Properties Of 3D Printed Materials Research Articles

Combined effect of heating temperature and content of pectin on the textural properties, rheology, and 3D printability of potato starch gel

Three-dimensional (3D) printing is one of the emerging techniques which fabricates customized foods with desired sensory characteristics. Rheological properties of 3D printing materials are vitally important in printability which govern the flowability and structural stability. Due to its unique gel-forming characteristics, potato starch has been extensively used in myriad food applications, such as 3D printing. However, little attention has been paid to the combined effect of heating temperature and pectin addition on the properties of potato starch gels. Thus, this study investigated the impact of different pectin contents (1, 1.5, and 2 %) on printability and the rheological and textural properties of potato starch gels heated at different temperatures (70, 80, and 90 °C). The gel heating temperature governs pectin-driven modifications in potato starch gels. Pectin addition increased the 3D printability, viscosity, storage modulus, hardness, gumminess, and springiness of starch gel at higher temperatures (80 °C and 90 °C). In contrast, at lower temperatures (70 °C), pectin addition decreased printability, viscosity, storage modulus, hardness, gumminess, and springiness. Therefore, the gel heating temperature influences the impact of pectin on printability, rheology, and textural properties. Accordingly, the combined effects of pectin and heating temperature should be considered in pectin-based 3D food-printing ink formulations.

A finite element model for 3D printed recycled parts from end-of-life wind turbine blades

Wind turbines are important for clean electric energy, but the increasing number of end-of-life wind turbine blades has become a hazardous waste problem worldwide. A novel recycling approach based on mechanical grinding and combined with 3D printing techniques is a promising solution that will reduce waste at a low cost while retaining the excellent mechanical properties of recycled fabricated samples.Considering the material structure complexity of 3D printed samples, the Representative Volume Element (RVE) is a promising simulation model. This paper proposes a Modified Random Sequential Adsorption (MRSA) algorithm for the efficient generation of RVEs with hybrid and arbitrary-geometry reinforcements. Compared with the classical RSA algorithm, MRSA is advantageous in fiber intersection computational cost. The error between FEA and experiments is lower than results obtained from Mori-Tanaka and Halpin-Tsai. The effects of fiber content, fiber aspect ratio, fiber orientation and local fiber density are discussed. The model will be helpful for accurately predicting properties of 3D printing materials that use recycled wind turbine waste.

An Investigation of the Properties of 3D Printing Materials According to Additive Manufacturing Conditions Using Ultrasonic Wave

An Investigation of the Properties of 3D Printing Materials According to Additive Manufacturing Conditions Using Ultrasonic Wave

Design principles for a single-process 3D-printed stacked dielectric actuators — Theory and experiment

Fully 3D-printed smart structures have attracted a lot of research interest; new technologies, materials, and methods for 3D-printed functional structures such as sensors, actuators, generators, and batteries are being researched. Recently, a fully 3D-printed, dynamic dielectric actuator fabricated in a single process with multi-material thermoplastic filament extrusion was presented. However, the effects of design parameters on the dynamic electromechanical properties of the printed actuator were not yet researched.To achieve the required performance and dynamic properties of an individualized, 3D-printed actuator, the electromechanical properties must be related to the theoretical design parameters. This requires research into the properties of 3D-printed materials and the electromechanical modeling of the 3D-printed actuator.In this research, an analytical, electromechanical model is introduced, consisting of electrical and mechanical models, and electromechanical coupling. The model consists of basic electrical and dynamic lumped elements, which facilitates the reproducibility and extensibility of the model. The electrical and electromechanical model have been experimentally validated in a free-displacement and a blocked-force boundary condition.This research leads to the identification of design principles and the ability to customize and adapt the 3D-printed actuators to specific dynamic applications.

Comprehensive study of 3D printing materials over the terahertz regime: absorption coefficient and refractive index characterizations

Generation of terahertz (THz) radiation has become increasingly accessible over time. The research and development of THz applications is ongoing, often requiring the use of THz compatible optical components. At the same time, rapid prototyping three-dimensional (3D) printing systems are now commercially accessible and are capable of printing resolutions on the order of the THz wavelengths. Thus, 3D printing systems can be leveraged for use in creating novel THz optical components in varied experiments and applications. The filament material used in 3D printing systems dictates the absorptive and refractive properties of the 3D printed THz optical component. The commercial release of filament materials is continuous, year after year, inducing a need for literature to stay current with characterizing these filament materials over the THz gap. We use terahertz time-domain spectroscopy (THz-TDS) to characterize the absorptive and refractive properties of 3D printing materials over the THz gap. We present a consolidative and comprehensive aggregation of THz-TDS measurements of twenty-three 3D printing materials. A comparison of THz-TDS measurements for thick and thin samples provides verification of measurement accuracy. The measured THz bandwidth of these samples is extended by up to 1.2 THz. Furthermore, to the authors’ best knowledge, the proposed work puts forward the first THz-TDS measurements of polyvinyl butyral, polyetherimide, and low temperature polycaprolactone filament materials. This work primarily focuses on fused deposition modeling (FDM) 3D printed materials, rather than stereolithography (SLA) 3D printed materials.

Influence of wettability and surface design on the adhesion of terrestrial cyanobacteria to additive manufactured biocarriers

Productive biofilms are gaining growing interest in research due to their potential of producing valuable compounds and bioactive substances such as antibiotics. This is supported by recent developments in biofilm photobioreactors that established the controlled phototrophic cultivation of algae and cyanobacteria. Cultivation of biofilms can be challenging due to the need of surfaces for biofilm adhesion. The total production of biomass, and thus production of e.g. bioactive substances, within the bioreactor volume highly depends on the available cultivation surface. To achieve an enlargement of surface area for biofilm photobioreactors, biocarriers can be implemented in the cultivation. Thereby, material properties and design of the biocarriers are important for initial biofilm formation and growth of cyanobacteria. In this study, special biocarriers were designed and additively manufactured to investigate different polymeric materials and surface designs regarding biofilm adhesion of the terrestrial cyanobacterium Nostoc flagelliforme (CCAP 1453/33). Properties of 3D-printed materials were characterized by determination of wettability, surface roughness, and density. To evaluate the influence of wettability on biofilm formation, material properties were specifically modified by gas-phase fluorination and biofilm formation was analyzed on biocarriers with basic and optimized geometry in shaking flask cultivation. We found that different polymeric materials revealed no significant differences in wettability and with identical surface design no significant effect on biomass adhesion was observed. However, materials treated with fluorination as well as optimized biocarrier design showed improved wettability and an increase in biomass adhesion per biocarrier surface.

Non-destructive Analysis of the Mechanical Properties of 3D-Printed Materials

The determination of the mechanical properties of materials is predominantly undertaken using destructive approaches. Such approaches are based on well-established mathematical formulations where a physical property of the material is measured as a function of an input under controlled conditions provided by some machine, such as load–displacement curves in indentation tests and stress–strain plots in tensile testing. The main disadvantage of these methods is that they involve destruction of samples as they are usually tested to failure to determine the properties of interest. This means that large sample sizes are required to obtain statistical certainty, a condition that, depending on the material, may mean the process is both time consuming and expensive. In addition, for rapid prototyping and small-batch manufacturing of polymers, these techniques may be inappropriate either due to excessive cost or high polymer composition variability between batches. In this paper we discuss how the Euler–Bernoulli beam theory can be exploited for experimental, non-destructive assessment of the mechanical properties of three different 3D-printed materials: a plastic, an elastomer, and a hydrogel. We demonstrate applicability of the approach for materials, which vary by several orders of magnitude of Young’s moduli, by measuring the resonance frequencies of appended rectangular cantilevers using laser Doppler vibrometry. The results indicate that experimental determination of the resonance frequency can be used to accurately determine the exact elastic modulus of any given 3D-printed component. We compare the obtained results with those obtained by tensile testing for comparison and validation.

Investigation of the material mixtures and fiber addition for 3D concrete printing

The era of Construction 4.0 is characterized by technological advances used in the construction industry. One of the advancements is the use of 3D concrete printing in construction. However, until now, the development of 3D concrete printing in Indonesia is still minimal. The main challenge is to determine the composition of the material mixtures for making the mortar, having good extrudability but still has sufficient strength. The rapid initial setting time required was also different for the concrete for typical construction. Our previous mixture composition incorporating calcium oxide to accelerate the initial setting time was adequate. However, the extrusion process was still not satisfactory. In this study, the effect of cement to sand ratio, sand particle size, and the addition of synthetic micro-fiber was investigated on the main properties of 3D printing materials, i.e., initial setting time, flowability, extrudability, and compressive strength. It was found that using smaller maximum particle size sand increases the initial setting time. The addition of synthetic microfiber reduces the strength and the workability of the mortar. However, fiber inclusion has advantages as it reduces the possibility of cracking in the printed concrete. The extruded concrete specimens were shown to have significant strength reduction due to lack of compaction, and it was affected by the direction of printing showing orthotropic properties of the 3D printed concrete.

Research progress of 3D printing materials in stomatology

3D printing technology is gradually used in the field of stomatology, such as repair, planting, orthodontics and other disciplines. 3D printing process mainly includes four aspects: oral scanning, Digital design, 3D printing materials and 3D printing technology and equipment. The properties of 3D printing materials are the key factors affecting the effect of 3D printing. This paper reviews the research and development of 3D printing materials in stomatology at home and abroad in recent years and prospects the future development of 3D printing materials in that field.

A method to predict the ultimate tensile strength of 3D printing polylactic acid (PLA) materials with different printing orientations

3D Printing is widely used in scientific researches and engineering applications, ranging from aerospace to biomedicine. However little is known about the mechanical properties of 3D printing materials. In order to promote the mechanical analysis and design of 3D printing structures, the ultimate tensile strength of FDM PLA materials with different printing angles were studied theoretically and experimentally. A theoretical model was firstly established to predict the ultimate tensile strength of FDM PLA materials based on transverse isotropic hypothesis, classical lamination theory and Hill-Tsai anisotropic yield criterion, and then verified by tensile experiments. Compared with previous models, this model provided two kinds of in-plane shear modulus calculation methods, so the calculation results were more reliable. The specimens, designed according to the current plastic-multipurpose test specimens standard ISO 527-2-2012, were printed in seven different angles (0∘, 15∘, 30∘, 45∘, 60∘, 75∘, 90∘) with three layer thicknesses (0.1 mm, 0.2 mm, 0.3 mm) for each angle. The relative residual sum of squares between theoretical data and experimental data were all close to zero, so the results that the theoretical model can accurately predict the ultimate tensile strength of FDM materials for all angles and thicknesses were confirmed. It was also found that the ultimate tensile strength decreased as the printing angle becomes smaller or the layer becomes thicker. This theoretical model and experimental method can also be applied to other 3D printing materials fabricated by FDM or SLA techniques.

3D nyomtatási anyagok mechanikai tulajdonságainak meghatározása különböző nyomtatási irányokban

3D nyomtatási anyagok mechanikai tulajdonságainak meghatározása különböző nyomtatási irányokban

Radiological properties of 3D printed materials in kilovoltage and megavoltage photon beams

PurposeThis study evaluates the radiological properties of different 3D printing materials for a range of photon energies, including kV and MV CT imaging and MV radiotherapy beams. MethodsThe CT values of a number of materials were measured on an Aquilion One CT scanner at 80kVp, 120kVp and a Tomotherapy Hi Art MVCT imaging beam. Attenuation of the materials in a 6MV radiotherapy beam was investigated. ResultsPlastic filaments printed with various infill densities have CT values of −743±4, −580±1 and −113±3 in 120kVp CT images which approximate the CT values of low-density lung, high-density lung and soft tissue respectively. Metal-infused plastic filaments printed with a 90% infill density have CT values of 658±1 and 739±6 in MVCT images which approximate the attenuation of cortical bone. The effective relative electron density REDeff is used to describe the attenuation of a megavoltage treatment beam, taking into account effects relating to the atomic number and mass density of the material. Plastic filaments printed with a 90% infill density have REDeff values of 1.02±0.03 and 0.94±0.02 which approximate the relative electron density RED of soft tissue. Printed resins have REDeff values of 1.11±0.03 and 1.09±0.03 which approximate the RED of bone mineral. Conclusions3D printers can model a variety of body tissues which can be used to create phantoms useful for both imaging and dosimetric studies.