view, the SL is a cheap and fast process in comparison to AM systems. The SL technology used in this work is based on an active mask exposure, the digital light processing (DLP). The term DLP refers to the digital mirror devices which are used for selectively tuning individual mirrors on and off in order to selectively expose a photosensitive resin with visible or ultraviolet light. The resin contains a photoinitiator which triggers radical polymerization when irradiated with light. The polymerization process leads to a solidification of the resin, leading finally to a solid polymer part [4]. A digital Mirror Device (DMD) chip acts as a dynamic mask to expose a defined area on the bottom of a transparent material vat above the optical system. The generated picture enables layer-wise polymerization of the photosensitive resin resulting in a 3-dimensional object. The light source radiates light with a wavelength of 460 nm which means blue visible light. At this wavelength the curing takes place. At the Institute of Materials Science and Technology at the Vienna University of Technology six generations of these Blueprinter machines have been developed and built to date. The largest parts that a Blueprinter can currently generate are 110 x 110 x 80 mm3 with a resolution of 25 x 25 x 25 μm3. The wall thickness can go down to four pixels which means one tenth of a millimetre.

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“…By varying materials of individual voxels, the authors explored the material properties including elastic modulus, coefficient of thermal expansion, ductility, among others, attainable using a voxel-based fabrication process. Furthermore, Swetly et al (2016) studied the impact strength of voxel-based 3D printed parts. Fabricated parts were 50% stiff and 50% elastomer-like with the voxels arranged in a chessboard pattern and aligned at different voxel edge lengths.…”

Section: Introductionmentioning

confidence: 99%

Prediction and validation of composite mechanical properties resulting from voxel-based microstructural design in material jetting

Kaweesa

Bobbio

Beese

et al. 2022

RPJ

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Purpose This study aims to investigate the tensile strength and elastic modulus of custom-designed polymer composites developed using voxel-based design. This study also evaluates theoretical models, such as the rule of mixtures, Halpin–Tsai model, Cox–Krenchel model and the Young–Beaumont model and the ability to predict the mechanical properties of particle-reinforced composites based on changes in the design of rigid particles at the microscale within a flexible polymer matrix. Design/methodology/approach This study leverages the PolyJet process for voxel-printing capabilities and a design of experiments approach to define the microstructural design elements (i.e. aspect ratio, orientation, size and volume fraction) used to create custom-designed composites. Findings The comparison between the predictions and experimental results helps identify appropriate methods for determining the mechanical properties of custom-designed composites ensuring informed design decisions for improved mechanical properties. Originality/value This work centers on multimaterial additive manufacturing leveraging design freedom and material complexity to create a wide range of composite materials. This study highlights the importance of identifying the process, structure and property relationships in material design.

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Bioinspired engineering polymers by voxel-based 3D-printing

Cited by 9 publications

References 26 publications

Bio-Inspired Toughening of Composites in 3D-Printing

Bio-Inspired Toughening of Composites in 3D-Printing

Toughening of Photopolymers for Stereolithography (SL)

Prediction and validation of composite mechanical properties resulting from voxel-based microstructural design in material jetting

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