bluuebunny/crossref_metadata_2025_split huggingface dataset:
Out-of-Autoclave Repair of Composite Laminates by Using Shape Memory Polymer Foams
Authors: Bellisario D. , Quadrini F. , Santo L. , Iorio L. , Gallo N. , Corvaglia S. 
Published: November 2019

Abstract
Composite repairing is an issue because of the size of the parts, the cost of the production equipment and the poor consolidation between the parent part and the repairing patches. In this study an out-of-autoclave procedure is proposed where the agglomeration pressure is provided by shape memory foams. These foams can be shaped in the desired form by means of a thermos-mechanical cycle, and provide additional pressure if constrained during recovery. Shape recovery is achieved by using the same thermal cycle which is necessary for the cure of the patches. In this study, thermoplastic shape memory foams have been characterized to evaluate the agglomeration pressure they can provide as a function of the compression strain. In order to show the feasibility of their application, the cure of a composite laminate has been performed by using pre-shaped shape memory foams. Results show that a good consolidation is achieved despite of the absence of a vacuum bag.
Conformal Circuit Fabrication via Flash Light Sintering and Forming
Authors: Devaraj Harish , Malhotra Rajiv 
Published: November 2019

Abstract
This paper investigates sequential Thermoforming and Flash Light Sintering (FLS) of conductive silver nanowire interconnects printed on planar polymer sheets. The resulting interconnect-polymer assemblies are pre-shaped to a desired 3D geometry and can be robustly attached to the surface. This approach avoids interconnect delamination in manual conformation of planar flexible electronics, eliminates heating of the 3D object in direct conformal printing, and enables easy circuit replacement. The effect of the forming strain and FLS fluence on the resistance of the interconnect are studied. The interconnect resistance increases after thermoforming but is reduced significantly by subsequent FLS. The resistance depends nonlinearly on the forming strain, interconnect thickness, and FLS fluence. With the optimal parameters found here this process achieves interconnect resistance of &lt; 10 Ω/cm within 90.8 seconds at 100% maximum strain over a 1 square-inch forming area. The application of this process for complex surfaces is demonstrated via a simple conformal LED-lighting circuit.
Laser Direct Energy Deposition Welding of AISI 316 Stainless Steel Sheets
Authors: Ascari Alessandro , Fortunato Alessandro , Liverani Erica , Lutey Adrian H. A. 
Published: November 2019

Abstract
The present paper assesses the applicability of laser powder direct energy deposition for welding of thin stainless steel sheets. Considering the rapid development of laser cladding and relatively wide range of equipment available in modern industrial settings, this technology can also be applied to laser welding, where the procedure is performed with a filler material comprising blown powder. To this end, an exhaustive experimental campaign has been carried out with the aim of evaluating the influence of the main process parameters, including laser power and powder feed rate, on the resulting weld bead characteristics. Two joint configurations have also been considered to assess the best solution in terms of both chamfer shape and sheet positioning. Butt and lap joints were prepared, with 30° and 45° V-groove configurations tested and characterized in the former case. In order to assess the resulting weld quality, metallographic analyses were carried out to measure the main morphological parameters of the weld beads, including width, penetration depth and reinforcement, and to evaluate the possible presence of defects such as pores, cracks or lack of melting. Tensile tests were also carried out with the purpose of characterizing the overall mechanical performance of the joints. These tests demonstrated good overall process feasibility and highlighted the fact that lap joints and 30° V-groove butt joints were the best configurations in terms of both weld bead quality and fused zone morphology.
Singular Vector-Inspired Dictionary Learning for Sparse Decomposition of Vibration Signal
Authors: Ding Baoqing , Yan Ruqiang , Wang Shibin , Tong Chaowei , Chen Xuefeng 
Published: November 2019

Abstract
Dictionary design is a primary challenge for sparsity-assisted fault diagnosis techniques. The dictionary can either be specified through signal priors or learned from data samples. In this paper, we propose a singular vector-inspired dictionary learning (SVDL) method, combining signal priors and data samples for sparse decomposition of machinery vibration signal. The SVDL is a data driven scheme for learning dictionary atoms and simultaneously exploring the prior information. It is achieved by alternating between atom design and dictionary update steps. First, we introduce the singular vector as vibration signal priors to atom design procedure. Through singular value decomposition on the Hankel matrix of the vibration signal, the inherent signal features corresponding to mechanical fault can be expressed with some singular vectors. These vectors, closely related to fault features, are extracted as basis vectors to constitute atoms. Second, the vector quantization method is used for atom design, by clustering the extracted basis vectors for the purpose of learning representative atoms. As to the dictionary update step, a strategy including sparse coding and dictionary optimization is adopted to simplify and update atoms. The results of the numerical simulation and experimental application show that the proposed SVDL method outperforms the classical K-SVD method for vibration signal denoising and fault feature extraction.
Exploring the Multi-Stage Effects of Material Preparation and Printing on 3D Printing Product Quality
Authors: Hajifar Sahand , Purnanandam Ramanarayanan , Sun Hongyue , Zhou Chi 
Published: November 2019

Abstract
3D printing is a promising technique to fabricate flexible parts and reduce the supply chain. Various materials, such as metal powders, plastics, ultraviolet (UV) sensitive resins, can be fabricated from 3D printing and form the final printed part. Currently, most researchers either focus on exploring printable materials with good property or focus on the process quality control given a certain type of material. However, for many 3D printing processes, the printing process and product properties are dependent on both the material properties and process settings. To the best of the authors’ knowledge, the quantitative analysis of the interactions of material properties and printing process settings are rarely studied. In this paper, we treat the material preparation and 3D printing as different manufacturing stages, and we explore the multi-stage effects in 3D printing. In particular, we add carbon fiber to the CLEAR resin to alter the material properties for a stereolithography (SLA) 3D printing process. It is observed that the part properties are jointly affected by material properties and printing process settings. Therefore, the material property and process settings should be jointly considered for optimizing 3D printing processes.
Sensitivity Analysis Between Error Motions and Machined Shape Errors in Five-Axis Machining Centers: In Case of S-Shaped Machining Test by a Square End Mill
Authors: Li Zongze , Sato Ryuta , Shirase Keiichi , Ihara Yukitoshi 
Published: November 2019

Abstract
Five-axis machining center, combined three linear and two rotary axes, has been increasingly used in complex surface machining. However, as the two additional axes, the machined surface under table coordinate system is usually different from the tool motion under machine coordinate system, and as a result, it is very tough to predict the machined shape errors caused by each axes error motions. This research presents a new kind of sensitivity analysis method, to find the relationship between error motions of each axis and geometric errors of machined shape directly. In this research, the S-shaped machining test is taken as a sample to explain how the sensitivity analysis makes sense. The results show that the presented sensitivity analysis can investigate how the error motions affect the S-shaped machining accuracy and predicted the influence of error motions on certain positions, such as the reversal errors of the axes around motion reversal points. It can be proved that the presented method can help the five-axis machining center users to predict the machining errors on the designed surface of each axes error motions.
The Quality of Slicing Technologies for Digital Light Processing 3D Printing
Authors: Kwok Tsz-Ho 
Published: November 2019

Abstract
The process planning of a manufacturing method is the key to ensure the quality of the fabricated part. In Additive Manufacturing (AM), slicing is a crucial step in process planning to convert a Computer-Aided Design (CAD) model to a machine-specific format. If the slicing results were incorrect, the manufacturing quality would have no way to be assured. Therefore, it is important to understand the performance of different slicing technologies for AM. Digital Light Processing (DLP) printing is an important AM process that has a good surface finish, high accuracy and fabrication speed, and is widely applied in many dental and engineering industries. However, while most other AM processes are toolpath-based, as a process that uses images as the fabrication tool, the DLP printing has its process planning understudied. Therefore, the main goal of this paper is to study, compare and benchmark the slicing technologies for DLP printing. Three slicing technologies are compared: contour, voxelization, and ray-tracing. They are tested with some common defects in slicing, and their usage in computational resources is also reported. The summary and suggestion are given at the end.
The Realities of Friction in Metal Plastic Flow With Corresponding Results During Metal Cutting
Authors: Lortz Wolfgang , Pavel Radu 
Published: November 2019

Abstract
Metal cutting is a dynamic process with two types of friction: on the one hand, external friction between two different bodies, and on the other hand, an internal friction inside the same material, due to plastic flow. These two different types of friction lead to different chip formation processes. In the case of built-up-edge (BUE), low velocity creates low energy, resulting in a self-hardening effect with BUE. With increasing velocity, the energy will increase and will result in high temperatures with a built-up-layer (BUL). Furthermore, under special circumstances, friction will lead to a self-blockade (a self-blocking state). This situation describes the third stage in metal plastic flow — the creation of a segmental chip. In this case the internal friction takes over.
One question arises: “How can we determine these two types of different friction?” For solving these phenomena new fundamental equations based on mathematics, physics and material behavior have to be developed. This paper presents newly developed equations, which deliver the theoretical distribution of yield shear stress as well as strain rate with corresponding grid deformation pattern in metal plastic flow. For an actual cut, the plastic deformation pattern remains when the process is stopped, and therefore the theoretical result can be compared with cross-sections of the relevant chip formation areas — contrary to outputs such as stress, strain rate and temperatures which are all functions of position and time.
All this will be shown and discussed in the paper, and stands in good agreement with experimental results.
A Hybrid Approach for Heterogeneous High-Density Data for Surface Topology Classification: A Case Study
Authors: Dastoorian Romina , Wells Lee , Tian Wenmeng 
Published: November 2019

Abstract
Recent measurement system developments have brought new opportunities to enhance the performance of quality control (QC) systems in manufacturing. Digital cameras and 3D optical scanners are among the advanced measurement systems that can represent an entire product’s surface. These data-rich environments have been widely used in automated surface defect detection. However, despite the fact that datasets from both digital cameras and 3D optical scanners can both represent a surface, the datasets are fundamental different and contain different information regarding a part’s surface. Extensive research efforts have been conducted on developing QC tools for each of these datasets individually, very few researches were focused on approaches to take advantage of both 3D point clouds (obtained from technologies such as 3D optical scanners) and digital images (obtained from digital cameras) at the same time. This paper proposes a hybrid approach for surface inspection of additive manufacturing parts through Multilinear Principal Component Analysis (MPCA). This proposed approach is demonstrated with additively manufactured parts, which shows the advantage of combining this information for surface classification.
Modeling for Chemical-Etching Enhanced Pulsed Laser Ablation
Authors: Zhang Xing , Mao Bo , Histed Rebecca , Liao Yiliang 
Published: November 2019

Abstract
Pulsed laser ablation (PLA) under active liquid confinement, also known as chemical etching enhanced pulsed laser ablation (CE-PLA), has emerged as a novel laser processing methodology, which breaks the current major limitation in underwater PLA caused by the breakdown plasma and effectively improves the efficiencies of underwater PLA-based processes, such as laser-assisted nano-/micro-machining and laser shock processing. Despite of experimental efforts, little attention has been paid on CE-PLA process modeling. In this study, an extended two-temperature model is proposed to predict the temporal/spatial evolution of the electron-lattice temperature and the ablation rate in the CE-PLA process. The model is developed with considerations on the temperature-dependent electronic thermal properties and optical properties of the target material. The ablation rate is formulated by incorporating the mutual promotion between ablation and etching processes. The simulation results are validated by the experimental data of CE-PLA of zinc under the liquid confinement of hydrogen peroxide.
Analysis of Polycrystalline Diamond Micro-Grinding Tool Topography Using Image Processing
Authors: Pratap Ashwani , Patra Karali 
Published: November 2019

Abstract
Polycrystalline diamond (PCD) micro-grinding tools are shaped using different electro-discharge machining processes among which wire electro-discharge grinding (WEDG) process is widely accepted due to its capability of producing highly precise, ultra-thin and dimensionally accurate tools. Topographical analysis of the tool surface is inevitable as abrasive cutting edge density and grit protrusion heights affect the cutting process and are equally demanding parameters in modeling of the process. Analysis of micro-grinding tool topography and determining the tool surface statistics have always been a vital challenge due to random positioning and orientation of the abrasives on the tool surface. Current study deals with dressing of polycrystalline diamond micro-tool using wire-electro-discharge grinding and thereafter analysis of tool surface topography using novel image processing technique. In contrast to most of the previous experimental studies based on wheel replication and touch probe data to analyze the conventional grinding tool surface, we develop a sequential methodology using various available image processing algorithm tools and its application on the actual 3D surface data of the miniature sized PCD tool to capture the abrasive density and protrusion heights distribution. It is observed that image processing employing leveling, threshold, watershed algorithm and edge detection provided accurate outlook into the tool surface. Static cutting edge density is found to be 165–170 grits (per mm) and its variation with respect to depth into tool surface is also observed.
Surface Modifications of Titanium With Covalently-Bonded Silver Nanoparticles for Antimicrobial Applications
Authors: Maharubin Shahrima , Shu Xiaomei , Singh Manavi , De los Reyes Benildo , Tan George 
Published: November 2019

Abstract
Formation of biofilm on implant surface is one of the major causes for port-operative infection. Incorporation of antimicrobial silver nanoparticles (AgNPs) on implant surface has been studied as an effective remedy in recent decades. This paper presents a novel AgNPs-titanium composite foil manufactured through covalent attachment of AgNPs for biofilm control. This composite foil was fabricated by a series of chemical reactions including thiol-derivatization and formation of Ag-S covalent bonds. The film structure and properties were characterized through scanning electron microscopy (SEM), Energy dispersive X-ray Spectroscopy (EDS) and surface profiling. The antimicrobial performance was examined against gram positive bacterial strain Staphylococcus aureus. Results indicate that the prepared composite foil effectively reduced bacterial attachment in short term exposure and possess high stability against the release of nanoparticles. This novel antimicrobial composite material has a great potential to be used in the future biomedical instrumentation.
Molecular Dynamics Simulation of Nanoparticle Infiltration During Binder Jet Printing Additive Manufacturing Process: A Preliminary Study
Authors: James Sagil , Navarro Cristian 
Published: November 2019

Abstract
Binder Jetting Process involves binding layers of powder material through selective deposition of a liquid binder. Binder jetting is a fast and relatively inexpensive process which does not require a high-powered energy source for printing purpose. Additionally, the binder jetting process is capable of producing parts with extreme complexities without using any support structures. These characteristics make binder jetting an ideal choice for several applications including aerospace, biomedical, energy, and several other industries. However, a significant limitation of binder jetting process is its inability to produce printed parts with full density thereby resulting in highly porous structures. A possible solution to overcome the porosity problems is to infiltrate the printed structures with low-melting nanoparticles. The infiltrating nanoparticles help fill up the voids to densify the printed parts and also aids in the sintering of the printed green parts. In addition to increasing the density, the nanoparticle infiltration also helps improve the mechanical, thermal and electrical properties of the printed part along with bringing multi-functionality aspect. Currently, there is a lack of clarity of the nanoparticle infiltration process performed to improve the quality of parts fabricated through binder jetting. This research employs Molecular Dynamics simulation techniques to investigate the nanoparticle infiltration during binder jetting additive manufacturing process. The simulation is performed at different operating temperatures of 1400 K, 1500 K, and 1600 K. The study found that the infiltration process is significantly affected by the operating temperature. The infiltration height is found to be highest at the operating temperature of 1600 K while the porosity reduction is found to be maximum at 1500 K. The infiltration kinetics is affected by the cohesion of the nanoparticles causing blockage of channels at higher operating temperatures. The simulation model is validated by comparing with the Lucas-Washburn infiltration model. It is seen that the simulation model deviates from the theoretical prediction suggesting that multiple mechanisms are driving the infiltration process at the nanoscale.
Laser Forming of Metal Foam Sandwich Panels: Effect of Panel Manufacturing Method
Authors: Bucher Tizian , Zhang Min , Chen Chang Jun , Verma Ravi , Li Wayne , Yao Y. Lawrence 
Published: November 2019

Abstract
Sandwich panels with metal foam cores have a tremendous potential in various industrial applications due to their outstanding strength-to-weight ratio, stiffness, and shock absorption capacity. A recent study paved the road towards a more economical implementation of sandwich panels, by showing that the material can be successfully bent up to large angles using laser forming. The study also developed a fundamental understanding of the underlying bending mechanisms and established accurate numerical models.
In this study, these efforts were carried further, and the impact of the foam core structure, the facesheet and foam core compositions, as well as the adhesion method on the bending efficiency and bending limit was investigated. These factors were studied individually and collectively by comparing two fundamentally different sandwich panel types. Thermally-induced stresses at the facesheet/core interface were thoroughly considered. Numerical modeling was carried out under different levels of geometric accuracy, to complement bending experiments under a wide range of process conditions. Interactions between panel properties and process conditions were demonstrated and discussed.
Influence of Coating Spray on Surface Measurement Using 3D Optical Scanning Systems
Authors: Yang Yuhang , Chen Siyuan , Wang Letao , He Jingying , Wang Shang-Ming , Sun Luwen , Shao Chenhui 
Published: November 2019

Abstract
High-resolution 3D measurement is crucial for a wide range of applications in manufacturing. With the recent development of optical technologies, the performance of many 3D scanning systems has entered the practical range for object digitizing, reverse engineering, quality control, and many other manufacturing applications. In order to extend the measurement capability to reflective or transparent surfaces, a common practice for reducing the unwanted reflection and refraction is to coat the surfaces with micro-particle spray. There is, however, limited discussion about the influence of coating spray on the resulted measurement precision of 3D optical scanning systems, and due to lack of standardized procedure for spray coating, the variability caused by different operators in surface measurement remains to be examined. This paper investigates the 3D data acquisition of spray-coated surfaces with a structured-light scanning system through experiments and statistical analysis. Both surface roughness and spatial statistics are used to quantitatively evaluate the characteristics of the 3D measurement system. Gauge R&R study is conducted to determine measurement repeatability and reproducibility. The results demonstrate that both the number of spray pass and the skill of the individual operator can significantly affect the performance of the structured-light scanning system. Other pertinent suggestions for the operation of 3D optical scanning systems with spray coating are also provided.
Bearing Metrics for Health Monitoring of Machine Tool Linear Axes
Authors: Vogl Gregory W. , Galfond Brian C. , Jameson N. Jordan 
Published: November 2019

Abstract
Diagnostics and prognostics of rotating machinery ball bearings is quite mature with an abundance of available methods and algorithms. However, extending these algorithms to other ball bearing applications is challenging and may not yield usable results. This work used a linear axis to study the ability of an inertial measurement unit (IMU), along with nine signal features, to measure changes in geometric error motions due to induced faults on the recirculating ball bearings of two carriage trucks. The IMU data was analyzed with the nine features used for rotating machinery systems, including root-mean-square, standard deviation, and kurtosis. For each stage of degradation, the statistical population and median value of each feature were compared against the population and median for no degradation, to monitor feature changes due to ball damage. Correlation analyses revealed an ability of the standard deviation feature to detect statistically significant changes as small as 0.05 micrometers or 0.5 microradians, corresponding to a total damaged surface area of truck balls of less than 0.1 percent.