Raster Orientation Research Articles

Notch Effect in Acrylonitrile Styrene Acrylate (ASA) Single-Edge-Notch Bending Specimens Manufactured by Fused Filament Fabrication.

This paper analyses the notch effect in the fracture behaviour of acrylonitrile-styrene-acrylate (ASA) material manufactured by fused filament fabrication (FFF). The research is performed on 72 single-edge-notch bending (SENB) specimens containing U-notches with nominal notch radii varying from 0 mm (crack-like defects) up to 2.0 mm, and fabricated with three different raster orientations (0/90, 45/-45, 30/-60). Apparent fracture toughness values are obtained for the different conditions and the resulting notch effect is analysed through the Theory of Critical Distances. A fractographic analysis is also performed using Scanning Electron Microscopy (SEM) in order to justify the fracture (macroscopic) behaviour from the observed fracture micromechanisms. The notch effect observed in the three ASA raster orientations is very similar, and lower than that observed in other FFF polymeric alternatives (ABS, PLA).

Characterization of Thermal Expansion Coefficient of 3D Printing Polymeric Materials Using Fiber Bragg Grating Sensors.

This work aims at the determination of the coefficient of thermal expansion (CTE) of parts manufactured through the Fused Deposition Modeling process, employing fiber Bragg grating (FBG) sensors. Pure thermoplastic and composite specimens were built using different commercially available filament materials, including acrylonitrile butadiene styrene, polylactic acid, polyamide, polyether-block-amide (PEBA) and chopped carbon fiber-reinforced polyamide (CF-PA) composite. During the building process, the FBGs were embedded into the middle-plane of the test specimens, featuring 0° and 90° raster printing orientations. The samples were then subjected to thermal loading for measuring the thermally induced strains as a function of applied temperature and, consequently, the test samples' CTE and glass transition temperature (Tg) based on the recorded FBG wavelengths. Additionally, the integrated FBGs were used for the characterization of the residual strain magnitudes both at the end of the 3D printing process and at the end of each of the two consecutively applied thermal cycles. The results indicate that, among all tested materials, the CF-PA/0° specimens exhibited the lowest CTE value of 14 × 10-6/°C. The PEBA material was proven to have the most isotropic thermal response for both examined raster orientations, 0° and 90°, with CTE values of 117 × 10-6/°C and 108 × 10-6/°C, respectively, while similar residual strains were also calculated in both printing orientations. It is presented that the followed FBG-based methodology is proven to be an excellent alternative experimental technique for the CTE characterization of materials used in 3D printing.

Tensile fracture prediction of 3D-printed V-notched PLA specimens: Application of VIMC-MEMC in conjunction with brittle fracture criteria

This study investigates the fracture behavior of additively manufactured round-tip V-notched diagonally loaded square plate (RV-DLSP) specimens with different notch opening angles and tip radii produced from the Polylactic acid (PLA) with [0/90/45/-45]s raster orientation using the fused deposition modeling (FDM) technique. PLA is known for its ductile behavior, making it a suitable material for various engineering applications. Also, the layer-wise manufacturing process in FDM technique makes the PLA specimens be actually anisotropic. To take the nonlinearity and anisotropy of PLA simultaneously into consideration in prediction of the fracture loads of RV-DLSP specimens, the present study employs the Virtual Isotropic Material Concept (VIMC) and modified Equivalent Material Concept (MEMC) in a two-level strategy of simplifying PLA to an isotropic linear elastic virtual material. Then, the mean stress (MS) and maximum tangential stress (MTS) criteria are utilized to estimate the fracture loads. The theoretical estimations reveal that the VIMC-MEMC-RV-MS criterion is the most accurate model, demonstrating its effectiveness in predicting the fracture behavior of RV-DLSP specimens. Additionally, the VIMC-MEMC-RV-MTS criterion shows commendable accuracy, particularly for the specimens with 30 (deg.) notch opening angle. The scanning electron microscopy (SEM) analysis of the fracture surfaces provides further insights into the fracture mechanisms of RV-DLSP specimens. Notably, distinct fracture patterns are observed based on variations in the notch geometry. Specimens with smaller notch tip radii exhibit fiber cleavage, while those with larger radii display greater fiber interpenetration. These SEM observations are consistent with the fracture load data, which indicates higher fracture loads with increasing the notch opening angle and tip radius. By integrating VIMC and MEMC with the two fracture criteria, accurate predictions of the notch fracture toughness can be achieved, facilitating the design and optimization of 3D-printed PLA components against fracture.

A critical review of composite filaments for fused deposition modeling: Material properties, applications, and future directions

This review paper provides a comprehensive analysis of recent advancements in the development and application of composite filaments for fused deposition modeling (FDM) 3D printing technology. Focusing on the integration of various materials such as nano-fillers, fibers, and bio-based polymers into polylactic acid (PLA) and other thermoplastics, this study delves into how these composites enhance mechanical, thermal and functional properties of the printed objects. We critically assess studies that investigate the impact of raster orientation, filler content, and material composition on tensile, bending, and impact strength, as well as on the thermal stability and degradation behavior of composite filaments. The review highlights key findings from the literature, including the optimization of filament formulations to achieve superior mechanical performance, improved thermal resistance, and specific functional characteristics suitable for a wide range of applications from biomedical to structural components. Moreover, this paper discusses the challenges associated with composite filament production, including material compatibility, dispersion of nano-fillers, and the need for printer hardware adjustments. Future directions for research in the field are identified, emphasizing the potential for new material combinations, sustainability considerations, and the development of filaments designed for specific industrial applications. An effective way to better meet designers’ expectations for qualified materials is composite filaments. This review focuses on how these elements can be applied to improve both product design and functionality. A guide is presented in choosing composite filaments that can meet the features expected from the designed product.

Additively manufactured carbon fiber reinforced-polyamide component: a study based on statistical modeling and regression analysis

This paper presents the experimental assessment of the hardness characteristic of additively manufactured polyamide (PA 6) composite reinforced with carbon micro-fibers. The carbon fiber-reinforced polyamide (CFPA) components were manufactured using the additive manufacturing technique—fused deposition modeling (FDM). The experiments were conducted for testing the hardness of the samples using a Shore-D hardness tester. The novel contributions of the work towards the manufacturing fraternity include selecting a scantly researched material like CFPA, and the elaborative investigation of hardness variation with the alteration of the prime parameters pertaining to FDM. The effect of the print-related parameters, namely, layer height (LH), infill density (ID), and raster orientation (RO) on the hardness of the CFPA component was studied, and the results were analyzed using statistical analysis tool ‘analysis of variance (ANOVA)’. Moreover, a regression model was developed to predict the output response, i.e. hardness for different combinations of the input parameters. Considering an ID of 100% and an RO of 0°, the hardness value of 93.89 at 0.1 mm LH reduced to 88.44 at 0.3 mm LH, depicting a reduction of 5.81%. An increasing trend was observed for hardness with the increase in ID for all the levels of LH and RO. The highest value of hardness (93.89) was achieved at an ID of 100%, with the LH and RO values kept at 0.1 mm and 0°, respectively. The ANOVA suggested that the effect of all three parameters is significant in the study, ID being the most affecting parameter with an effect contribution of 37.88%. The fitness of the adopted model was well justified by the high R-sq value of 0.9618 and significantly low error values in the range of 0.002–0.08.

Enhanced strength, toughness and reliability in crab exoskeleton–inspired 3D-printed porous thermoplastics

PurposeFused deposition modeling enables multiscale structure control. However, most of this structural space is unexplored. Specifically, the impact of biomimetic porous structures on the mechanical behavior and reliability of common thermoplastics are unclear. In this work, porous structures inspired by the multifunctional crab exoskeleton were 3D-printed with different raster orientations, including fully rotating rasters similar to Bouligand structures found in biological materials. Tensile tests and simulations were performed to observe the stochastic behavior of fracture properties and to reveal the underlying origins of mechanical reliability in biomimetic porous systems.Design/methodology/approachTensile tests were performed on 3D-printed porous structures with four different rasters. These rasters were biomimetic Bouligand, semi-Bouligand, 00 raster and 45°/−45° raster. In addition, two different sets were manufactured to observe the impact of contours on the mechanical behavior. A total of 137 tensile tests were performed. A total of 88 finite element simulations were executed using Abaqus built-in Hashin damage initiation criterion and energy-based damage evolution law. Weibull analyses were performed to quantify the stochastic properties.FindingsBiomimetic Bouligand structure is effective in increasing fracture strength. Average fracture strength of the Bouligand structure was 33% higher compared to the default 45°/−45° and 10% higher compared to 00 rasters. Variations in strength were lower in Bouligand structure compared to the default 45°/−45° raster. However, 00 raster had the highest Weibull modulus m = 54 compared to Bouligand m = 25 and 45°/−45° m = 17. Simulations showed that Bouligand structure is effective in increasing the mechanical reliability through local damage accumulation around the holes. The simulated Weibull modulus of the Bouligand structure was 40 compared to the moduli of other rasters that ranged from 18 to 25.Practical implicationsThe mechanical reliability of porous Bouligand structures is higher compared to other rasters, which makes the biomimetic structure a better choice for industrial applications. Contours decrease the strength and strain at failure for 3D-printed porous structures. Bouligand structures with rotating raster orientations increased strength and strain at failure when contours are present in the porous structure.Originality/valueTo the best of the authors’ knowledge, this is the first study showing the effects of biomimetic raster orientations on the mechanical behavior and the effects of contours on the tensile fracture properties of 3D-printed porous acrylonitrile butadiene styrene using tensile tests and fracture simulations. This is the first study applying composite fracture model to anisotropic porous 3D-printed polymers.

Build and raster orientation effects on CFRP onyx/aramid impact absorption

Composite materials fabricated via additive manufacturing are becoming more relevant in ready-for use products used in engineering applications like aerospace structures, propellers, electric vehicles, or sandwich cores. Continuous Fiber Reinforced Polymeric (CFRP) composites are 3D-printed composites with tailor-made properties due to the capability of the printing process to deposit matrix and fiber whenever required. However, CFRP products behave differently and have lower mechanical properties than traditional composites. This study aimed to analyze the impact strength of CFRP specimens with gyroid infill and the effects of two build (flat and on-edge) and two raster (0° and 45°) orientations on impact behavior. The gyroid infill helps to obtain a light-weight structure and it has been used in energy absorption applications showing excellent mechanical behavior in thermoplastic 3D-products. The specimens were manufactured using Onyx as the matrix and aramid fiber as the reinforcement materials. The impact energy absorption of CFRP composites was measured using unnotched Izod impact specimens. The impact tests results were statistically analyzed, revealing that the build orientation directly and significantly affects the impact behavior, resulting in higher impact absorption when flat orientation is used to produce CFRP composites. The impact strength of CFRP composites increased 8 times, and 2 times for flat and on-edge oriented specimens, respectively compared to pure Onyx specimens. The variation in impact energy absorption between raster orientations in both build orientations was not significant, the difference in flat-oriented specimens at 0° and 45° was only 0.2 J, and between on-edge-oriented specimens at 0° and 45° was only 0.089 J. Also, the after impact specimens were analyzed to categorize the different failure modes observed. The after-impact analysis showed poor impregnation between aramid and onyx layers, causing delamination, fiber bridging, and fiber exposure failures. The combination of Aramid, Onyx, and a non-solid infill (gyroid) demonstrated positive results in impact behavior, obtaining high-impact absorption (165 kJ/m2) with no more than 56 % of fiver volume. The impact properties information of CFRP composites made with aramid fibers is still very scarce, joined to the lack of information on the impact properties of CFRP composites with non-solid infill, like gyroids or sinusoidal path infills. The results of this research open the possibility of using non-solid infill in CFR process that can be used to manufacture and test ready-for-use CFRP products in tasks that require high-strength, low-weight structures and impact energy absorption.

Fabrication and development of high temperature resisted bronze composites using 3D printed gate pattern through stir casting route

Fused deposition modeling (Additive manufacturing method) is used for printing the gate pattern by considering Acrylonitrile butadiene styrene (ABS), alumina (Al2O3), and silicon carbide (SiC) as raw material. The three compositions of feedstock filaments are ABS −2% Al2O3 − 0. wt % SiC, ABS −2% Al2O3 − 3. wt % SiC and ABS −2% Al2O3 − 6. wt % SiC, which are produced by using melt flow extruder. The melt flow index of three compositions are determined as 2.413 /10 min, 2.403/10 min and 2.389/10 min which are near to ABS melt flow index of 2.44 / 10 min. The gate pattern is prepared by fusion deposition modeling method by considering parameters such as SiC reinforcement (wt %), raster inclination and infill density and best optimal parameter for producing pattern comprising high tensile strength and high flexural strength using Technique Order Preference Similar to Ideal Solution (TOPSIS). The best set of optimal parameter for printing the gate pattern was found out as ABS −2% Al2O3 −6 wt% SiC, infill density of 50 % and raster inclination 0°. This pattern exhibited average surface roughness of 12.6 µm, tensile strength of 40.5 MPa and flexural strength of 73.1 MPa. The lowest tensile strength of 29.3 MPa was observed for 3 % SiC, 50 % infill density and 30° raster orientation. Using the printed gated pattern via stir casting process, four different compositions of bronze composites are synthesized such as Cu-Sn- 0 wt% B4C, Cu-Sn- 2 wt% B4C, Cu-Sn- 4 wt% B4C and Cu-Sn- 6 wt% B4C. Cu-Sn- 2 wt% B4C composite exhibited maximum hardness, tensile strength and impact strength of 55 HRC, 323 MPa and 279 N/mm2 respectively. The lowest tensile strength, lowest hardness and maximum deviation in dimension of 323 MPa, 38 HRC and 0.144 mm was found out for Cu-Sn-6 wt% B4C. The best optimized pattern: ABS −2% Al2O3 −6 wt% SiC, infill density of 50 % and raster inclination 0° was used as a pattern for producing seven casted cubes (Cu-Sn-2 wt% B4C) which shows average dimension of ± 0.12 mm.

Influence of raster orientation on fracture behavior of Ti6Al4V alloy manufactured by Laser powder bed fusion

This study analyzes the fracture characteristics of Ti6Al4V alloy manufacturedby the Laser Powder Bed Fusion (LPBF) technique, specifically investigating the effect of raster orientation. A modified yield function is presented to determine the decrease in load-carrying ability attributed to shear effects. The damage variable includes both the void volume fraction and shear damage variables, taking into consideration the consequences of void interaction. The research utilizes Finite Element Analysis (FEA) together with calibrated modified GTN fracture parameters derived from Hill’s 48 parameters to accurately predict material behavior. Uniaxial tension tests are carried out on samples in different raster orientations:0°, 45°, and 90°. The Scanning Electron Microscope (SEM) is used to conduct a more thorough examination of the fracture’s characteristics. The specimens with a 90° raster orientation exhibit considerable plastic deformation with deepdimples on the fractured surface, along with irregularly shaped voids. In contrast, the sections with 45° and 0° orientations display smaller dimples and smoother cup and cone features without significant plastic deformation. The results demonstrate that the direction of the raster has a considerable impact on the plastic modulus and fracture properties of the material.

Automated Quantification of Raster Orientation of Fused Filament Fabrication Components Using Ultrasonic Testing

Automated Quantification of Raster Orientation of Fused Filament Fabrication Components Using Ultrasonic Testing

Comparative study on bending behavior and damage analysis of 3D-printed sandwich core designs with bio-inspired reinforcements

In this study, novel sandwich core designs with bio-inspired reinforcements were proposed and their bending behaviors were comparatively examined. The geometrical shapes of alligator osteoderm and chambered nautilus shell were utilized as bio-inspired reinforcements for sandwich core structures. Sandwich core structures were produced through the additive manufacturing method. Experimental tests and finite element analysis were performed to determine the bending performances of the proposed sandwich core structures. The load-carrying capacity, deformation ability, damage-tolerant capability, energy absorption, and damage mechanisms of the proposed sandwich core structures were comparatively investigated through experimental and numerical methods. The orthotropic material model and Hashin’s damage criterion were used in the numerical model of 3D-printed sandwich core structures to consider the effect of the filament raster orientation on the elastic and damage behavior of the sandwich core structures. Compared to the classical honeycomb sandwich core structure, while bio-inspired reinforcements improved the load-carrying capacity and damage-tolerant capability of sandwich core structures, they reduced the energy absorption ability of sandwich core structures due to reducing the vertical deformation ability of sandwich core structures. Bio-inspired reinforcements significantly affected the stress distribution and damage behavior of the sandwich core structures. They reduced von Mises stress level at the outer cell edges of the sandwich core structures and caused reinforcement damage instead of outer cell damage.

Nondestructive quantification of internal raster path for additively manufactured components via ultrasonic testing.

This work investigates the viability of discerning the raster pattern of additively manufactured components using high frequency ultrasonic nondestructive testing. Test coupons were fabricated from poly cyclohexylenedimethylene terephthalate glycol using the fused filament fabrication process, in which layers were deposited at various predetermined raster angles. Each printed part was scanned using spherically focused, high-resolution, ultrasonic transducers of various peak frequencies between 7.5 and 15MHz. From the captured waveform data, images are extracted to observe the raster pattern in a layer-by-layer manner, with the results from the 10MHz element yielding the best performance. An in-house MATLAB script was developed to analyze the transducer signal to investigate C-scan images at various depths throughout the component. From the resulting C-scan images, one can consistently identify the proper raster orientation within 2°-4° in each of the first 10 deposited layers, with the accuracy decreasing as a function of depth into the component. Due to signal attenuation, there is insufficient data at depths beyond the 11th and 12th layer, to properly analyze the present data sets accurately. Validation was performed using X-ray computed tomography scans to demonstrate the accuracy of the ultrasonic inspection method.

Effect of nozzle diameter and raster orientation on tensile and fracture behavior of FDM‐PLA specimens under mixed‐mode I/II loading

AbstractFused deposition modeling (FDM) is a material extrusion technique that works by extruding molten filament on a heated platform. In this method, several manufacturing parameters are engaged which affect the mechanical performance of printed parts. In this study, the effects of nozzle diameter on tensile (under two loading rates) and mixed‐mode I/II fracture behavior of printed specimens were examined. The obtained results revealed that testing speed had a minor effect on basic mechanical properties. For instance, ultimate tensile strengths of tensile specimens printed with 1 mm nozzle diameter were 32.56 and 39.71 MPa for test speeds of 1 and 5 mm/min, respectively. Higher nozzle diameters resulted in higher mechanical properties and fracture resistance (e.g., specimens printed with 45/−45° raster angle with 0.4 and 1 mm nozzle diameters indicated fracture loads of 4520 and 5071 N, respectively). Besides, fracture loads were predicted through the equivalent material concept coupled with J‐integral method.

Enhanced Interlayer Adhesion of 3D Printed Poly(lactide acid) with Ultralow Hyperbranched Poly(ester imide)s

The layer-by-layer process of fused deposition modeling (FDM) is well-known for introducing anisotropy in 3D printed parts due to weak interlayer adhesion. Moreover, the existing physical blend modification methods still face the side effects caused by the heavy use of additives, such as high cost, poor biocompatibility and weakening of primary properties. In this study, hyperbranched polymers poly(ester imide)s (HBPEIs) were blended into the poly(lactic acid) (PLA) matrix to enhance the interlayer adhesion of 3D printed parts. The application effect of HBPEIs in different processing modes was discussed. The effect of different amounts of HBPEIs on the mechanical properties of PLA specimens was investigated. Results showed that by adding just 0.1 wt% HBPEIs, the maximum tensile strength for samples printed with a 90° raster orientation increased from 23.1 MPa to 46.6 MPa while maintaining an isotropic behavior at around 95.9 %. Microstructures, rheological behaviors, and thermal properties of the printed specimens were characterized and compared to understand the underlying enhancement mechanism. It suggested that HBPEIs significantly improved interlayer adhesion by promoting chain diffusion and cold-crystallization between layers. This study showed that using ultralow additives can significantly enhance the interlayer adhesion in FDM parts.

Fatigue response of multiscale extrusion-based additively manufactured acrylonitrile butadiene styrene-graphene nanoplatelets composites

This study investigates the effect of varying concentrations of graphene nanoplatelets (GNPs) on the mechanical and fatigue characteristics of acrylonitrile butadiene styrene (ABS)/GNPs nanocomposites, both in filament form and as 3D-printed parts with different raster orientations. Quasi-static and cyclic loading tests were performed on specimens containing 0.1 wt%, 0.5 wt%, 1.0 wt%, and 2.0 wt% GNPs. The results indicated that the addition of 0.1 wt% GNPs to the ABS polymer matrix increased the ultimate tensile strength (UTS) of the filament by 18 %. Addition of 1.0 wt% and 2.0 wt% GNPs to the matrix improved the Young's modulus of the filament by up to about 35 % but did not enhance the UTS. The filament containing 0.5 wt% GNPs demonstrated the highest fatigue life, even higher than that of the standard samples fabricated through injection molding technique. This was due to its high static strength, Young's modulus, and ductility. However, when the ABS/GNPs nanocomposites were 3D-printed, the addition of GNPs had no major impact on their fatigue life, especially in the higher load levels. Inadequate adhesion and reduced interlayer bonding strength resulted in a detrimental impact on fatigue life of 3D-printed objects. The extrudate-swell phenomenon seems to significantly affect this reduction in fatigue life. To address this, larger nozzle diameter (0.6 mm) was used in fabricating 3D-printed samples. Results indicated that samples with less distortion and smaller extrudate-swell had higher fatigue life. It highlights the importance of considering GNP concentration and printing parameters for optimal fatigue properties in ABS/GNPs composites.

Characterization of shear/tensile mechanical properties of three-dimensional-printed polylactic acid specimens based on orthogonal raster

With the wide application of three dimensional (3D)-printed products, related studies on 3D-printed materials with interleaved raster and subjected to complex stress states should receive sufficient attention. In this study, 3D-printed tensile specimens and two types of shear–tensile specimens with different printed angles were prepared by changing the distribution of internal orthogonal raster orientation. Uniaxial tensile and shear–tensile tests combined with digital image correlation revealed that the ultimate strength and strain of tensile specimens depended on the printing angle, also showed that the maximum values of strength and strain were obtained with the printing angle of 0°/90°. At different printing and slot angles, ultimate strength slightly differed, whereas ultimate strain remarkably differed, between the two kinds of shear–tensile specimens. Subsequently, the corresponding failure mechanism, such as internal raster necking, delamination, and deflection, dependent on printing and slot angles were analyzed by combining the fracture morphologies of the tensile and shear–tensile specimens.

Effect of raster orientation on pure nylon, carbon fibre nylon, and glass fibre nylon using three-dimensional printing

In this study, pure Nylon 6 is taken for investigation and printed in fused deposition modelling, with short carbon fibre, and short glass fibre as reinforcements. The material behaviour under static and dynamic thermal analysis was measured. The specimens were three-dimensional printed as per ASTM standards, and their mechanical behaviour was analysed. According to the findings, a short carbon fibre-printed specimen results in a maximum tensile strength of about 76% and a flexural strength of 89%. Virgin nylon results in the highest impact properties, showing that adding short fibre reduces the impact strength. The dynamic thermal analysis of virgin nylon, short carbon fibre, and short glass fibre results reveals that carbon fibre nylon increases storage modulus, whereas glass fibre nylon increases loss modulus. The nylon reinforced with short carbon fibre results show improved behaviour under static and dynamic thermal conditions.

Parametric analysis of additively manufactured polymer nanocomposites: A experimental and multiscale study

Fused Filament Fabrication (FFF) or Fused Deposition Modeling (FDM) is a widely utilized additive manufacturing technology in a variety of sectors. However, voids, poor bonding between layers, and FDM parameters commonly affect the FDM-printed objects, altering their strength. Carbon nanotube (CNT) composites for FDM printing have been researched by researchers to improve their characteristics. This paper proposes an efficient three-scale computational model for predicting mechanical properties as well as a unique water-quenching process for preparing CNT-infused filaments. The influence of FDM process parameters on mechanical properties is revealed by extensive parametric analysis. When compared to pure ABS, the CNT-infused composite demonstrated better bonding and modulus. The experimental study showed that an increase in the layer height deteriorates the elastic modulus by 21.03 % and 27.92 %, for ABS and ABS-CNT, respectively. The infill density increases the modulus by 49.3 % and 69.6 % for pure ABS, from 100 % to 75 % and 50 %, respectively. For parts printed in 0–00 and 0–900 orientations, a 2.11 % and a 1.7 % decrease were found for pure ABS and nanocomposite, respectively. The computational results were in good agreement with the experimental findings, with the difference varying from 10.15 % to 5.5 % for 0.1 mm and 0.2 mm layer heights. For other parameters like the raster orientation, the difference for 0–00 and 0–900 was 5.3 % and 6.9 %, respectively. The computational results agree with the experimental results, making it a useful tool for optimizing FDM printing and exploiting CNTs to improve part performance.

Nondestructive Evaluation of Nylon/carbon-Fiber Additively Manufactured Components Using Rotational Eddy Current Testing

ABSTRACT This work applies high-frequency rotational Eddy Current Testing (ECT) to characterize various material and manufacturing properties of fiber-filled fused filament fabrication (FFF) components. Using the FFF process, multilayer coupons were produced with varying filament feedstock materials, extrusion multipliers, and raster orientation patterns. With extrusion multiplier being used to adjust interlayer void content, these manufacturing variables were investigated given their significant influence on the mechanical performance of FFF samples. A custom 15 MHz transmit-receive (TR) ECT probe demonstrated sufficient sensitivity to visualize the phenomena of the swept variables. Furthermore, the extraction of simple features from the rotational ECT scans produced clustering and trendlines consistent with observations from X-Ray computed tomography (CT). Thus, this novel approach to nondestructive evaluation (NDE) of fiber filled FFF components is effective for detection and characterization of impactful AM material properties.

A Comparative Investigation of the Reliability of Biodegradable Components Produced through Additive Manufacturing Technology.

Using the linear elastic finite element method, we investigated how defects significantly influence the integrity of 3D-printed parts made from biodegradable material by experimental techniques and numerical simulations. A defective flaw was incorporated into the tensile test dog-bone sample using Computer-Aided Design and processed by slicing software. Three distinct raster angles examine two sets of samples, one featuring intact specimens and the other with the introduced defects. An open-source 3D printer was used to fabricate both sets of samples, utilizing biodegradable PLA material. In finite element analysis, we employed a highly detailed model that precisely accounted for the geometry and dimensions of the extruded 3D-printed filament, accurately replicating the actual configuration of the 3D-printed samples to an extent. Our study involved a thorough comparative analysis between the experimental results and the FEA simulations. Our findings uncovered a consistent trend for the intact and defective samples under tensile load. Specifically, in the intact case, the samples with a zero-degree raster orientation presented the highest resistance to failure and displayed minimal elongation. Remarkably, these conclusions paralleled our observations of the defective samples as well. Finite element analysis revealed that the stresses, including Principal, Max shear, and Von Mises, were remarkably higher at the 3D-printed samples' outer surface than the inner layers, reflecting that the failure starts at the outer surface since they exceeded the theoretical values, indicating a significant discrepancy between the simulated and anticipated values.