Manufactured Acrylonitrile Butadiene Styrene Research Articles

Experimental and theoretical investigation of the influence of post-curing on mixed mode fracture properties of 3d-printed polymer samples

This study explores the mechanical properties and fracture characteristics of additively manufactured acrylonitrile butadiene styrene specimens, focusing on the impact of raster angle and post-process heat treatment. To this end, a large number of tensile and semi-circular bending samples with three distinct raster angles of 0/90°, 22/ − 68°, and 45/ − 45° were prepared and exposed to four types of heat treatments with different temperature and pressure conditions. Simultaneously, theoretical models of maximum tangential stress (MTS) and generalized MTS (GMTS) were developed to estimate the onset of specimen fracture under mixed-mode in-plane loading conditions. Recognizing the non-linear behavior within the stress–strain curve of tensile test samples, particularly in the annealed samples, an effort was undertaken to transform the original ductile material into a virtual brittle material through the application of the equivalent material concept (EMC). This approach serves the dual purpose of bypassing intricate and tedious elastoplastic analysis, while concurrently enhancing the precision of the GMTS criterion. The experimental findings have revealed that while the annealing process has a minimal effect on the yield strength, it considerably enhances energy absorption capacity, increases fracture toughness, and reduces the anisotropy. Additionally, the combined EMC-GMTS criterion has demonstrated its capability to predict the failure of the additively manufactured parts with an acceptable level of accuracy.

Rheology and thermomechanical evaluation of additively manufactured acrylonitrile butadiene styrene (ABS) with optimized tungsten carbide (WC) nano-ceramic content

Tungsten carbide (WC), a superhard and thermally stable ceramic, is widely used in several industries. Its exceptional features portray WC as a promising reinforcement and stabilizing agent for popular polymeric matrices deployed in material extrusion (MEX) 3D-Printing, such as Acrylonitrile Butadiene Styrene (ABS). This potential was investigated in depth and is presented herein. ABS/WC nanocomposite filaments were prepared by melt extrusion and tested. A filler loading of 0 wt % up to 10 wt % WC, in 2 wt % steps were fabricated. The impact of the WC nanopowder content on the structural, rheological, thermal, mechanical, and morphological characteristics of nanocomposite filaments and 3D printed samples was investigated with the aid of fifteen (15) different tests. The experiments revealed excellent thermal stability of the developed nanocomposites, as well as non-Newtonian shear thinning behavior of their melts, which is encouraging for their processability. WC nanoparticles impressively upgraded the mechanical capacity of the optimized nanocomposites in comparison to that of pure ABS. ABS with 4.0 wt % WC grade exhibited a noticeable increase in most of the mechanical characteristics; Compressive, flexural, and tensile strength all rose by 25.9%, 29.4%, and 20.9% respectively, while the microhardness increased by 100.3%, showing potential for use in applications requiring high wear resistance. The findings of the current research indicate that novel cost-effective ABS/WC composites have high potential and industrial merit for a variety of demanding applications with ABS-based composites.

Machine learning model for predicting the hardness of additively manufactured acrylonitrile butadiene styrene

Additive manufacturing is an incipient technology with great potential to achieve excellent mechanical properties with minimal material wastage. Additive manufacturing is well known for its quick fabrication of end-use components. The process parameter described during slicing process will influence the mechanical properties of the additively fabricated components. In this present study, machine learning models such as linear regression, decision tree, random forest, adaboost were used to optimize the process parameters and to predict hardness value for other process parameters. Machine learning models such as linear regression, decision tree, random forest, and adaboost were used to predict the output response. These models were selected to illustrate the variance in performance of various kinds of machine learning model on real-time experimental data. The test specimens were fabricated through fused filament fabrication (FFF). Acrylonitrile Butadiene Styrene (ABS) is an engineering thermoplastic used as a feedstock material. The hardness values were determined using a shore D durometer, which is specifically meant to measure the hardness of plastics and rubbers. The design of experiments was evaluated by considering four parameters at three different levels. Infill density, layer thickness, print orientation, and raster orientation are the four parameters, which was taken into account. The robustness and acceptability of four different machine learning models were evaluated at various error metrics. From the results, the adequacy of random forest model is highlighted over other machine learning models. From observation, the value of the co-efficient of determination(R2) for various models ranged from 0.8437 to 0.9136, with the random forest model ranking the highest (0.9136). This research will be helpful in predicting the level of input parameters needed to obtain the maximum hardness of ABS material.

Conductive Additive Manufactured Acrylonitrile Butadiene Styrene Filaments: Statistical Approach to Mechanical and Electrical Behaviors.

Additive manufacturing is a process in which digital three-dimensional (3D) design data are used to build a component in layers by accumulating materials. There are many materials used in additive manufacturing technology. The most basic features that distinguish these materials are their strength and electrical behavior. They can be strong or flexible, resistant to abrasion, depending on the application used. Recently, 3D printing filament and polymeric composite materials combined with carbon nanostructures with electrical conductivity have been used. In this study, acrylonitrile butadiene styrene (ABS), a carbon black-filled conductive material with high strength and hardness, was preferred. The aim in this study is to focus on the mechanical and electrical behavior of the material processed in filament form. Fabrication of samples was done using a fused deposition modeling-based printer that controls filament orientation. Different experimental studies were conducted: (1) mechanical tests to determine the maximum tensile strength values of the samples; and (2) electrical tests to analyze the electrical resistances of the samples. In the design of the first experiment, infill volume, layer height, infill type, and printing direction were determined as factors affecting strength. In the design of the second experiment, the length, nozzle temperature, and measurement temperature were determined as the factors affecting the electrical resistance. Statistical analysis of the measured data was performed to evaluate the overall result of the experiments. Finally, a prediction model of real-time tensile strength and resistance values was created using machine learning algorithms. These algorithms are Gaussian Process Regression and Support Vector Machine. The results confirmed the known linear dependence of electrical resistance on the length of the 3D-printed conductive ABS samples and showed how changing the fabrication settings affected the strength values.

Viscoelastic characterization of additively manufactured acrylonitrile butadiene styrene

Viscoelastic characterization of additively manufactured acrylonitrile butadiene styrene

Predicting Material Properties of Additively Manufactured Acrylonitrile Butadiene Styrene via a Multiscale Analysis Process.

Additive manufacturing (AM) has inherent mechanical strength inconsistencies when the build orientation changes. To address this issue, theoretical models, including analytical and numerical models, can be developed to predict the material properties of additively manufactured materials. This study develops a systematic finite element (FE)-based multiscale numerical model and simulation process for the polymer acrylonitrile butadiene styrene (ABS). ABS samples are fabricated using fused deposition modelling (FDM) to determine the material properties and mechanical behaviours. For macroscale analysis, good agreement between the numerical and experimental tensile strength of transverse samples proved that the FE model is applicable for applying a reverse engineering method in simulating the uniaxial tension of samples. The FE modelling method shows its capability to consider infill density effects. For mesoscale analysis, two methods are developed. The first method is a representative volume element (RVE)-based numerical model for all longitudinal samples. The second method is analytical and based on the rule of mixtures (ROM). Modified rule of mixtures (MROM) models are also developed, which demonstrate an improvement compared to the original ROM models. The research outcomes of this study can facilitate the AM process of parts in various engineering fields.

Effect of Shear Angle and Printing Orientation on Shear Constitutive Response of Additively Manufactured Acrylonitrile Butadiene Styrene.

An experimental investigation was performed to understand the quasi-static shear response of additively manufactured (AM) acrylonitrile butadiene styrene (ABS) via fusion deposition modeling (FDM). A modified flat hat-shaped (FHS) specimen configuration was used for shear testing. The main aim of this study was to investigate the effect of four different shear angles (0°, 5.44°, 13.39°, and 20.83°) and three printing orientations (vertical build, 0°/90°, and 45°/−45°) on the shear constitutive response and shear performance of FDM-printed ABS. Scanning electron microscopy images of the failure surface were used to explain the shear response of the material. The flow shear stress of the shear stress-strain response for vertically printed specimens demonstrated a monotonic increase up to a peak shear stress and then decrease at the end of the shear zone, while for 0°/90° specimens, an increasing trend until the peak value at the end of the shear zone was observed. With increasing shear angles, all specimens printed with three printing orientations exhibited increasing shear zone size and shear strength, and the 0°/90° specimens exhibited the highest shear strength for all four shear angles. However, the specimens of the 45°/−45° orientation demonstrated the highest increase in shear strength by about 60% and in the shear strain at the end of shear zone by about 175% as the shear angle was increased from 0° to 20.83°.

Photovoltaic Industrial Waste as Substitutional Reinforcement in the Preparation of Additively Manufactured Acrylonitrile Butadiene Styrene Composite

Photovoltaic Industrial Waste as Substitutional Reinforcement in the Preparation of Additively Manufactured Acrylonitrile Butadiene Styrene Composite

Incorporation of fiber Bragg grating sensors in additive manufactured Acrylonitrile butadiene styrene for strain monitoring during fatigue loading

This study investigates the characteristics of Fiber Braggs Grating (FBG) sensors with respect to their feasibility for use in additive manufactured materials under fatigue loading. This was done through tensile fatigue testing of both standard Acrylonitrile butadiene styrene (ABS) specimens and ABS specimens containing FBG sensors. These sensors were incorporated into the material using two different techniques: inserting and embedding. Comparing fatigue test results between the specimen types showed that incorporating the FBGs into the material affected fatigue life differently depending on the load level, while also increasing the variation in fatigue life between specimens. The strain measurements of the embedded FBGs were seen to more closely resemble results from finite element simulations than were the measurements of the inserted FBGs, thus proving embedding to be the superior technique.

Effects of Size and Surface Treatment on Fatigue Life of Fused Filament Fabrication Manufactured Acrylonitrile Butadiene Styrene Parts

Abstract An experimental study was conducted to study the effects of geometric size and surface treatment on the fatigue life of fused filament fabrication (FFF) manufactured acrylonitrile butadiene styrene (ABS) parts. Moore rotating-beam fatigue tests were conducted with four different levels of loadings to obtain the S–N curves. Two different sizes (control size and large size) and three different surface treatment methods (as-printed, acetone-treated, and sandpaper polished) were studied. The larger specimens had significantly decreased fatigue life because of a larger volume, and hence a greater probability of defects for crack initiation and propagation, as compared with the control specimen. The acetone-treated specimen had a smooth surface. Its fatigue life, however, decreased significantly because the acetone treatment caused internal damage that weakened the specimen and was reported for the first time. The sandpaper polished specimen also had a smooth surface, but its effect on the fatigue life was insignificant because the extruded filament direction on the specimen surface was parallel to the loading direction. The present results lead to a better understanding of the effects of geometric size and surface treatment on the fatigue performance of FFF specimens. The study also provides important insights for the design of part size and surface treatment of three-dimensional (3D) printed plastic components for fatigue loading end-use applications.

Analysis of Notch Effect in 3D-Printed ABS Fracture Specimens Containing U-Notches.

In this paper a fracture assessment in additive manufactured acrylonitrile butadiene styrene (ABS) fracture specimens containing U-notches is performed. We performed 33 fracture tests and 9 tensile tests, combining five different notch radii (0 mm, 0.25 mm, 0.50 mm, 1 mm and 2 mm) and three different raster orientations: 0/90, 30/−60 and 45/−45. The theory of critical distances (TCD) was then used in the analysis of fracture test results, obtaining additional validation of this theoretical framework. Different versions of TCD provided suitable results contrasting with the experimental tests performed. Moreover, the fracture mechanisms were evaluated using scanning electron microscopy in order to establish relationships with the behaviour observed. It was demonstrated that 3D-printed ABS material presents a clear notch effect, and also that the TCD, through both the point method and the line method, captured the physics of the notch effect in 3D-printed ABS. Finally, it was observed that the change in the fracture mechanisms when introducing a finite notch radius was limited to a narrow band behind the original defect, which appeared in cracked specimens but not in notched specimens.

Friction and wear of additive manufactured polymers in dry contact

• The friction and wear mechanism of additively manufactured Polyjet parts are investigated. • The tribological dependence on applied load at 1N, 5N and 10N is studied. • The highest coefficient of friction is observed under 1N load for both parallel and perpendicular orientations. • Wear rate in Polyjet parts is influenced by the surface orientation to the sliding direction and applied load. The use of additive manufacturing (AM) is widely advancing the scope of rapid prototyping and manufacturing in tribological applications and material science research. However, there is still limited research focused on investigating the frictional and wear performance of AM polymers, especially of Polyjet manufactured parts. This work focuses on the effect of varying the contact load on the friction and wear mechanisms of additively manufactured acrylonitrile butadiene styrene (3D ABS) and Verogray polymers fabricated using Polyjet technology. Loads of 1, 5 and 10 N were applied under dry sliding contact with a 52100 steel counterface at room temperature. Dependence of friction and wear on the surface orientation to the sliding direction is noted. The results demonstrate that at 1 N load, the friction coefficient is primarily dependent on the orientation of the surface to the sliding direction. However, at higher loads of 5 N and 10 N, this dependency is shown to be a function of the bulk material properties rather than the surface roughness. Further correlation between the surface morphology and wear rate is shown to be dependent on the bulk material properties and the applied load. The results from this study provide alternate application uses for Polyjet materials in metal-polymer tribo-contacts for improved friction and wear performance.

Effect of recycling on the mechanical behavior and structure of additively manufactured acrylonitrile butadiene styrene (ABS)

Fused deposition modeling (FDM) is the most common additive manufacturing system that is increasingly used for industrial and consumer applications. These systems selectively extrude/deposit polymers to manufacture parts directly from computational designs. Therefore, FDM enables conversion of recycled thermoplastic polymers to higher quality products. However, FDM induces porosity, which reduces mechanical performance and causes variations in mechanical properties of fused deposition modeled (FDMed) polymers. A safe and reliable use of FDMed-recycled polymers demands a better understanding of the effect of recycling on the mechanical properties. In this study, we investigated the effect of three rounds of recycling on the stochastic mechanical properties of FDMed ABS. A total of 337 tensile tests were performed on FDMed virgin and recycled ABS. Recycling increased the porosity of FDMed ABS from ∼11 vol% to ∼17 vol %. The tensile and fracture strength decreased by ∼10%. The strain at break decreased by 25% from 5.2% to 3.9%, causing a decrease in toughness by 37%. We observed significant variations in the mechanical properties, which were analyzed using Weibull statistics. An S-type deviation from Weibull distribution was observed for strength variations that was related to porosity. Minimal degradation in ABS molecular structure was observed via gel permeation chromatography, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. X-ray fluorescence spectroscopy revealed an increase in elemental iron with recycling.

On-Load Characteristics of Local and Global Forces in Co-Axial Magnetic Gear with Reference to Additively Manufactured Parts of Modulator

The paper presents an analysis of local and global forces acting on the ferromagnetic material of a modulator in a co-axial magnetic gear, taking several design variants and the impact of loading into account. The analyses include a modulator with cores manufactured from a soft-magnetic composite material and two variants made from electrical steel with laminations stacked in different directions. Variations of local forces acting on individual pole pieces of the modulator are analyzed at different loads, showing that the force spectra are subject to significant variation with an increasing load. The presented magnetostatic analyses are extended by structural analysis that provides estimation of stress and displacement for the modulator assembled from additively manufactured acrylonitrile butadiene styrene (ABS)-plastic parts. The analysis carried out for the least favorable design case of the magnetic circuit of the modulator shows that an application of the technology is significantly restricted by the magnetic gear torque volumetric density. Some changes to the modulator mechanical design are proposed in the paper to mitigate the drawbacks of this technology.

Notch static strength of additively manufactured acrylonitrile butadiene styrene (ABS)

The present theoretical/experimental investigation deals with the problem of performing the static assessment of notched components made of additively manufactured Acrylonitrile Butadiene Styrene (ABS). The notch strength of this 3D-printed material was investigated by testing a large number of specimens, with the experiments being run not only under tension, but also under three-point bending. The samples contained geometrical features of different sharpness and were manufactured (flat on the build plate) by changing the printing direction. Being supported by the experimental evidence, the hypothesis was formed that the mechanical response of 3D-printed ABS can be modelled effectively by treating it as a material that is linear-elastic, brittle, homogenous and isotropic. This simplifying hypothesis allowed the Theory of Critical Distances to be employed also to assess static strength of 3D-printed ABS containing geometrical features. The validation exercise based on the experimental results being generated demonstrates that this theory is highly accurate, with its use leading to predictions falling mainly within an error interval of about ±20%. This level of accuracy is certainly satisfactory especially because this static assessment methodology can be used in situations of engineering relevance by making use of the results obtained by solving standard linear-elastic Finite Element models.

Static assessment of notched additively manufactured acrylonitrile butadiene styrene (ABS)

The present paper tackles the problem of performing the static assessment of notched additively manufactured (AM) acrylonitrile butadiene styrene (ABS) components. A large number of ABS specimens containing different notch profiles and sharpness were manufactured (flat on build plate) by varying the printing angles to simulate the stress concentration phenomena. These specimens were tested under tension and three-point bending to generate a large amount of experimental data. From the experimental results, it is evident that the AM ABS materials can simply be modelled as an elastic, brittle, homogenous and isotropic material. This simplification allowed the application of the Theory of Critical Distances (TCD) to become a viable static assessment tool for the AM ABS components. As a result, it was proven that the TCD is an accurate and valid static assessment tool for the AM ABS components with estimations mainly falling within an error interval of about ±20%. This result is certainly rewarding from an engineering application perspective as the TCD successfully enables engineers to assess the static strength of additively manufactured engineering components that contain intricate geometrical features accurately, rapidly, and economically.

Crack Propagation in Flexural Testing of Additive Manufactured Acrylonitrile Butadiene Styrene

Fused Deposition Modelling (FDM) is one of the most important Additive Manufacturing (AM) technologies. This is a technology suitable for various engineering applications and currently used with many types of thermoplastic materials including Acrylonitrile Butadiene Styrene (ABS). AM-FDM printed ABS possesses an inherent capacity for property modifications as a function of printing parameters. The main goal of the present ongoing research project is to estimate the strength of the AM-FDM printed ABS for varying printing process parameters. In the present study, the mechanical and structural characterizations of AM-FDM ABS were evaluated by light microscopy and mechanical testing. Three-point bend flexural test results revealed the mechanical properties as well as the fracture behaviour according to the dimensions and printing strategies of the build-on specimens. An innovative transmitted-light microscopy experimental method was developed and utilized to investigate the crack propagation behaviour under bending.

Mechanical, electrical, and piezoresistivity behaviors of additively manufactured acrylonitrile butadiene styrene/carbon nanotube nanocomposites

Tensile, fracture, electrical, and piezoresistivity behaviors of additively manufactured acrylonitrile butadiene styrene (ABS)/carbon nanotube (CNT) nanocomposites were investigated. Filaments with CNT contents up to 10 wt% were fabricated using a twin-screw extruder and 3D printed through fused filament fabrication (FFF). The printed ABS samples showed similar or better strength, stiffness, and strain-at-break values, compared to those of compression-molded counterparts. The strength and stiffness of the printed ABS were significantly enhanced by introducing CNT, with an optimum content of ∼3.0–5.0 wt%. The ductile fracture behavior and high fracture resistance (KIc = 2.2–2.4 MPa m1/2 and GQ = 3 kJ m−2) of ABS was maintained in the nanocomposites with a maximum CNT content of 3.0 wt%, beyond which it decreased significantly. The printed samples’ conductivity was at least one order of magnitude lower than that of the compression-molded ones. Moreover, the in-layer conductivity was about two orders of magnitudes higher than the through-layer one, introducing a noticeable anisotropy at lower CNT contents. The piezoresistivity tests revealed a relatively linear resistance–strain relationship for the elastic region. A sudden change in the resistance was also detected at the onset of plastic deformation. These variations in the mechanical and electrical behaviors were explained in terms of the CNT agglomerates, CNT alignment, interlayer bond quality, and the inter-raster voids.

A Novel Approach to Increase Dynamic Fracture Toughness of Additively Manufactured Polymer

An experimental study is performed to investigate the dynamic fracture of additive manufactured Acrylonitrile Butadiene Styrene (ABS). A single edge notched bending (SENB) specimen with three orientations, namely horizontal builds with 45°/−45° (H45), 0°/90° (H90) raster orientations, and vertical builds with layers perpendicular to the pre-crack (V0) are considered for this study. In addition, a novel toughening mechanism is explored by changing the surface topology to deflect the crack paths. A modified split Hopkinson pressure bar with a copper pulse shaper (to increase the raising time of incident loading pulse) is used to conduct a three-point bend impact experiment to characterize the dynamic fracture initiation toughness and crack dynamics of 3D printed specimens. Real-time crack initiation and propagation is captured by using a high-speed video camera. Using the load history diagram, accurate fracture initiation load is found to determine dynamic fracture initiation toughness. Fracture initiation toughness is increased by 138% for a V0 specimen configuration compared to H90. Three different sized circular patterns (with diameters of 1, 1.75 and 2.5 mm) and a square pattern (with a length of 1.53 mm) are considered to observe the effect of surface topology on the dynamic fracture initiation toughness. Introducing surface pattern to the specimen increases the fracture toughness by 58% as compared to specimens without surface pattern. Surface pattern also exhibits two steps of crack growth and decreases the initial crack propagation velocity significantly for all three orientations. Additionally, higher fracture initiation toughness is achieved with the increase in the size of the pattern and the change of the pattern shape.

Crazing in additively manufactured acrylonitrile butadiene styrene

Additively manufactured acrylonitrile butadiene styrene (ABS) via fused deposition modeling (FDM) and compression molded ABS specimens were loaded in tension to compare their crazing behavior. Crazes in the compression molded ABS appeared simultaneously and uniformly across the entire cross section of the specimens after the crazing stress threshold was reached. Crazing in the FDM ABS was found to be driven by the large internal voids, artifacts of the FDM fabrication process. Crazes in FDM ABS initiated at a single initiation site and were significantly thicker in size. Micro Computed Tomography scans of the FDM ABS specimens before and after crazing showed that crazes initiated at internal voids, and the voids increased in size as the crazes propagated through the specimens.