bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical Formula for Determining the Maximum Straight Length of a Buried Pipeline That Can Prevent Seismic Buckling
Authors: Onuki Shoma , Mitsuya Masaki
Published: January 2021

Buried pipelines must exhibit the appropriate seismic performance to be applied practically and securely. One major pipeline failure mode is buckling caused by seismic ground motion. Buckling typically occurs in straight pipeline sections because seismic axial loads mainly accumulate along straight lines. The design method for defining a maximum straight pipe length to decrease seismic axial loads is known to be effective in preventing buckling. Based on this previous knowledge, this study develops a theoretical formula for estimating the maximum straight length to prevent buckling. The proposed formula is derived using an analytical pipeline model with soil springs under seismic ground motion. Using this analytical model, the seismic loads which are applied to the straight pipe and the pipe connected to the straight pipe are calculated respectively. Then, the formula for the maximum straight length is derived by calculating the straight pipe length where the axial stress in the straight pipe is equal to the yield stress. The proposed formula is validated through finite element analysis. The maximum straight lengths obtained by the theoretical formula are in good agreement with FEM or shorter, thus providing a margin of safety. This work can be useful in designing buried pipelines to prevent buckling failures, thus enabling safer and more viable pipelines.
Effects of Slope Grade on Soil-Pipe Interaction: Full-Scale Experiments
Authors: Katebi Mohammad , Wijewickreme Dharma , Maghoul Pooneh , Roy Kshama
Published: January 2021

In the current industry practice guidelines, the soil restraints to assess the behaviour of pipelines subject to permanent ground displacements are numerically characterized using independent “soil springs”. These guidelines have been primarily generated by considering the typical configurations of buried pipelines in level ground. The assumption of level ground does not always hold true when assessing pipelines located on sloping ground in mountainous areas and riverbanks. This research presents the outcomes from a set of full-scale physical model tests conducted on a pipe buried in slopes. The results highlight the significance of the slope grade effects on soil-pipe interaction. The results are useful as input to modify soil springs accounting for the ground surface inclination.
Joint Strength and its Improvement of Friction Welded Joint Between Ductile Cast Iron and 5052 Al Alloy
Authors: Kimura Masaaki , Yoneda Akira , Kusaka Masahiro , Kaizu Koichi , Hayashida Kazuhiro , Takahashi Tsuyoshi
Published: January 2021

To obtain dissimilar joint for easily making multi-material structures, the characteristics of friction welded joint between ductile cast iron (FCD400) and 5052 Al alloy (A5052) was investigated. The relatively high tensile strength of joint was obtained when that was made with a friction speed of 27.5 s−1, a friction pressure of 20 MPa, a friction time of 1.5 s, and a forge pressure of 270 MPa, respectively. However, this joint had approximately 77% in the tensile strength of the A5052 base metal and that was fractured at the weld interface. Although the weld interface had no intermetallic compound layer, the fractured surface at the A5052 side had some graphite particles that were supplied from the FCD400 side. To improve the joint strength, the graphite particles were reduced from the weld faying surface at the FCD400 side by decarburization treatment. The joint had approximately 96% in the tensile strength of the A5052 base metal and that was fractured between the A5052 side and the weld interface. The joint with high tensile strength as well as the possibility improving the fractured point of that were obtained when those were made with opportune friction welding condition and no graphite particles at the weld faying surface of the FCD400 side.
Proposal of High-Quality Laser Hardening System for Shaft Parts Using Cylindrical Mirror and Ring-Beam Shaped by High-Speed Laser Scan System
Authors: Tanabe Hirotaka , Ogawa Keiji , Nakagawa Heisaburo , Tsukada Hirohito , Goto Yuki
Published: January 2021

Shaft parts are important parts used in almost all machines including automobiles. In addition, extremely high reliability is required since a shaft failure is directly linked to a fatal machine trouble. Therefore, a hardening process is usually conducted to improve strength and wear resistance. In this study, we propose a new laser heat treatment method to produce high-quality and high-accuracy shafts with high efficiency, low cost and low environmental impact. We will also develop a technique to derive the appropriate laser irradiation conditions quickly and systematically for shafts with various shapes and dimensions. There are the other hardening techniques including the electric furnace method and the induction method. These methods require post-processing for deformation correction, whereas the proposed method uses a laser to achieve thermal deformation-free hardening, eliminating the need for the post-processing. As a result, an improvement in yield can be expected due to a reduction of the products that cannot be corrected after heat treatment, which had to be waste disposed with conventional methods. By using our method, the entire circumference of the shaft was hardened by using a ring-shaped laser beam and a cylindrical inner mirror. Here, the ring-shaped laser beam was formed by high-speed scanning of a spot shapelaser. In the present paper, the details of this system were introduced and some experimental results were described.
Developing a Human-Cognition-Based Reverse Engineering Approach
Authors: Tashi  , Ullah A. M. M. Sharif , Kubo Akihiko
Published: January 2021

Conventional reverse engineering uses 3D scanning or image processing technologies to extract the shape information of a given object in terms of point clouds before creating its virtual and real models. It requires complex and user-intensive geometric modeling processes such as noise removal and surface reconstruction. In order to avoid all these complex processes, this paper presents a scanning-free reverse engineering approach defined as a human-cognition-based reverse engineering. The approach consists of four spaces. The first space is defined as a human cognition space wherein the information of a given object is represented using some predefined linguistic expressions. The second space is defined as a point cloud creation space wherein the predefined linguistic expressions are translated to a point cloud model. The third space is defined as a virtual model creation space wherein the point cloud model is converted into a virtual model using a commercially available CAD system. The last space is defined as a real model creation space wherein the virtual model is converted into a real model using 3D printing technology. The efficacy of the proposed approach is demonstrated by performing a case study. The findings will help those who want to simplify the current practices regarding reverse engineering.
Fabrication of an Antireflective Structure on a Lenticular Lens
Authors: Yatagawa Katsuyuki , Nakamura Masato , Ono Masaki , Taniguchi Jun , Hiwasa Shin
Published: January 2021

In our previous study, various lenses with antireflective structures (ARSs) were fabricated by ultraviolet nanoimprint lithography (UV-NIL) and a thin flexible replica mold, which had ARSs. However, in the case of a lens with a large uneven surface such a lenticular lens, it is difficult to transfer an ARS. In this paper, the improvement of the transfer process for a lenticular lens with an ARS is investigated.

A master mold of ARSs was fabricated by irradiating glassy carbon with an oxygen ion beam. A flexible replica mold with ARSs was transferred from the ARS master mold by UV-NIL. In this case, the thickness of the flexible replica mold was 210 μm. A lenticular lens with the reverse shape was also transferred from the original lenticular lens by UV-NIL. To add an ARS to the lenticular lens with the reverse shape, it was covered with a flexible replica mold coated with a UV-curable resin. In addition, the lenticular lens was placed on the back side of the flexible replica mold to contact the lens curve properly. Afterwards, the setting samples were pressed with a roll press and simultaneously UV-cured. After this roll press method was carried out, a lenticular lens with the reverse shape and an ARS was obtained. Using this mold, a lenticular lens with an ARS was replicated by UV-NIL and the reverse-shape mold with an ARS.
Study on Wire Electrochemical Machining of Nickel Base Alloy Using Fine Wire Electrode
Authors: Sasaki Wataru , Natsu Wataru , Xing Huachen
Published: January 2021

Nickel-based alloys represented by Inconel are materials with excellent high-temperature characteristics, and are widely used in the aerospace industry, such as aircraft and rocket engine parts. On the other hand, it is known as a typical difficult-to-cut material. Furthermore, in machining and electric discharge machining (EDM), the machining speed is slow and tool or electrode wear is a big problem. Meanwhile, electrochemical machining (ECM) using electrochemical reaction is not affected by the hardness of the material, does not generate a heat-affected layer on the workpiece surface, and has no tool wear. So, it is considered that ECM is suitable for machining difficult-to-cut materials. Therefore, in this study, focusing on the nickel-based alloy Inconel718 (Alloy718), we conducted a machining experiment using NaNO3 aqueous solution by wire ECM using a thin wire (mainly tungsten) as a tool electrode, and investigated the ECM characteristics. Wire ECM can be machined like wire EDM, and high-efficiency machining is possible by using a pulse power supply. As a result, it was found that increasing the voltage, electrolyte concentration, electrolyte supply pressure, and diameter of wire increases the current flowing between the electrodes and has the effect of promoting machining. In addition to simple cutting, the possibility of being effective not only for grooving but also for cutting complex shapes was shown.
Cutting Characteristics of Hard-Brittle Materials Under Nano/Micro Groove Cutting Using a V-Shape Tool
Authors: Masahiko Yoshino , Hao Shen , Nakagawa Yuki , Abdelkawy Abdallah
Published: January 2021

The cutting characteristics and the critical depth of cut in nano/micro cutting of hard/brittle materials were investigated. A V-shaped single crystal diamond tool with a negative rake angle was used as the tool, and a cutting experiment was conducted by means of the inclined cutting test technique.

The effect of rake angle on specific cutting force was also compared with V-groove cutting model based on simple shear plane. It was found that the cutting force increased and the burrs height increased as the rake angle became negative. and it was considered that the plastic flow influenced on the cutting force. It was also found that the critical cutting depth decreases with the decrease of the rake angle. The result of this experiment showed the opposite tendency to previous studies on the critical depth of cut. This is attributed to that, in the V-type tool cutting, the crack growth by increasing plastic flow is more effective than the suppress of cracks growth by increase of hydrostatic pressure.
Strength Characterization of Adhesive Joint Surface-Modified by Large-Area EB Irradiation
Authors: Omiya Yuya , Toyota Kenji , Nakanishi Ryota , Okada Akira , Shinonaga Togo , Fujii Masahiro
Published: January 2021

With recent improvement in adhesive performance, adhesive joints are used more in various industrial fields. Despite their advantage in connecting dissimilar adherends, adhesive joints are considered not suitable for key components of mechanical structures due to their large scatter in joint strengths. There are many factors that affect the strength of adhesive joint. However, the general bonding factors are (1) mechanical bond, (2) physical bonding, (3) chemical bonding. The adhesion mechanism is complex because these theories occur at same time. Thus, it is necessary to consider the factors separately. And it is important to understand the bonding mechanism on interfaces in adhesive joint and to improve the reliability of the joint strength more. In this study, the tensile strength of single lap joint was measured in order to investigate the influence of various surface treatments and strength characterization of adhesive. Specimens consist of aluminum alloy plates (A6061). Large-area electron beam (EB) and plasma were used for surface treatment. Each one of specimens were examined from the view of wettability, roughness parameter. Compared with unirradiated specimens, other joints improved the wettability and tensile strength. The inference of large-area EB irradiation on adhesive mechanism was discussed.
Investigation of Laser Hardening Forming Method for Thin Steel Plate From a View of Origami Engineering
Authors: Manabe Yuki , Nishida Hiromichi , Onishi Hirokazu , Hirogaki Toshiki , Aoyama Eiichi
Published: January 2021

In recent years, products have been miniaturized and multi-functionalized, and the importance of integration in compact machine tools has increased. In this study, we propose integration via laser hardening forming which combines laser hardening and laser forming on a compact machine toolfor thin steel sheets. For the processing, the deformation and quenching were considered during repeated laser scanning repeated at the same location. In addition, to apply laser quenching forming to origami engineering, a test piece with resilience was prototyped. As a result, problems in repeated laser scanning were clarified, and the tool’s applicability to origami engineering was demonstrated.
Diamond Fly Cutting Applied to Improve Curved Surface Machining by In-Process Measurement and Control on an Ordinary Milling Machine
Authors: Otsubo Tatsuki , Yazawa Takanori , Wang Jinhui , Kato Tomonori
Published: January 2021

To improve the accuracy of the machined surface produced by an ordinary milling machine, a system called workpiece-referred form accuracy control (WORFAC) was developed and confirmed in diamond turning. However, non-rotational symmetric surface structures, such as V-grooves, pyramid structures, F-theta lenses, and other free form surface cannot be machined by diamond turning. We proposed to improve the form accuracy of a machined surface produced by an ordinary milling machine by diamond fly cutting using controlled cutting with reference surface (CCRS), an in-process measurement and control method. Fly cutting is usually used to manufacture ultra-precision microstructures with nanometric surface roughness and submicrometric form accuracy, without the need for subsequent polishing. Nevertheless, a high level of accuracy has only recently been achieved on ultra-precision milling machines. In this study, we verified the effectiveness of fly cutting with CCRS on an ordinary milling machine. CCRS improves machined surface accuracy by controlling the relative displacement between the tool and workpiece. Diamond fly cutting using CCRS was demonstrated to reduce the table motion error on an ordinary milling machine. The experiments of curved surface machining by uncontrolled machining and control machining were conducted, and the effectiveness of improving the circular are machining accuracy of the general-purpose milling machine was confirmed.
High Efficiency Molding by Real-Time Control of Distance Between Nozzle and Melt Pool in Directed Energy Deposition Process
Authors: Aizawa Kengo , Ueda Masahiro , Shimada Teppei , Aoyama Hideki , Yamazaki Kazuo
Published: January 2021

Laser metal deposition (LMD) is an additive manufacturing technique, whose performance can be influenced by a considerable number of factors and parameters. Typically, a powder is carried by an inert gas and sprayed by a nozzle, with a coaxial laser beam passing through the nozzle and overlapping the powder flow, thereby generating a molten material pool on a substrate. Monitoring the evolution of this process allows for a better comprehension and control of the process, thereby enhancing the deposition quality. As the metal additive manufacturing mechanism has not yet been elucidated, it is not clear how process parameters affect material properties, molding accuracy, and molding efficiency. When cladding is performed under uncertain conditions, a molded part with poor material properties and dimensional accuracy is created. In this paper, we propose a method for high efficiency molding by controlling the distance between the head nozzle and the molten pool in real time. The distance is identified by an originally developed sensor based on a triangulation method. According to the distance, the head nozzle is automatically controlled into the optimum position. As a result, an ideal molding process can be generated, so that high efficiency molding and high-quality material properties can be obtained. Experimental results show that continuing deposition at the optimum distance assists in achieving deposition efficiency and dimensional accuracy. According to the specific experimental results of this method, the modeling efficiency was increased by 27% compared to the method without correction, and the modeling was successful with an error within 1 mm.
Development of Friction Stabilization Control Using Genetic Algorithm and Contact Point Control Method
Authors: Yamada Takazumi , Murashima Motoyuki , Umehara Noritsugu , Tokoroyama Takayuki
Published: January 2021

Currently, there are many tribological components that require long life. In the case of unique machines such as satellites and wind turbines, parts replacement and maintenance require huge costs. Generally, machine surfaces get damaged (e.g. wear scar) during operations, which impedes stable sliding [1,2]. We establish a new surface which can avoid the damaged part in order that maintenance-free or energy-efficient mechanical components can be realized. The previous researchers have developed a method which actively controls friction by using a morphing surface. The morphing surface consists of morphing diaphragms and some supportive parts. Inspired by previous research, this study established a new friction stabilization method that controls the contact position when partial damage occurs on the counter surface. We applied genetic algorithm (GA), one of the artificial intelligence technology, to realize efficient contact point control. In order to stabilize friction, we searched for an optimum pattern of contact points that could avoid the damaged parts by applying GA. By repeating this searching method, a contact point pattern that avoids the damaged parts can be found. As results of experiments, we have succeeded in stabilizing friction by searching for contact point patterns that automatically avoid damage in the friction test using GA. However, even if the search is performed efficiently using GA, the calculation times is necessary about 10–20 times. Therefore, it is necessary to shorten the time before the damage is avoided. We report on a method to shorten the search time for the optimal contact point pattern using GA as the latest progress. In this method, some simple contact point patterns are used to roughly identify the locations where damage might be present during some rotations. At the section of creating the 50 contact patterns, this probability of damage existence is used to create the 50 contact patterns that are more likely to avoid the damaged parts. By adding this process before the friction test using GA, we succeeded in reducing the number of calculations from 10–20 times to 2 times.
Molecular Dynamics Study on the Machining of Titanium
Authors: Bhattacharya Ayan , Zhang Xueping , Shivpuri Rajiv
Published: January 2021

Titanium is a popular metal with good strength-weight ratio, high resistance to corrosion and can withstand higher temperatures. Titanium and its alloys are widely used in the aerospace industries. As the experimental tests for titanium are costly and Finite Element Method analysis do not permit observation of deformation defects occurring at the atomistic scale, at shorter time scales, Molecular Dynamics analysis tool has been used to study the machining process at the atomistic scale. The small dimension of workpiece, reduced depth of cut and cutting speed bring up several issues that may not play any significant role in conventional machining but are of significant importance in micro and nano-level cutting process. During Machining, an increase in dislocation density occurs at the machined surface, due to this plastic deformation on these upper layers of the machined surface. Previous work on machining at the nano-scale has been performed for Copper, Aluminum and Silicon with a focus on different potential energy functions, tool life, tool geometry and effect of cutting forces. In this present work, a molecular dynamics simulation study has been performed to investigate evidence of deformation on the machined surface and subsurface layers during machining of monocrystalline titanium workpiece with a rigid diamond tool at nanometric scale using different cutting speeds. The distribution of deformation factors including stress, strain, strain rate, the temperature in the machined surface and sub-surfaces are analyzed at various cutting speeds given the same other conditions.
Detection Scheme of Volume of Repair of Engineering Equipment Based on Line Structured Light
Authors: Liu Bowen , Lu Hong , Wu Zidong , Li Shuo , Liu Qiong
Published: January 2021

When the body, main support and other large metal parts are damaged, welding or surfacing is generally used as the repair method. Measuring volume of repair is a key step before welding repair, because former provides relevant parameters for latter. Line structured light detection is a fast and convenient machine vision detection method, which is suitable for detection tasks in various complex environments and satisfies the requirements of volume of repair of engineering equipment detection. This paper designs a scheme based on line structured light. In this scheme, the parameters of welding repair are obtained by several steps, such as scanning, image processing, light strip center extraction and trend points extraction. Compared with other common methods, this scheme has the advantages of fast detection, easy operation, high cost-performance ratio and easy expansion. especially in combination with welding robots, it can greatly improve the level of automation and reduce the maintenance time.
A Stochastic Optimization Model for a Joint Pricing and Resource Allocation Problem
Authors: Meng Qiunan , Xu Xun
Published: January 2021

In a competitive and volatile market, the price is needed to make in consideration of the uncertain demands of the customers and the limited capacities of enterprises. This requires the coordination decisions on pricing, delivery and resource allocation to increase profit and guarantee service quality for firms. The joint decision on pricing and resource allocation with demand and processing time uncertainty is becoming an issue for a profit-maximizing firm that produces various products. We propose a two-stage model based on stochastic programming to address this joint problem, aiming to maximize profit of products. We present a scenario-simulation approach to describe the stochastic variables; then the deterministic two-stage mixed integer linear programming model is formulated depending on those scenarios. We develop an algorithm by ant colony algorithm to obtain the near-optimal solutions of the models above. The numerical experiments were conducted to validate the proposed models. The results show that the stochastic approach outperforms the deterministic model in the different problem scales and yield the better values of compared metrics. The outcomes also imply that this joint pricing model can provide managerial inspiration for enterprises in the customization environment.
Model and Simulation of Laser Pulse Absorption in Laser-Induced Plasma Micro-Machining (LIPMM)
Authors: Xie Jiaxi , Ehmann Kornel , Cao Jian
Published: January 2021

Direct laser ablation removes material by directly focusing the laser on the material surface so its performance highly depends on the surface condition. Laser-Induced Plasma Micro-Machining (LIPMM) removes the material by focusing an ultrashort laser pulse in an auxiliary dielectric layer above the material and inducing dielectric breakdown to achieve more accurate energy deposition. The physical process of LIPMM can be divided into two stages: pulse absorption and material removal. This work focuses on modeling the pulse absorption stage by implementing the Finite Difference Time Domain (FDTD) method to provide a unified simulation framework for the ultrashort laser-matter interaction. The simulation model can be divided into three steps: 1) the evolution of the laser field, which is described by FDTD with current and a tightly focused beam with Gaussian entry utilized to approximate the unperturbed laser field near focus; 2) the metal absorption of a ultrashort laser pulse, where a two-temperature model is used and the current is described by the Drude model with mean free time approximated by a three stage model and 3) the water breakdown, which is described by Kennedy’s first order model. Combining the above approaches, the unified framework demonstrates its utility on the example of the water-aluminum boundary in the LIPMM process.
Semiconductor Aspects of the Oxyfuel Cutting Torch Preheat Flame: Part I — Measurements Between Torch and Work
Authors: Martin Christopher R. , Pond Teresa , Tomas Jacob , Schmit Jenna , Miguel Erikson , Untaroiu Alex , Xu Kemu
Published: January 2021

This two-part paper presents precise measurements of the ion currents passing between the torch and work piece of the preheat flame of an oxyfuel cutting torch as a means for replacing contemporary sensing suites. Part I shows that the current-voltage characteristic of the flame exhibits sharp discontinuities common to semi-conductors that we study in various configurations including preheat, pierce, cut, and loss-of-cut. Standoff measurements are made by applying a sinusoidal current signal between the torch and work piece while the resulting voltage amplitude is an indication of flame resistance. Uncertainties are estimated to range from 0.5mm to 1mm (.02in to .04in). Signals for ready-to-pierce and precursors for loss-of-cut are also produced due to the generation of secondary ions from chemical activity at the work piece.
Semiconductor Aspects of the Oxyfuel Cutting Torch Preheat Flame: Part II — The Flame’s Internal Electrical Structure
Authors: Martin Christopher R. , Pond Teresa , Tomas Jacob , Schmit Jenna , Miguel Erikson , Untaroiu Alex , Xu Kemu
Published: January 2021

This two-part paper presents precise measurements of the ion currents passing between the torch and work piece of the preheat flame of an oxyfuel cutting torch as a means for replacing contemporary sensing suites. Part II presents the results of a novel spinning disc Langmuir probe technique to construct spatially resolved measurements of the flame’s ion density distribution. A bias voltage is applied to a .254mm diameter wire protruding from a spinning disc, and as the wire is passed through the flame, the measured currents (on the order 10μA) are collected. The process is repeated with incremental wire depths in the flame to construct the entire planar cross-sectional ion density. Measurements reveal intense ion concentrations in the inner cones that rapidly decay by an order of magnitude in the surrounding flow. The outer cone forms a hollow cylinder of weak ion concentration that declines with distance from the inner cones in a manner consistent with recombination.
Effects of Processing Conditions on Laser Direct Deposited Alumina Ceramics
Authors: Pappas John M. , Dong Xiangyang
Published: January 2021

Additive manufacturing (AM) of high-quality inherently brittle ceramics via laser direct deposition, also known as laser engineered net shaping, is challenging due to high thermal gradients, thermally induced cracks, and porosity, typically accompanied by low powder usage efficiency. It is necessary to have an improved understanding of the effects of processing conditions on the fabricated ceramic parts. In this study, alumina ceramics were fabricated with commercial alumina powders. In particular, this paper studied the effect of laser power and scan speed on single track geometries, thin-wall morphology, grain size, density, and powder efficiency during laser direct deposition of alumina ceramics. A single-track parametric study was first conducted to determine the range of processing parameters that produce quality single-tracks and to aid in matching the z-increment with layer thicknesses. The results showed that increased scan speeds promoted significant grain refinement. Average grain size was reduced by nearly 50% when scan speed was increased from 1000 mm/min to 5000 mm/min. On the other hand, densification reached a maximum of 98% at a scan speed of 1000 mm/min with a slight decrease in density was observed at higher speeds. This indicated a trade-off between porosity and grain size when altering the laser scan speed. Significant advantages of using CO2 lasers for AM of ceramics was also demonstrated with powder usage efficiencies reaching nearly 90% under optimized processing conditions.
Research on Chip Formation Mechanism of Laser-Assisted Machining of Fused Silica Based on Variable Laser Angle
Authors: Pan Pengfei , Song Huawei , Xiao Junfeng , Yang Zuohui , Ren Guoqi , Chen Xiao , Xu Jianfeng
Published: January 2021

Laser-assisted machining (LAM) is a promising technology for improving the machinability of hard-to-cut materials. In this study, based on the finite element method (FEM), a cutting model of thermally coupled non-uniform temperature field is established. The chip formation mechanism of fused silica during the laser-assisted machining process is explored from the aspects of laser power and laser incident angle. The results show that as the laser incident angle increases, the continuity of the chip increases gradually. An annular tool holder that can adjust the angle between the laser beam and the tool was designed. And the similar chip morphology obtained by variable-angle cutting experiments verified the effectiveness of the cutting model. Moreover, fracture chips and continuous banded chips are found in both simulation and experiment, which implies that the cutting mechanism works under a hybrid mode of brittle fracture and plastic deformation in the LAM process.
Experimental Investigation of Electrochemical Micro Turning of Ti6Al4V With NaOH Solution
Authors: Das Arnab , Kumar Deepak , Kumar Mohan , Bajpai Vivek
Published: January 2021

Ti6Al4V is a highly favorable material in biomedical, aerospace and many other industries. However, rapid tool wear during machining has made Ti6Al4V into a difficult-to-machine material. Electrochemical machining may be a solution to that challenge. Moreover, high chemical affinity and formation of oxide layer over the surface have limited the application electrochemical machining for Ti6Al4V. In this paper, an experimental approach of electrochemical micro turning of Ti6Al4V has been described. The electrolyte was 10% aqueous solution of NaOH and the tool was SS 310. For each and every experiment workpiece rotational speed and machining time were kept constant. Constant DC voltage was applied and the inter-electrode gap between tool and workpiece was kept constant for each experiment. Experiments were performed using two different levels of applied voltage, axial feed rate and inter-electrode gap. Their effects over MRR and surface roughness have been determined. Additionally, the optimum working condition was determined in order to maximize MRR and minimize surface roughness. For each experiment, acceptable material removal and good surface finish have been achieved. The maximum surface roughness (Ra) was found 1.128 μm in experiment 1. The utilization of NaOH solution has resulted in controlled electrolyzing current, controlled material removal and therefore, good surface finish.
IoT Based Energy Efficiency Monitoring in Stamping Workshop
Authors: Gan L. , Xiong W. , Li L. , Zhu L. , Huang H.
Published: January 2021

Stamping is employed in a wide range of applications including household appliances, automobiles, vessel, and aerospace. Due to the discrete flow energy-intensive processes and dynamic energy changes in stamping production, it has great potential for energy savings. There still lacks an effective method to monitor and analyze the energy efficiency in stamping workshop. To this end, this paper proposes an energy efficiency monitoring and analysis system based on Internet of Things (IoT). The characteristics in stamping workshop are first analyzed, the energy consumption is decomposed, and the makespan is quantified. Besides, energy efficiency indicators of energy efficiency in the press machine, specific energy consumption in the part, and energy efficiency in the workshop are analyzed and defined. Then the detailed information about the energy efficiency monitoring and analysis system as data acquisition, data transmission, data storage, data analysis, and display based on IoT is presented. Finally, a forklift stamping workshop was investigated to validate the effectiveness of the proposed method. The interface and the results of the data analysis showed that the proposed system can monitor the energy efficiency in the stamping workshop comprehensively. Furthermore, potential opportunities for energy consumption reduction and efficient production can be identified.
Numerical Modeling of Powder Gas Interaction for Laser Powder Bed Fusion Process
Authors: Li Xuxiao , Tan Wenda
Published: January 2021

The powder motion induced by the gas flow has been identified as one of the critical phenomena in laser powder bed fusion processes that significantly affects the build quality. However, the gas dynamics and its induced driving forces for the powder motions have not been well quantified. A numerical model is developed to investigate such powder-gas interactions. With a combination of computational fluid dynamics and particle tracking techniques, the model is capable of simulating the transient gas flow field surrounding the powder and the forces exerted on powder surfaces. The interaction between metal powders and a free jet is investigated with the current model. In the simulation results, the entrainment and the ejection motions of powders with respect to the free jet can be predicted. It is found that the driving forces of these motions are majorly contributed by the pressure differences in the gas flow surrounding the powder, and the powders can also interact with the jet to significantly alter the flow field. Quantities which are difficult to measure by experiments are quantified by the simulations, such as the velocity and pressure field in the gas, as well as the subjected forces and torques of powders. Such quantitative information provides insights to the mechanisms of the powder-gas interaction in laser powder bed fusion processes.
Simulating the AM Production Facility: A Configurable Software Tool for Strategic Facility-Level Planning
Authors: Shakirov Eldar , Gee Kaitlyn , Quinlan Haden , Hart A. John , Fortin Clement , Uzhinsky Ighor
Published: January 2021

Additive Manufacturing (AM) — one of several core digital technologies in “Industry 4.0” — is increasingly being deployed in industrial-scale contexts. The successful serial production of end-use polymer and metal components has demonstrated the possibility of AM as a primary production process in several applications. However, one of the principal challenges to greater adoption is a lack of organizational mastery over AM’s implementation in production contexts, and, more specifically, the absence of clear decision-making tools to facilitate exploration of implementation scenarios. To this end, this work proposes the use of a discrete-event simulation-based software modelling tool to investigate the influences of different facility-level planning decisions on techno-economic characteristics of serial production by AM. By changing key parameters, this tool enables users to observe variation in part cost, identify the contributions of individual system elements to part cost, and assess overall system throughput. The tool enables users to identify locally optimal solutions and make corresponding planning decisions, and to explore limiting cases of cost and lead time. In conclusion, we identify the limitations in the current modeling approach, and propose additional directions for future study.
Finite Element Formulation for Modeling Laser Processing
Authors: Hu Ruixiong , Bloomfield Max O. , Shephard Mark S. , Maniatty Antoinette M. , Sikka Kamal
Published: January 2021

A three-dimensional (3D) transient finite element formulation for modeling laser processing is presented, with the capability to simulate both additive manufacturing and laser ablation physics. State variables are introduced to model the phase change phenomenon and to track the phase and phase history throughout the simulation. Temperature dependent material properties are used to capture the nonlinearity of a typical phase change problem. A level set approach is introduced in the subtractive manufacturing simulation, in order to effectively track the rapidly receding surface due to material vaporization and to update the incoming energy distribution for the pulsed laser source on the new geometry. The 3D finite element simulation is implemented in a parallel multi-physics finite element solver, enabling high-performance computation. Simulation results, for both additive and subtractive manufacturing, are acquired, where the size of melt pool and ablation region (width and depth) are predicted quantitatively.
Enhancing Conductivity in 3D Bulk-Embedded Electronics
Authors: Jahangir Md. Naim , Cleeman Jeremy , Malhotra Rajiv
Published: January 2021

Integrating nanoparticle (NP)-based electrically conductive elements inside additive manufactured parts has a high potential for next-generation smart structures. We investigate, a novel technique in which mixed silver nanowires (NW) and nanospheres (NS) are printed as interconnects and sintered using out-of-chamber Intense Pulsed Light (IPL) sintering inside 3D printed thermally sensitive Acrylonitrile Butadiene Styrene (ABS) and Polylactide (PLA) polymer structures. The inclusion of NWs with the typically used NSs is found to realize dual advantages of no thermal damage of the polymers and a that is much lesser resistivity than the state-of-the-art (13.1 μΩ-cm) only 8X higher than bulk silver. Resistivity decreases with a greater percentage of NW content. On the contrary, the NS-only sample didn’t show any conductivity even after IPL sintering because the wavy feature of 3D printed surface didn’t allow NSs to bond. Even though a greater reduction of resistivity is achieved due to IPL, sintering temperature was below 97°C and maximum sintering time reported is 0.75 seconds which cumulatively resulted in damage-free substrates. When dynamic resistivity is analyzed during polymer overprinting on interconnects, four different resistance trends are seen and explained here. Surprisingly, overprinting on the post-IPL interconnect to fully embed the interconnect inside the structure causes a further resistivity reduction to 11.8 μΩ-cm as well.
Analytical Investigation of Varying Deformation Paths Using Microtube Inflation and Axial Tension
Authors: Mamros Elizabeth M. , Kinsey Brad L. , Korkolis Yannis P.
Published: January 2021

Manufacturers invested in a diverse array of industries, ranging from automotive to biomedical, are seeking methods to improve material processing in an effort to decrease costs and increase efficiency. Many parts produced by these suppliers require forming operations during their fabrication. Forming processes are innately complex and involve a multitude of parameters affecting the final part in several ways. Examples of these parameters include temperature, strain rate, deformation path, and friction. These parameters influence the final part geometry, strength, surface finish, etc. Previous studies have shown that varying the deformation path during forming can lead to increased formability. However, a fundamental understanding of how to control these paths to optimize the process has yet to be determined. Adding to the complexity, as the forming process is scaled down for micromanufacturing, additional parameters, such as grain size and microstructure transformations, must be considered.

In this paper, an analytical model is proposed to calculate strain-paths with one or two loading segments and their associated stress-paths. The model is created for investigations of stainless steel 316L using a microtube inflation/tension testing machine. This machine allows for the implementation of two-segment strain-paths through biaxial loading consisting of applied force and internal pressure. The model can be adjusted, based on the desired forming process or available equipment, to output the appropriate parameters for implementation, such as force, displacement, and pressure.
Reducing Variability in Chemical Vapor Deposition of Carbon Nanotubes Based on Gas Purification and Sample Support Redesign
Authors: Tomaraei Golnaz , Abdulhafez Moataz , Lee Jaegeun , Bedewy Mostafa
Published: January 2021

The synthesis of vertically aligned carbon nanotubes (CNTs), also referred to as CNT forest, by chemical vapor deposition (CVD) is an intricate process that is sensitive to multiple factors other than control of temperature, pressure, and gas flows. In particular, growth is highly sensitive to factors like ambient humidity, as well as small quantities of oxygen-containing species and carbon deposits inside the reactor. These typically uncontrolled factors significantly affect growth reproducibility and hinders the fundamental study of process-structure-property relationship for these emerging materials. Accordingly, universally applicable design modifications and process steps toward improve growth consistency are sought after. In this study, we introduce two new modifications to our custom-designed multizone rapid thermal CVD reactor and demonstrate their impact on growth: (1) reconfiguring the inlet gas plumbing to add a gas purifier to the helium (He) line, and (2) designing a new support wafer for consistent loading of substrates. We use statistical analysis to test the effectiveness of these modifications in improving growth and reducing variability of both CNT forest height and density. Analysis of our experimental results and hypothesis testing show that combining the implementation of He purifier with the redesigned support wafer increases forest height and reduces the variability in height (17-folds), both at statistically significant and practically significant levels.
Analysis of a Multi-Material Bone Plate and its Effect on Interfragmentary Strain for Bone Remodeling Processes
Authors: Hossain Anamul , Tipper Joanne L. , Wei Dongbin
Published: January 2021

The success of bone repair using an internal fracture fixation technique is critically dependent on the stability and biological process between the fragmented bones. However, the currently used bone plates mainly focus on stability rather than biology of healing, which subsequently (a) results in significant stress-shielding effects and (b) prevents stress from transferring from the bone plate to the bone during the healing process. This study proposes a novel design of a bone plate for the fixation of long fractured bones, which can mitigate these disadvantages to strike a balance between stability and biology. The new multi-material design adopts stainless steel (SS316L) and magnesium alloy (AZ31B) of three thicknesses such as SS316L (1mm)-AZ31B (2mm), SS316L (1.5mm)-AZ31B (1.5mm), and SS316L (2mm)-AZ31B (1mm). The mechanical properties (bending stiffness and moment) of the bone plates were evaluated according to the ASTM: F382-17 standard. Static corrosion tests were conducted in Hank’s Balanced Salt Solution (HBSS) at 37.5 °C. Compared with those of the original (non-corroded) bone plates, the maximum load-carrying capacities of the corroded bone plates decreased from 670 N to 495 N, 891 N to 518 N, and 928 N to 709 N in the case of SS316L (1mm)-AZ31B (2mm), SS316L (1.5mm)-AZ31B (1.5mm), and SS316L (2mm)-AZ31B(1mm), respectively. Digital image correlation was utilized to evaluate the inter-fragmentary strain (IFS) in the physical model of fractured bone plates. The IFS increased from 0.526 to 0.815, 0.484 to 0.784, and 0.455 to 0.533 in the case of SS316L (1mm)-AZ31B (2mm), SS316L (1.5mm)-AZ31B (1.5mm), and SS316L (2mm)-AZ31B (1mm), respectively, when a load of 200 N was applied. An optimized design of the bone plate of SS316L and AZ31B for granulation tissue formation based on Perren’s theory and IFS was successfully proposed.
Comparison of Conventional and Ultrasonic Drilling on Cutting Force in Porcine and Human Femur
Authors: Singh Ravinder Pal , Pandey Pulak Mohan
Published: January 2021

Bone fractures are common in human beings, and the surgical operation performed to repair the fractured bone includes the drilling process. Axial cutting force during drilling plays an important role for success in osteosynthesis. Many processes like water jet machining, laser drilling, ultrasonic drilling, two phase drilling and rotary ultrasonic bone drilling (RUBD), have been developed to minimize the cutting force during orthopedic drilling. In the present work, a novel operation theatre compatible ultrasonic assisted rotary bone drilling machine prototype have been designed and fabricated in an attempt to reduce the cutting forces produced during orthopedic drilling. The experimental test were performed on fresh porcine bone and human femur. A comparative study was carried out between RUBD and Conventional drilling (CD), to find out the influence of rotational speed, drilling tool feed rate and drill diameter, on the cutting force produced during the drilling. The study of chip produced in RUBD and CD was also carried out with the help of scanning electron microscopy images. The result obtained by the developed machine showed that the cutting force obtained in human femur was greater (20–25 %) than porcine femur due to its greater hardness and RUBD process produced lower cutting force (20–30 %) than CD for both types of bone. The experimental results showed the increase in cutting force with decreasing rotational speed and increasing feed rate and drill diameter.
A Novel Approach to Determine the Cutting Temperature Under Consideration of the Tool Wear
Authors: Bergs Thomas , Peng Bingxiao , Schraknepper Daniel , Augspurger Thorsten
Published: January 2021

In metal cutting process, modeling and predicting the tool wear development has been researched for decades. Many efforts have been made to study the cutting temperature as an indicator for the tool wear behavior. However, the determination of the cutting temperature in the critical contact area in process is still a challenge.

In order to build temperature-dependent tool wear models, the temperature distribution of the workpiece was captured in this paper by an infrared thermography in orthogonal cutting of Direct Aged Inconel 718 with cemented carbide cutting tool WC-15Co. Instead of studying the temperature in critical cutting zone directly, the workpiece temperature distribution around the flank wear surface was determined inversely with the analytical Jaeger-solution based on the experimental data. The determined maximum cutting temperature on the flank wear surface has been successfully verified by FEM chip formation simulations. By means of this inverse approach, the cutting temperature on the flank surface can be determined as a function of tool wear VB. The experimental results showed that the cutting temperature increased with the increase of the tool wear VB. By means of this method, the temperature on the flank wear surface can be used as an important physical indicator to model and predict the tool wear development in future work.