bluuebunny/crossref_metadata_2025_split huggingface dataset:
Machining of Through Holes in Non-Conductive Aluminum Nitride Ceramic Using Electrical Discharge Machining Process
Authors: Rashid Asif , Jahan Muhammad P. , Perveen Asma , Ma Jianfeng 
Published: January 2021

Abstract
Ceramic materials are known for their high hardness and strength-to-weight ratio, resistance to wear, and chemical inertness. These materials can be deployed at elevated temperature even to the limit where super alloys cannot be used. The distinctive properties of ceramics make them difficult to machine by conventional processes because of their brittleness. Electrical discharge machining (EDM) is a non-contact machining process that can machine any workpiece irrespective of its hardness, as long as the material is electrically conductive. Therefore, the challenge that comes with the EDM of ceramics is the electrical non-conductivity. In this study, an innovative method (modified assisted-electrode method) has been proposed, which can be used to successfully machine through holes in pure and non-conductive ceramic materials using the EDM process. The effect of machining parameters and conductive coating has been studied. In addition, the possible material removal method has been investigated using the scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis. It is found that multi-layer coating with conductive copper tape sandwiched with graphene and carbon nanotubes in between the tape worked as a successful assistive electrode method. The SEM and EDS analysis indicates melting and thermal spalling as possible material removal mechanisms during EDM of electrically non-conductive Aluminum nitride (AlN) ceramics. The deposition of carbon at the edge of the holes indicate generation of conductive carbon layer favoring continuous sparking during the machining process, and this makes the EDM of non-conductive AlN possible. The walls of the drilled holes become conductive and allow the machining to go through even beyond the conductive layer range. The performance characteristics depends on both the electrical parameters and assistive electrode method.
Characteristics of Diamond Abrasive Used in Magnetic Abrasive Finishing of Nickel-Based Superalloys
Authors: Ratay Jason , Yamaguchi Hitomi 
Published: January 2021

Abstract
Nickel-based superalloys have a wide range of high-temperature applications, such as turbine blades. The complex geometries of these applications and the specific properties of the materials raise difficulties in the surface finishing. Magnetic abrasive finishing (MAF) has proven effective in finishing the complex geometries. In MAF, the magnetic properties of the workpiece, tool, and abrasive play important roles in controlling finishing characteristics. This paper presents the effects of nickel coating on the abrasive behavior during finishing and resulting finishing characteristics of Ni-based superalloys. The Ni-coated diamond abrasive is more attracted to the magnet than the Ni-based superalloy surface. As a result, fewer Ni-coated diamond abrasive particles, which are stuck between the magnetic-particle brush and the target surface, participate in surface finishing. Because of this, coupled with the reduced sharpness of abrasive cutting edges due to the coating, Ni-coated diamond abrasive cannot effectively smooth the target surface in MAF. However, the Ni coating is worn off during finishing of the hard, rough, additively manufactured surface. Then, the diamond abrasive participates in finishing as uncoated diamond abrasive and facilitates the material removal, finishing the target surface.
High Precision Tracking of Roll-to-Roll Manufacturing Processes
Authors: Chen Zhiyi , Jiang Baoyang , Ni Jun 
Published: January 2021

Abstract
Methods for controlling tension and velocity in Roll-to-Roll (R2R) processes have been widely studied in literature. Such methods are very effective under normal operating conditions, but the performance will degrade when control efforts saturate the physical capability of systems. This paper presents a constrained linear-quadratic model predictive control (LQ-MPC) scheme for the purpose of reference tracking. Firstly, a discrete-time linearized model for a R2R process is derived based on the governing equations from prior studies. The model is augmented by integrating an incremental behavior into it. Then a model predictive controller is specifically designed to reach zero-offset tracking of tension and velocity references, while the encountered process constraints are enforced at the same time. The constrained control problem is reduced into a quadratic programming problem and solved by using gradient projection method. It is proved that the proposed controller can guarantee local closed-loop stability where process constraints are inactive. Simulation of a five-roller R2R system is conducted to compare the performance of a proposed controller and a typical decentralized PI controller. Results show that the proposed controller achieves better performance in terms of quick response to changing of set points and capability of decoupling the subsystems. It also demonstrates good robustness when reasonable parametric uncertainties are introduced in the system.
Multi-Functional 3D Curvilinear Self-Folding of Glassy Polymers
Authors: Lee Jae Gyeong , Won Sukyoung , Park Jeong Eun , Wie Jeong Jae 
Published: January 2021

Abstract
The selective light absorption of pre-stretched thermoplastic polymeric films enables wireless photothermal shape morphing from two-dimensional Euclidean geometry of films to three-dimensional (3D) curvilinear architectures. For a facile origami-inspired programming of 3D folding, black inks are printed on glassy polymers that are used as hinges to generate light-absorption patterns. However, the deformation of unpatterned areas and/or stress convolution of patterned areas hinder the creation of accurate curvilinear structures. In addition, black inks remain in the film, prohibiting the construction of transparent 3D architectures.
In this study, we demonstrate the facile preparation of transparent 3D curvilinear structures with the selection of the curvature sign and chirality via the selective light absorption of detachable tapes. The sequential removal of adhesive patterns allowed sequential folding and the control of strain responsivity in a single transparent architecture. The introduction of multiple heterogeneous non-responsive materials increased the complexity of strain engineering and functionality. External stimuli responsive kirigami-based bridge triggered the multi-material frame to build the Gaussian curvature. Conductive material casted on the film in a pattern retained the conductivity, despite local deformation. This type of tape patterning system, adopting various materials, can achieve multifunction including transparency and conductivity.
Computer-Aided Design and Additive Manufacturing of Custom Silicone Prosthetic Finger
Authors: Chen Lei , Plott Jeffery , Hildner Matthew , Mei Lillian , Shih Albert , Wensman Jeffery , Kelly Brian 
Published: January 2021

Abstract
Finger and partial finger amputations are one of the most frequently encountered forms of partial hand loss. Most of these amputees can benefit from prosthetic fingers, which should be both functional and aesthetic, to enhance rehabilitation by permitting a more normal professional and social life. Custom prosthetic fingers perform better than off-the-shelf ones due to better fit, comfort, and match to the patients’ physical characteristics. The conventional fabrication process for custom prosthetic fingers uses multiple impressions and molds combined with silicone injection molding to create the final shape. This process has not seen significant changes for decades and comes with a high cost and long wait time, stopping the prosthesis from benefitting the patient in a cost-effective, timely, and lifelike functional way. This study developed a new manufacturing approach for custom prosthetic fingers based on an additive manufactured custom thin-wall mold. The approach was based on optical 3D scanning of the amputees’ fingers and computer-aided design of custom finger prosthetic geometry and the corresponding thin-wall mold. Preliminary clinical study on an amputee patient shows the feasibility of this new custom molding approach and future work will clinically evaluate the performance of the prosthetic fingers created via the computer-aided design and additive manufacturing approach.
Mechanism of Debris Ejection in Atomized Dielectric-Based Electrical Discharge Machining
Authors: Tanveer Asif , Kapoor S. G. 
Published: January 2021

Abstract
Atomized dielectric-based electrical discharge machining (EDM) is a novel machining process in which a thin film of moving fluid resulting from a spray acts as the dielectric in the interelectrode gap. In addition to acting as the dielectric, the thin film also helps to flush the debris away from EDM crater features and requires very small quantity of fluid in doing so. This results in significantly less dielectric consumption compared to the conventional EDM while yielding higher material removal rates and better debris flushing. This paper presents a model-based investigation of the mechanism of debris flushing in atomized dielectric-based EDM. A material removal model is used to predict the amount of debris removed in terms of number of particles ejected during a single EDM discharge. The dielectric material properties and atomization spray parameters are varied in order to produce different ejection conditions and crater geometries, respectively. Particles are ejected from the bottom of crater geometries. The model captures the asymmetry in particle motion caused by the dielectric film flow and predicts the percentage of debris flushed away from the crater center. It is also observed that crater shape and size of debris particles play a role in the amount of debris flushed away.
Fabrication of Electrically Conductive Patterns on ABS Polymer Using Low-Pressure Cold Spray and Electroless Plating
Authors: Akin Semih , Jun Martin Byung-Guk , Tsai Jung-Ting , Park MinSoo , Jeong Young Hun 
Published: January 2021

Abstract
Previous studies have shown that metallic coatings can be successfully cold sprayed onto several polymer substrates. The electrical performance of the cold-sprayed polymers, however, is not generally sufficient enough to utilize them as an electronic device. In this paper, an environment-friendly metallization technique has been proposed to fabricate conductive metal patterns onto polymer substrates combining cold spray deposition and electroless plating to address that challenge. Copper feedstock powder was cold sprayed onto the surface of the acrylonitrile-butadiene-styrene (ABS) parts. The as-cold sprayed powders then served as the activating agent for selective electroless copper plating (ECP) to modify the surface of the polymers to be electrically conductive. A series of characterizations are conducted to investigate the morphology, analyze the surface chemistry, and evaluate the electrical performance and adhesion performance of the fabricated coatings. After 6 hours of ECP, the sheet resistance and resistivity of copper patterns on the ABS parts were measured as 2.854 mΩ/sq and 6.699 × 10−7 Ωm respectively. Moreover, simple electrical circuits were demonstrated for the metallized ABS parts through the described method. The results show that low-pressure cold spray (LPCS) and ECP processes could be combined to fabricate electrically conductive patterns on ABS polymer surfaces in an environmental-friendly way.
Modeling of Dry-EDM Plasma Discharge
Authors: Mujumdar Soham 
Published: January 2021

Abstract
There is a growing interest in developing the dry EDM process as a sustainable alternative to the conventional liquid dielectric-based EDM process. It is shown that the dry EDM process possesses advantages over the conventional process in terms of thermal damage, recast layer, and tool wear. However, there is a need to increase the productivity of the dry EDM process for its successful adaptation in the industry. This paper presents a model of dry EDM plasma discharge with air as the dielectric medium. The model uses global modeling (‘0D’) approach in which equations of mass balance, energy balance, and plasma expansion are solved simultaneously to obtain a time-dependent description of the plasma in terms of its composition, temperature, diameter, and heat flux to electrodes. The model includes reaction kinetics involving 622 reactions and 55 species to determine the air plasma composition. A single discharge dry EDM operation is successfully simulated using the model, and the effect of discharge current on the plasma is studied. An increase in the discharge current increases the electron density, temperature, and diameter of the plasma linearly, while heat flux to the workpiece increases exponentially. Overall, the model provides an essential tool to study the dry EDM process mechanisms at a fundamental level and devise methods for process improvements.
Polymeric Reaction Molding of Biocompatible Materials: Lessons Learned
Authors: Kosnik Sabrina , Piovesan Davide 
Published: January 2021

Abstract
Polymeric materials are often used as structural binders for biomedical applications. The mechanical properties of the material strongly depend on the fabrication process. To this end, we illustrate a set of casting methods for the production of samples to be tested via destructive methods. The curing process of the artifact was controlled during fabrication, and the molds were also made of polymeric materials. The fabrication of molds is illustrated where particular emphasis is posed on the manufacturing and testing of silicone molds using off-the-shelf material.
Cyanoacrylate (CA), Epoxy resin (EP) and Methacrylate ester monomers (MEMs) artifacts have been fabricated using said molds. Of the aforementioned resins, MEMs are a class of thermosetting biocompatible polymers in which fabrication is especially problematic because of the very narrow temperature window at which the monomers polymerize. This research analyzes the casting process of curable materials highlighting the setbacks of using plastic-based molds. Among the cast based manufacturing techniques, specific focus was given to the case where MEMs is made to polymerize in a silicone mold controlling the temperature of the environment. The thermal properties that the silicone-based molds require for the appropriate curing of the polymer are analyzed. It was found that due to the very high heat capacity of silicone, the regulation of the temperature within the mold is difficult often exciding the boiling point of the casted resin.
Study of Effect of Repetition Rate on Laser Shock Peening Using Finite Element Modeling
Authors: Kosaraju Sai , Zhao Xin 
Published: January 2021

Abstract
A two-dimensional finite element model is developed to simulate the interaction between metal samples and laser-induced shock waves. Multiple laser impacts are applied at each location to increase plastically affected depth and compressive stress. The in-depth and surface residual stress profiles are analyzed at various repetition rates and spot sizes. It is found that the residual stress is not sensitive to repetition rate until it reaches a very high level. At extremely high repetition rate (100 MHz), the delay between two shock waves is even shorter than their duration, and there will be shock wave superposition. It is revealed that the interaction of metal with shock wave is significantly different, leading to a different residual stress profile. Stronger residual stress with deeper distribution will be obtained comparing with lower repetition rate cases. The effect of repetition rate at different spot sizes is also studied. It is found that with larger laser spot, the peak compressive residual stress decreases but the distribution is deeper at extremely high repetition rates.
A Micro Arc Oxidation Composite Coating Developed on a Biocompatible Magnesium Alloy for Bone Implant Applications
Authors: Ibrahim Hamdy 
Published: January 2021

Abstract
The biocompatibility, mechanical properties and biodegradable nature of Mg alloys have made them attractive for biomedical applications, especially as bone implants. However, one of the main problems that limit the use of Mg alloy for several biomedical applications is their fast corrosion rates inside the body. Coating Mg-based implants is one of the most extensively studied approaches to address the fast corrosion rates of Mg alloys in the physiological environment. Micro arc oxidation (MAO) coating process has shown very promising results towards reducing the corrosion rates of Mg alloys due to the formation of a protective dense, well-adhered and wear-resistant oxide layer on the surface of the Mg alloy. In this study, the feasibility of coating an Mg-Zn-Ca-based alloy with a composite coating made using a micro-arc oxidation coating process and an immersion (dipping process) was investigated. The corrosion properties and surface characteristics of the coated alloy samples are assessed. The created protective composite coating is used to slow the corrosion rates of an Mg-Zn-Ca-based alloy. The developed composite coating resulted in a significant reduction in the corrosion rates. The results of this study show that it is possible to achieve more controlled corrosion rates of Mg-based implants towards patient-specific bone implant applications.
Incorporating Tool Contact Considerations in Tool-Path Planning for Robotic Operations
Authors: Bhatt Prahar M. , Gong Cheng , Kabir Ariyan M. , Malhan Rishi K. , Shah Brual C. , Gupta Satyandra K. 
Published: January 2021

Abstract
Tool-Path planning is the foundation for automating many manufacturing processes. Robotic manipulators are increasingly being considered to automate tasks that require complex tool motions. Robotic manipulators provide extra degrees of freedom and are more flexible than traditional automation technologies. However, a tool-path needs to be planned and given to the manipulator trajectory generator as input. The traditional tool-path planning considers the tool to have one contact point, known as the Tool Center Point (TCP). This underutilizes the available flexibility of the manipulator. To make use of the manipulator’s flexibility, multiple contact points or multiple TCPs can be considered. These tool contact considerations make the tool path planning problem complex and computationally challenging. In this paper, we present a novel tool path planning algorithm. Our algorithm incorporates the multiple tool contact points consideration during tool-path planning in an efficient manner to generate a high-quality tool-path in a reasonable amount of run time. We evaluated our algorithm on four different test cases. The test cases include the parts with complex geometry and tools which can have surface area for establishing contacts with the part. In these test cases, a traditional single contact tool-path will not work due to geometric constraints, and multiple tool contacts make the problem challenging. Our algorithm was able to generate tool-paths for these four test cases successfully.
Experimental and Simulation Study of Incremental Forming for Titanium Grade 2 Sheet
Authors: Mahajan Peeyush , Pal Mainak , Kumar Rakesh , Agrawal Anupam 
Published: January 2021

Abstract
Incremental sheet forming (ISF) process has gained massive popularity due to its die-less nature. The process shows greater flexibility in making customized sheet metal parts economically and more effectively as compared to the traditional forming processes. This paper mainly focuses on investigating the behavior of commercially pure (CP) titanium grade 2 sheet. Single point incremental forming process has been used to deform the sheet. Workpiece geometry has been chosen as conical rectangular shape, using the unidirectional spiral tool path profile. The deformation of the titanium sheet has been performed with and without the use of lubricating fluid. The finite element analysis (FEA) for the von Mises stress and sheet thickness variation has been carried out on ABAQUS® simulation software. Also, the stretching of the deformed sheet has been examined along the side wall and corner of the deformed surface. The ISF has limitation with respect to the geometrical accuracy and surface finish quality of the formed part. To study the surface quality of the deformed surface, scanning electron microscopy (SEM) has been utilized. Stress triaxiality is another important parameter to investigate the crack initiation and fracture during forming, it has been predicted using Finite element analysis.
Experimental and Numerical Investigation on Micro Friction Stir Welding of Dissimilar Metal Joints
Authors: Kishore Hreetabh , Banerjee Mainak , Rai Saruabh , Kumar Rakesh , Agrawal Anupam 
Published: January 2021

Abstract
Micro Friction Stir welding (μFSW) has found its broader application in the area of packaging of MEMS devices, biomedical components, and joining of micro-mechanical assemblies. This study focuses on the effect of process parameters over the joint strength while joining Al6061-T6 and pure copper sheets of 0.3 mm thickness. Also, a coupled Eulerian-Lagrangian (CEL) numerical model has been developed in the finite element suite of ABAQUS®. The boundary conditions used in the numerical simulation are kept almost similar to the experimental conditions to record thermal results. Moreover, an analytical approach for finding microhardness of welded joints using the Hall-Petch equation is also presented. The process parameters like rotational tool speed and welding traverse speed were found to be dominating in order to get better joint strength. The essential μFSW process parameters combination suggested that 1100rpm rotational speed, 20mm/min. traverse speed and 0.15mm pin depth (tool) result in superior flexural, thermal, and morphological properties of the joint. A good agreement between the experimental and simulation results was found with a maximum of 8% error in the predicted temperature values. The anticipated joint strength and surface characterization of the samples revealed a complex flow and homogeneous mixture at the pin-sheet interaction zone with higher micro-hardness values.
Experimental Analysis of Material Squeeze Factor in Two-Point Incremental Forming of AL 7075-O
Authors: Bansal Ankush , Cheng Randy , Banu Mihaela , Taub Alan , Ni Jun 
Published: January 2021

Abstract
In recent years, incremental sheet forming (ISF) has shown significant potential for economically fabricating sheet metal products required in low volume. Despite its advantages of reduced forming forces and higher material formability, manufacturing complex shapes with acceptable geometric accuracy is still a challenging task. Two-point ISF (TPIF) is one variant that uses a support die to a fabricate part with intricate features. In this study, effects of material squeeze factor in the TPIF process is investigated on part accuracy and formability. Material squeeze factor is defined as the amount of sheet thickness squeezed between the forming tool and support die. It is integrated as one of the processing parameters for generating a pre-defined toolpath of the forming process. However, the effective material squeeze (SFe) obtained in experiments is either zero or significantly lower than the squeeze factor programmed (SFp) in the toolpath due to machine and tool compliance. SFp values are heuristically chosen in literature studies to maintain steady contact between the sheet and die surfaces and avoid forming through degenerated SPIF rather than the “true” TPIF process. For a 67° cone, the part kept losing contact with the die surface below SFp = 30% whereas uniform contact between sheet and die surface is achieved for SFp = 40%. Also, the geometric deviation is significantly reduced from 0.61 mm to 0.39 mm along the wall region with the higher squeeze factor. Similar results are obtained for a benchmark heart shape part.