bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Situ Observations of Shear Localization and Fracture in Machining
Authors: Yadav Shwetabh , Chawla Harshit , Sagapuram Dinakar 
Published: August 2024

Abstract
Using direct high-speed imaging, we study the transition between different chip formation modes, and the underlying mechanics, in machining of ductile metals. Three distinct chip formation modes — continuous chip, shear-localized chip, and fragmented chip — are effected in a same material system by varying the cutting speed. It is shown using direct observations that shear-localized chip formation is characterized by shear band nucleation at the tool tip and its propagation towards the free surface, which is then followed by plastic slip along the band without fracture. The transition from shear-localized chip to fragmented chip with increasing cutting speed is triggered by crack initiation at the free surface and propagation towards the tool tip. The extent to which crack travels towards the tool determines whether the chip is partially fragmented or fully fragmented (discontinuous). It is shown that shear localization precedes fracture and controls the crack path in fragmented chip formation. Dynamic strain and strain-rate fields underlying the each chip formation mode are quantified through image correlation analysis of high-speed images. Implications for using machining as an experimental tool for fundamental studies of localization and shear fracture in ductile metals are also discussed.
A Task Allocation and Scheduling Framework to Facilitate Efficient Human-Robot Collaboration in High-Mix Assembly Applications
Authors: Kang Jeon Ho , Dhanaraj Neel , Manyar Omey M. , Wadaskar Siddhant , Gupta Satyandra K. 
Published: August 2024

Abstract
Automating assembly operations effectively increase efficiency while decreasing the need for humans to perform ergonomically challenging tasks. However, full automation of these tasks is still a work in progress. Leveraging the complementary strengths of humans and robots offers a solution. Humans can handle tasks requiring dexterity by working in a team, while robots undertake routine, supportive roles. However, contingency situations created by task execution failures occur more frequently in high-mix applications because of the high variability in the types of tasks. Work cells that enable collaboration between humans and robots are not likely to be economically viable unless contingency situations are detected and efficiently managed. In such situations, additional contingency tasks must be executed to recover from the contingency, and productively utilizing human agents can help the work cell quickly recover from contingencies. This paper presents a framework for automatically assigning and scheduling tasks to humans and robots to complete multiple assemblies while managing the computational complexity of generating optimal task plans. Additionally, we present methods to generate recovery task plans that effectively resolve those contingencies automatically. In our case study, we present an approach to graphically determine the number of tasks and products to consider with limited computing time.
Application of Dielectric Barrier Discharge Plasma Jet for Enhanced Wettability of Ti Grade 23 Alloy
Authors: Bhardwaj Aryan , Bayki Shayan , Mujumdar Soham 
Published: August 2024

Abstract
Numerous methods, including chemical etching, ultraviolet radiation, and plasma treatment, are used to functionalize the surface of metallic biomedical implants and enhance osseointegration. Among these techniques, the atmospheric pressure dielectric barrier discharge (DBD) plasma jet stands out as a promising process due to its numerous advantages, including lower operational power requirements, a cost-effective setup, and short processing times. Moreover, the plasma jet demonstrates superior flexibility in treating surfaces of components with complex geometries, such as biomedical implants. This research investigates the surface treatment process utilizing a DBD plasma jet to improve the surface wettability and decontamination of Titanium (Ti) Grade 23 for biomedical applications. An increase in the surface wettability of the plasma-treated Ti substrate is demonstrated by a reduction in the water contact angle (WCA), which is linked to the changes in the surface chemistry. The X-ray photoelectron spectroscopy (XPS) analysis reveals that the interaction of Argon plasma with the Ti surface results in the formation of oxide metallic bonds, such as TiO2 and Ti2O3, while simultaneously removing carbon bonds like CO, TiC, and other organic components. This dual action leads to an increase in surface hydrophilicity and facilitates carbon-based decontamination. Further exploration of the effects of plasma treatment is conducted via a parametric study incorporating key plasma parameters such as plasma power, treatment time, and gas flow rate. While the water contact angle is insensitive to the gas flow rate, it is affected by the plasma power and treatment time. An increase in power from 2.4 W to 6 W reduces the water contact angle, followed by an increase due to a subsequent increase in power from 6 W to 13 W. The area treated by the plasma jet expands with higher plasma power or increased flow rate. The study demonstrates that a DBD Argon plasma jet operating at 2.4 W power and a 4 slm gas flow rate can effectively modify the Ti surface with just 2 s of plasma treatment. However, the optimum wettability in terms of minimum water contact angle is achieved with a 5 s plasma treatment at an input power of 6 W and a flow rate of 8 slm. Due to the formation of a surface oxide layer and the enhanced wettability of the Ti substrate resulting from plasma treatment, it is anticipated that these modifications could enhance the adhesion of Ti implants to living tissues and promote osseointegration.
A Preliminary Investigation of Input Shaping to Reduce the Residual Vibration of a Wafer-Handling Robot
Authors: Lin Yung-Chun , Qian Chen , Awtar Shorya , Okwudire Chinedum E. 
Published: August 2024

Abstract
Frog-leg robots are widely used for wafer-handling in semiconductor manufacturing. A typical frog-leg robot uses a magnetic coupler to achieve contactless transmission of motion between its driving motors, which operate at atmospheric pressure, and its end effector (blade) which operates within a vacuum chamber. However, the magnetic coupler is a low-stiffness transmission element that induces residual vibration during fast motions of the robot. Excessive residual vibration can cause collisions between the fragile wafer carried by the robot and cassette, hence damaging the wafer. While this problem could be solved by slowing down the robot, it comes at the cost of reduced productivity, which is undesirable. Therefore, this paper reports a preliminary investigation into input shaping (a popular vibration compensation technique) as a tool to reduce residual vibration of a frog-leg robot during high-speed motions. Two types of motions of the robot are considered: rotation and extension. A standard input shaper is shown to be very effective for mitigating residual vibration caused by rotational motion but is much less effective for extensional motion. The rationale is that the resonance frequencies of the robot are constant during rotation but they vary significantly during extension, hence reducing the effectiveness of standard input shaping. This necessitates the use of more advanced input shapers that can handle varying resonance frequencies to mitigate residual vibration during extensional motion in future work.
Analysis of Friction Effect on Backward Extrusion of Wire Splicing Couplers
Authors: Letendre Nicholas , Ebrahim Abrar , Darzi Shayan , Ha Jinjin 
Published: August 2024

Abstract
Backward extrusion is a conventional metal forming process which is traditionally employed to produce symmetric, cylindrical, and hollow shaped products. During the backward extrusion process, the billet is initially placed within the die and subsequently compressed to draw the material flow through the gap between punch and die. This method offers several benefits, including increase the material utilization, improved dimensional precision and surface quality, satisfactory mechanical and microstructural properties, and the elimination of the need for additional post-processing operations for net-shaping. The precision and surface quality of the extruded product is highly dependent on the choice of lubrication used in the tooling. In this study, wire splicing couplers are designed and manufactured through the backward extrusion process using commercially pure aluminum cylindrical billets. The backward extrusion process is systematically examined at various punch velocities, each executed with two distinct commercially used lubricants. Surface quality is observed differently in two lubricants, especially one could not prevent severe surface damage along the wall. Vickers hardness evaluation on the cross-section reveals that the hardness is uniform along the wall. The part with the lubricant of lower surface quality shows higher hardness than the other. This indicates that the friction related to lubrication can alter the mechanical properties of formed parts in the backward extrusion. In contrast, the punch velocity has a marginal impact on the surface quality and hardness. The extrusion load-punch stroke curves for different lubrication and punch velocity combinations are compared to optimize extrusion parameters for achieving the desired product quality.
Dynamic Force Measurement Using an Accelerometer: A Proof-of-Concept Study
Authors: Randolph Otto , Shih Chin-Cheng , Tai Bruce 
Published: August 2024

Abstract
Metal cutting is a dynamic process that produces forces with a wide array of frequencies and amplitudes. Typically, dynamometers are used to measure these forces, but they are usually limited to a frequency bandwidth of 3 kHz. This maximum bandwidth is further limited by the natural frequency of the measurement setup and force transmissibility through the structure to the dynamometer. While this is acceptable for most metals, research shows that additively manufactured metals produce high magnitude vibrations at frequencies above those recorded by a dynamometer. The magnitude of the forces produced is unknown. Accelerometers are small enough to be placed near the tool-chip interface, reducing transmissivity losses, and can measure frequencies an order of magnitude higher than that of a dynamometer. The challenge is that the collected acceleration data cannot be directly translated into exogenous force data. This paper attempts to reconstruct the missing dynamic forces using a mass-spring-damper system approximation. For proof of concept, the experiment is conducted on a cantilever beam to represent a toolholder. Exogenous cyclic forces are applied using a small, lightweight electric motor rotating an eccentric mass. This eccentric mass produces a known force thanks to the centripetal mass equation. Furthermore, the forces are separately verified by mounting the motor directly to a dynamometer and measuring the outputted forces across a range of frequencies. Hammer testing is used to determine the cantilever beam system’s order and the constitutive constants for the system’s equations of motion (EOM). Next, the exogenous cyclic forces are applied to the free end of the beam. The cyclic forces are measured using the attached accelerometer. The EOM is used to convert the collected acceleration data into a predicted force. The frequency of the cyclic forces is varied across a wide frequency range, from fifty percent below the system’s natural frequency to fifty percent above the natural frequency, and the predicted and applied forces are compared. The results show a match between the predicted dynamic force and the applied force across the entire frequency range and reveals the limitations of using a dynamometer in the same frequency range. The study also discusses the potential applications of this method on an actual machine tool and the associated challenges and limitations. One potential application of this research is that of measuring the high frequency cutting forces produced by additively manufactured parts. One limitation of this method is that it does not capture static and low frequency forces.
Brief Paper: Spiral Laser Keyhole Welding of Aluminum and Copper: Composition, Microstructure and Properties
Authors: Yan Guanjin , Pour Masoud M. , Rinker Teresa J. , Carlson Blair E. , Tan Wenda 
Published: August 2024

Abstract
Laser keyhole welding of dissimilar metals has been widely used in industrial applications. One critical challenge for this process is the formation of intermetallic compounds (IMCs) that undermine the electrical and mechanical properties of the joints. Compared with the commonly used linear contours, welding with spiral contours can provide larger areas of joining and hence higher allowable loading. This can be particularly useful for certain applications. In this research, laser welding experiments with different spiral contours were performed, and the chemical composition, microstructure, and mechanical properties of the joints were characterized. Three spiral distances were used in the experiments. As the spiral distance was changed from 0.1 mm to 0.3 mm and 0.5 mm, the average Cu concentration in the upper region of the joints was decreased, lower amounts of IMCs were found in the joints, and the joints were capable of sustaining higher mechanical loading.
Real-Time Print Tracking in Metal Additive Manufacturing Using Acoustic Emission Sensors and Vision Transformer Algorithms
Authors: Akhavan Javid , Xu Ke , Vallabh Chaitanya Krishna , Manoochehri Souran 
Published: August 2024

Abstract
Directed Energy Deposition (DED) is an additive manufacturing (AM) method with applications in the aerospace, automotive, and healthcare sectors. In such complex and high-stakes applications, accurate and reliable monitoring is indispensable for assuring fabrication quality. Conventional monitoring systems using mechanical encoders and optical devices have limitations such as wear susceptibility and line-of-sight issues respectively, thereby necessitating alternative monitoring systems. One crucial aspect often overlooked in conventional monitoring systems is the real-time printing process tracking. Achieving high accuracy in tracking is paramount for identifying and mitigating defects in real-time, ultimately leading to improvements in fabrication quality. To address this problem, this research employs acoustic emission sensors for real-time monitoring in Laser DED. These sensors augment existing monitoring methods to improve both reliability and part quality. We developed and tested two machine learning models to study acoustic data correlation with the print process tracking. The first model, based on a Hybrid Convolutional Auto Encoder (HCAE), achieved over 94% accuracy in the print head spatial localization. The second, a Transformer-based model, excelled with a 98.5% accuracy rate and computational efficiency in process tracking. Our findings promise enhanced printing process tracking and pave the way for advanced AI algorithms incorporation into AM quality monitoring. The AI-enabled methods developed can be generalized to other manufacturing applications such as Laser Powder Bed Fusion.
A General Analytical Approach to Predict Machining Process Damping
Authors: Theraroz Jonathan , Tuysuz Oguzhan 
Published: August 2024

Abstract
Machining process productivity is adversely impacted by the unstable chatter vibrations causing poor surface quality, excessive loads, and premature tool and machine failures. Depending on the position of the cutting edge element (CEE) along the vibration wave on the part surface, its flank face and hone radius dynamically indent into the material and cause process damping (PD), which improves the machining stability. This article proposes a generalized analytical PD model by lifting the straight flank face limitation of authors’ previously developed approach and extends it to any clearance face geometries used in machining operations. The proposed model employs the dimensionality reduction method by discretizing the two-dimensional (2D) contact between the CEE and the part surface with series of springs to simulate the contact mechanics between the two. Elasto-plastic material model of the workpiece is used to calculate the contact pressure considering the work material properties, cutting edge geometry, machining and vibration parameters as inputs. The PD force is evaluated by removing the effect of the static indentation from the overall contact force. The equivalent viscous damping coefficient is calculated to linearize the PD force and can be used for accurate machining stability prediction of difficult-to-cut materials. The model has been validated with the experimentally identified and finite elements-based PD coefficients, and a stability lobes diagram in orthogonal machining. Initial results reveal that the newly proposed analytical model can eliminate the empirical values identified from time-consuming machining tests and computationally expensive numerical simulations. Next, the introduced method will be extended to PD in three-dimensional (3D) machining processes such as milling with general tool geometries having varying cutting speeds and geometries along the tool axis.
Robot-Mounted Ultrasonic Micro-Wire Bonding Tool for Structural Electronics And Sensors
Authors: Tofangchi Alireza , Caid Cassidy , Wei Danming , Hsu Keng , Popa Dan O. 
Published: August 2024

Abstract
This research describes the development of a cost-effective ultrasonic wire bonding system, which was later integrated into an industrial robot to enhance welding automation. Initially, the team developed an innovative 3D printed adapter to attach the ultrasonic transducer to the tool tip, along with a 3D Gantry platform for manual wire bonding to determine the optimal process conditions. The study examined the influence of different variables, such as wire type and size, ultrasonic power and duration, and mechanical pressure.
In the follow-up phase, the system was further enhanced by integrating the ultrasonic tool with a robotic arm having six degrees of freedom. A control law was developed using the calculated arm stiffness. Through experimental testing, which varied compression strength and pulse duration, the team attempted to identify effective operating conditions via destructive bond strength analysis.
This integration significantly improved the system’s functionality, allowing for more precise automated wire bonding and better data collection for process control. Practical applications demonstrated include automated wire bonding and cutting on aluminum plates and printed circuit boards with small features, using aluminum and gold wires of various diameters. The system’s ability to cut wires in-process allows continuous bonding at different locations without halting the process. Future objectives include implementing real-time monitoring of bonding failures using data-driven methods.
Effect of Static Laser Beam Shaping on Lateral and Vertical Gap Bridging for Welding of Rectangular Copper Hairpin Windings
Authors: Al Botros Rehab , Pari Maria Teresa , Fortunato Alessandro , Ceglarek Dariusz , Paolini Bryan , Franciosa Pasquale 
Published: August 2024

Abstract
In the race towards net-zero transportation, research in electric motor manufacturing is of significant value. Although rectangular hairpin winding provides higher power density for the stator compared to round wire, critical joining challenges need to be addressed. Motivated by the inevitable hairpin-to-hairpin gaps caused by misalignments and part tolerances, this paper investigates the impact of laser beam shaping on gap bridging for Cu-ETP hairpins during laser welding process. Two welding setups were investigated, core-only laser beam (100% core power, 0% ring power) and ring-dominant laser beam (40% core power, 60% ring power). The solidification behaviour of the molten pool was studied via high-speed camera to elucidate the impact of laser beam shaping on gap bridging and the stability of the keyhole and molten pool. Findings indicated that welding with a ring-dominant laser beam results in a more stable process, reduces fluctuations of the keyhole opening, widens the molten pool, and, ultimately, helps to bridge lateral gaps up to 1 mm (50% of the hairpin thickness) and vertical gaps up to 4 mm (200% of the hairpin thickness). The significance of the results is underpinned by the robustness of the selected ring-dominant laser beam which allows to bridge lateral and vertical gaps without changing welding parameters (i.e., number of laser passes). This eliminates the need for expensive adaptive control systems. The same level of robustness could not be achieved with a core-only laser beam.
An Industry 4.0 Project With Data Integration – From Part Design to Chip Flow and Physics-Based Machine Learning for AlMg5
Authors: Lortz Wolfgang 
Published: August 2024

Abstract
For decades scientists have leveraged computers to solve the complex chip-formation problem — the hope is that one day the computer will be able to solve every technological problem such as modeling of large plastic deformation occurring under friction conditions. Despite the significant number of modeling and simulation studies, there is still limited knowledge about the real nature of the chip formation process. Until today, better agreement with practical results is still being sought-after. Analyzing this situation, some scientists founded the industry 4.0 project to create new opportunities and benefits for industry. In manufacturing, this initiative requires data integration from CAD to CAM with associated Quality Management (QM), and leveraging advanced analytics such as artificial intelligence (AI) with machine learning (ML) to solve complicated problems. In metal cutting, one such complicated problem is modeling of chip formation. Prior to leveraging AI, or rather to create the premise for a physics-based approach, the phenomena occurring during chip formation need better and more realistic modeling. This paper is presenting advances in physics-based modeling of chip formation with particularization for AlMg5. Adequate process mechanics will be developed resulting in modeling of chip-formation and simulation of chip flow. Moreover, it could be shown that the theoretically developed cutting result is in good agreement with the existing experimental result. There is only one disadvantage during production in the machining cell — the generated chip is very long and it is blocking the production process. Further investigation was necessary. A chip breaker was developed as a function of the existing production spectrum with individual geometry and kinematics. For different cutting conditions and tool geometry considerations for a physics-based machine learning process are proposed.
Brief Paper: Numerical Validation of Fin Cutting As Mechanical Test Under Extreme Thermomechanical Conditions
Authors: Lopez-Hawa Homar , Moscoso-Kingsley Wilfredo , Madhavan Viswanathan 
Published: August 2024

Abstract
A novel mechanical test capable of measuring the flow stress within an adiabatic shear band is described. The test is validated numerically via high resolution finite element analysis. It is shown that a controllable, planar shear zone may be produced by the test, where the effective strain may be as high as 10, the effective strain rate as high as 106 /s, and the temperature as high as near melting. The test can be used for development of constitutive models that may be utilized as inputs for the modeling of severe deformation processes, including machining.