bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physical, Mechanical, and Thermal Characterization of Unfilled and Carbon Fiber Filled Polyamide (PA) Filaments and Corresponding Fused Deposition Modelling Fabricated Samples
Authors: Shah Adarsh Kumar , Jain Atul 
Published: August 2024

Abstract
Fused deposition modelling (FDM) represents a promising domain in 3D printing techniques that fabricates objects layer by layer from 3D CAD data. While FDM excels in fabricating pure polymer composite parts, the limitations of matrix polymers necessitate the development of fiber-reinforced polymer composites. Despite polyamide’s superior mechanical properties as a composite matrix, there’s limited research on short carbon fiber-reinforced polyamide (PA) in FDM. Moreover, previous studies typically focus solely on evaluating the tensile properties of FDM printed parts, neglecting feedstock filament properties. Understanding and enhancing the material properties of commercially available carbon fiber polyamide (CF/PA) filament remains a challenge.
This study renders a thorough examination of the microstructural changes and property evaluation pre and post-FDM printing. In this work, raster angles were examined, with a focus on their direct influence on mesostructure, solid-state sintering mechanics, and resulting composite part characteristics through inter-bead and inter-layer bonding, affecting voids, fibers, and the base material matrix. Results show significant fiber breakage, leading to a 31.30% reduction in the average length of fibers from filament to printed parts. While the filament maintains high fiber alignment, printing occasionally leads to misalignment. Tensile tests reveal anisotropic properties in FDM samples with varied raster angles. Short carbon fibers decrease strength but boost Young’s modulus in filament-to-FDM conversion. Examination of fractured surfaces reveals distinct failure modes for filament and printed test coupons. TGA confirms nearly 20 wt.% carbon fiber in the filament, with pure PA filament and samples yielding minimal residue. DSC results indicate enhanced thermal stability with carbon fiber reinforcement, while XRD reveals distinct amorphous behavior in both filament and printed parts.
Finite Element Modeling of Laser Powder Bed Fusion Process Used for Consolidating W-25 Wt.%Re Alloy Pin Tool for Friction Stir Welding
Authors: Alshami Ali , Shuaib Abdelrahman 
Published: August 2024

Abstract
The main challenge to researchers in friction stir welding (FSW) steels and high temperature alloys, using pin tools from refractory metal alloys such as W-25wt.%Re alloys, is to develop the tools that stand the process harsh conditions. Most recently, laser powder sintering to consolidate W-25wt.%Re alloys have shown promising results in producing pin tools for FSW. These results are the motivation for the authors of this paper to consider using a laser powder bed fusion additive manufacturing (LPBF-AM) process for consolidating W-25wt% Re powder alloys, in two steps. First, use finite element modeling to identify the levels of the LPBF-AM process parameters that will produce a pin tool that has the desired mechanical and physical properties for FSW welding steels and high temperature alloys. Second, use the identified process parameters to produce an experimental pin tool and evaluate its suitability for welding steels and high temperature alloys, with respect to tool mechanical and physical properties. The results of the finite element modeling, which are reported in this paper, include effects of the LPBF parameters on the resulting melting pool formation and geometry, as well as on the residual stresses that develop during the laser powder sintering process.
Impact of Heat Input and Step Over Distance on Part Geometry for Multi-Bead WAAM Components
Authors: Hussein Zaky , Goodwin Jesse , McCoy Matthew , Bose-Bandyopadhyay Shohom , Saleeby Kyle , Saldaña Christopher 
Published: August 2024

Abstract
This study investigates the impact of heat input and overlap ratio or stepover distance on part geometry in wire arc additive manufacturing (WAAM). In this work, an experimental approach was taken to quantify the variation in height and aspect ratio of walls at different combinations of overlap and heat input. Multi-bead walls were deposited with the overlap ratio varying from ½, ⅔, and 1 at a low, medium, and high-power set point on the welding power supply. A relationship between heat input, overlap ratio, and the resultant part geometry is established.
Trials with an overlap ratio of one and low to medium heat input exhibited greater lack of fusion defects than the high heat input trials. At higher heat input levels, the as-deposited geometry was found to have less variation in height and an increase in aspect ratio compared to lower heat input trials. The aspect ratio of deposited walls ranged from approximately 1, for the low-power trial with an overlap ratio of ½, to approximately 7, for the high-power trial with an overlap ratio of 1. Additionally, the low and medium power trials with an overlap ratio of ⅔ exhibited the least height variation in the top surface for those heat input levels with an average range of 2.9 mm and 1.8 mm respectively. For the high heat input trials, an overlap ratio of 1 was observed to have the least variation in height with a standard deviation of 0.42 mm and an average range of 1.7 mm; however, lack of fusion defects were present in the top surface and the part cross section.
Brief Paper: Geometric Determinants of Material Jetting-Enabled Bi-Material Interface Integrity Using Polyjet 3D Printing
Authors: Aberdeen Nolan J. , Forghani Kimia , Sochol Ryan D. 
Published: August 2024

Abstract
Among the wide range of additive manufacturing — or “three-dimensional (3D) printing” — technologies, “material jetting” approaches are distinctively suited for multi-material fabrication. Because material jetting strategies, such as “PolyJet 3D printing”, harness inkjets that allow for multiple photopolymer droplets (and sacrificial support materials) to be dispensed in parallel to build 3D objects, distinct materials with unique properties can be readily unified in a single print akin to combining multiple-colored inks using a conventional 2D color printer. Although researchers have leveraged this multi-material capability to achieve, for example, 3D functionally graded and bi-material composite systems, there are cases in which the interface between distinct materials can become a key region of mechanical failure if not designed properly. To elucidate potential design factors that contribute to such failure modes, here we investigate the relationship between the interface design and tensile mechanical failure dynamics for PolyJet-printed bi-material coupons. Experimental results for a select set of bi-material sample designs that were 3D printed using a Stratasys Objet500 Connex3 PolyJet 3D printer and subjected to uniaxial tensile testing using a Tinius Olsen H25K-T benchtop universal testing machine under uniaxial strain revealed that increasing the surface contact area between two distinct materials via changes in geometric design does not necessarily increase the interface strength based on the length scales and loading conditions investigated in the current study and that further studies of the role of multi-material geometric designs in interface integrity are warranted to understand potential mechanisms underlying these results. Given the increasing interest in material jetting — and PolyJet 3D printing in particular — as a pathway to multi-material manufacturing in fields including robotics and fluidic circuitry, this study suggests that multi-material interface geometry should be considered appropriately for future applications.
An Investigation of the Effects of Vibration Compensation on Print Quality of High-Speed Metal Extrusion Based Additive Manufacturing
Authors: Shirzad Sajad , Chou Cheng-Hao , Versin Alexandru , Habbal Osama , Okwudire Chinedum , Pannier Christopher 
Published: August 2024

Abstract
Metal paste extrusion is an emerging metal additive manufacturing process at the intersection of fused filament fabrication and binder jet printing categories. It produces parts using extruded beads of a metal-and-binder paste and achieves final densification in a sintering furnace cycle. In the metal paste extrusion process, reducing build time is crucial for improving process economics. Similar to fused filament fabrication, the toolhead positioning in metal paste extrusion can induce vibrations in the printer frame and components, especially at high acceleration and speed needed to reduce build time. These vibrations can lead to defects in the deposited part.
In this study, a commercially available vibration compensation algorithm, initially developed for fused filament fabrication, is applied to metal paste extrusion for the first time to reduce build time. The algorithm uses the natural frequencies and damping ratios of the machine’s motion system to predict and compensate for vibrations. Three test conditions are employed to produce sample parts in stainless steel 316L for geometric, material, and mechanical property evaluation: nominal printing settings without vibration compensation (print speed 40 mm/s), faster printing settings without vibration compensation (print speed 70 mm/s), and the same fast settings with vibration compensation.
The test part consists of three sections: a solid (∼100% infill) section, a low-infill section (∼40%) where the infill and meshing are visible, and another low-infill section with two top layers. The resulting samples are analyzed for geometric error, density, and hardness effects. Geometrical errors are observed using macro photography, particularly in the outer perimeters at the corners. Voids (gaps between beads) within the top layer are observed using 3D scanning. Density following ASTM B311 standards and subsequently porosity are measured. The final test involves Rockwell B hardness testing at three specified points on the samples.
Without vibration compensation, the outer perimeter exhibits ringing. Faster printing with vibration compensation demonstrates savings in build time without negatively affecting the quantified geometric, material, or mechanical properties.
Data Efficient Modeling for Prediction and Forecasting of WAAM Process Conditions
Authors: Thien Austen , Van Handel Nicole , Hu Helen , Saleeby Kyle , Saldana Christopher 
Published: August 2024

Abstract
Wire arc additive manufacturing (WAAM) utilizes conventional welding processes and wire-feedstock to deposit material layer by layer until a near net-shape geometry has been achieved. This approach gives WAAM great potential among metal additive manufacturing processes for its ability to produce larger scale components much faster than powder-based processes. The selection of certain initial WAAM process parameters, such as input power and interlayer dwell time, can often impact the stability of the contact-tip-to-workpiece distance (CTWD), current, voltage, and linear energy density during deposition. The resulting process stochasticity can cause variations in part geometry, microstructure, and mechanical properties. Therefore, it is desirable to create process models that can predict these WAAM process condition values for a variety of initial process parameter settings. These predictions can then be used to optimize initial WAAM process parameter settings or forecast when process condition instability is expected to occur. In the present work, single-bead multi-layer walls are deposited using a variety of input power and interlayer dwell time settings. Two different modeling approaches are then investigated: multilayer perceptron (MLP) regression and time series forecasting. An artificial neural network (ANN) is trained to predict process condition values based on the initial WAAM process parameters and a given time in the deposition process. Autoregressive integrated moving average (ARIMA) and long-short term memory (LSTM) time series models are trained to forecast subsequent process condition values based solely on the previous process condition values with no prior knowledge of the initial WAAM process parameters. The models are evaluated and compared based on their accuracy in predicting data streams of CTWD, current, voltage, and linear energy density. Additionally, the effect of training data quantity on model accuracy is examined for each model approach. For the ANN model, the training data size is decreased by reducing the resolution of the time series data as a whole and by reducing the number of layers that are used in the training dataset. For the ARIMA and LSTM models, the training data size is limited by reducing the resolution of the time series process data. Additionally, the lag order or “lookback” period, which is a key hyperparameter of both models that represents that number of previous data points needed to forecast a subsequent data point, is optimized via a grid search when the models are trained. Overall, this study will seek to provide modeling techniques to minimize process condition instability by optimizing initial WAAM process parameters and to forecast process condition instability so that it can potentially be mitigated.
Irradiation and Hip Impact on Microstructure and Small-Scale Mechanical Properties of AM Nuclear Reactor Materials
Authors: Nipa Lutfun , Siller Hector R. , Sharma Mohin , Rout Bibhudutta , Mirshams Reza A. 
Published: August 2024

Abstract
The requirement for advanced materials in nuclear reactor applications highlights the necessity for a profound understanding of their behavior under challenging conditions, including radiation exposure. Until nuclear energy remains a significant source of energy production worldwide, 17-4 PH SS holds a crucial role in safeguarding the reliability and efficiency of nuclear reactors. This study delves into the optimization of 17-4 Precipitated Hardened Stainless Steel (17-4 PH SS) through a combination of Additive Manufacturing (AM) and postprocessing techniques. Hot Isostatic Pressing (HIP) is utilized to mitigate flaws such as pores, voids, and microcracks. Simultaneously, irradiation is harnessed to simulate the microstructural and mechanical properties enhancing reliability and efficiency of nuclear reactors. To comprehend the influence of HIP and irradiation techniques to improve the material’s compatibility for high-temperature & high-radiation settings; microstructural characterization in aspects of surface morphology, texture, and fractography is undertaken. Additionally, small-scale mechanical testing using nanoindentation process is used to evaluate the mechanical characteristics for hardness and modulus, offering important insights into the endurance of the material in radiation-intensive conditions. A thorough evaluation of the material’s response to these treatments in the context of nuclear reactor applications is provided by comparing these properties between specimens in different orientations subjected to HIP and irradiation and as-received LPBF-manufactured material. The results indicate that LPBF-fabricated 17-4 PH SS at optimized process parameters in both parallel & perpendicular orientations to the build direction provides distinctive microstructural & mechanical responses, which are notably enhanced by applying HIP treatment and irradiation serving as a hardening mechanism for as-printed samples.
Measuring Overhang Down-Skin Dross Depth and the Inter-Dependency on Melt Pool for Laser Powder Bed Fusion Additive Manufacturing
Authors: Yang Zhuo , Kim Jaehyuk , Lane Brandon , Lu Yan 
Published: August 2024

Abstract
The overhang down-skin surface exhibits distinct behaviors compared to the regular up-skin surface in the powder bed fusion process. Evidence suggests that weak support could be the primary cause of these differences. Previous studies by the authors have indicated that the unique features on the overhang down-skin surface may result from a series of abnormal melting conditions. This paper measures the dross depth of overhang down-skin surface using registered micro-x-ray computed tomography (XCT) data. In addition, it extracts features of the melt pool related to the overhang from overhang 1,000,000 in-situ melt pool images. Four overhang parts with identical geometry and process parameters were fabricated using a powder bed fusion testbed in this study. The results demonstrate that the behavior of the overhang down-skin surface is repeatable across all four parts. The depth of dross is influenced by geometric factors such as the overhang angle and position. The study also reveals that the weak support provided to overhang surface can affect melting in multiple layers, including both the current and future layers. Additionally, this study finds the dross depth and top-surface melt pool size do not have significant statistical correlations. However, a preliminary finding suggests users may identify the extremely large overhang dross formation by monitoring melt pool features in multiple layers above the overhang.
Brief Paper: Understanding the Role of Print Bed Thermal Behavior on Defect Formation in Fused Filament Fabrication
Authors: Keim Anna O. , Young Jaylen A. , Hanson Cyra A. , Collins Megan N. , McClain Monique S. 
Published: August 2024

Abstract
Fused Filament Fabrication (FFF) has become increasingly popular due to its accessibility and rapid fabrication abilities. However, FFF cannot reliably reproduce prints and often suffers from low print quality, which negates many of its benefits. Most previous work in improving FFF has focused on optimizing print parameters, yet results still vary from print to print and printer to printer. Recently, there has been an emphasis on detecting the formation of anomalies using nondestructive methods such as infrared (IR) thermography and other imaging techniques that monitor the part in-situ. While these approaches can identify the formation of geometric anomalies, they are limited to surface and subsurface observations. Furthermore, analyzing images for anomalies is computationally expensive compared to integrated thermocouples that can be used to flag thermal anomalies. This research aims to investigate the unstudied heat transfer interactions between the print bed and cooling fan that impact part quality (e.g., warping, shrinkage, etc.) and local polymer properties (e.g., crystallinity) via thermocouples integrated into the print bed. This is accomplished by printing 1 cm PLA cubes at bed temperatures from 60 to 110°C, and by conducting no-extrusion experiments to measure the bed thermal behavior without printing. It was found that the measured bed temperatures varied spatially across the print bed, and significant interactions between the cooling fan and print bed were measured at the print location. At 100% fan speed, the central thermocouple temperature decreased by 18.53°C and 8.71°C at given bed setpoint temperatures of 110°C and 60°C, respectively. These interactions often led to print failure at high bed temperatures, as excessive cooling near the built-in thermistor caused increasing print bed temperatures at other locations. This cooling is suspected to have triggered a bed thermal runaway error at high temperatures (∼120°C). Lastly, the effect of the cooling fan on print geometry was observed by varying the layer at which the fan turned on. Turning the fan on later in the process led to severe geometric anomalies in the upper layers of the print. Ultimately, this work shows the importance of including the effect of the cooling fan on the print bed in models of the FFF process. Understanding this relationship will allow for the development of fan cooling strategies that will not interfere with printer performance or print quality, leading to consistent fabrication of higher-quality parts.
Numerical Analysis of the Melt Pool Kinetics in Selective Laser Melting Based Additive Manufacturing of Thermoelectric Powders
Authors: Suresh Jagannath , Goyal Gagan K. , Wang Haozheng , Zuo Lei 
Published: August 2024

Abstract
Thermoelectric generators convert heat energy to electricity and can be used for waste heat recovery, enabling sustainable development. Selective Laser Melting (SLM) based additive manufacturing process is a scalable and flexible method that has shown promising results in manufacturing high zT Bi2Te3 material and is possible to be extended to other material classes such as Mg2Si. The physical phenomena of melting and solidification were investigated for SLM-based manufacturing of thermoelectric (Mg2Si) powders through comprehensive numerical models developed in MATLAB. In this study, Computational Fluid Dynamics (CFD)-based techniques were employed to solve conservation equations, enabling a detailed understanding of temperature evolution within the molten pool. This approach was critical for optimizing processing parameters in our investigation, which were also used for printing the Mg2Si powders using SLM. Additionally, a phase field-based model was developed to simulate the directional solidification of the Mg2Si in MATLAB. Microstructural parameters were studied to correlate the effects of processing parameters to the microstructure of Mg2Si.
Sustainability Evaluation of Traditional and Additive Manufacturing for Mold Insert Application
Authors: Zhao Jing , Riggle Zayda , Mendis Gamini , Yang Yiran 
Published: August 2024

Abstract
The exceptional speed and quality achieved through injection molding have made it a great tool for high-volume production. However, the time-consuming process of debugging molds makes it expensive and leads to resource wastage. In response to the fast-growing demand for low-cost and fast production, additive manufacturing (AM) emerges as a promising candidate for cost-effective mold design and fabrication. This innovative approach not only circumvents the high initial investment of tooling associated with traditional injection molding but also offers significant advantages in terms of flexibility in design and manufacturing. Moreover, it provides the potential for creating customized molds on demand, allowing for reduced lead times and enabling rapid production. In this study, a comparative analysis is conducted to evaluate an injection mold insert produced using traditional machining processes and AM. An injection mold insert is designed for pharmaceutical applications and then manufactured using a computer numerical control (CNC) machine tool and two popular AM processes — fused deposition modeling and stereolithography. A combination of three critical AM process parameters (i.e., layer thickness, build angle, and infill rate or post-curing time) is selected and used for fabricating the injection mold inserts; meanwhile, sustainability and quality are evaluated. More specifically, the total energy consumption is quantified and compared for the three manufacturing processes, and the unit manufacturing cost is computed comprising energy cost, labor cost, and materials cost. In addition to sustainability measures, the mechanical strength in terms of hardness of the mold inserts is also investigated as their ability to withstand the high pressures encountered during the injection molding process affects the number of molding cycles before a failure. The dimensional accuracy is also experimentally analyzed to evaluate whether the injection molded products will be manufactured to appropriate tolerances. The results of this study confirmed the feasibility of adopting AM techniques as a viable alternative for injection mold insert manufacturing with lowered unit manufacturing costs and reduced energy consumption. The lower mechanical performance of additive-manufactured mold inserts compared with CNC-machined metal parts suggests a reduced number of molding cycles it can withstand, necessitating further research efforts. Addressing this challenge underscores the need for future studies to enhance the mechanical properties of additive-manufactured molds for expanded applicability of AM techniques in the field of rapid tooling used for mold production. The findings of this work present promising cost and energy-saving possibilities through the adoption of AM techniques, providing broader implications for sustainability and circular economy practices.