scholarly journals WEDM single crater asymmetry

2021 ◽  
Author(s):  
Paulo M. B. Esteves ◽  
Moritz Wiessner ◽  
João V. M. R. Costa ◽  
Maria Sikora ◽  
Konrad Wegener
Keyword(s):  
Aspect Ratio ◽  
Electrical Discharge Machining ◽  
Energy Levels ◽  
High Energy ◽  
Optical Microscope ◽  
Wire Length ◽  
Machined Surface ◽  
Marquardt Algorithm ◽  
Heat Effects ◽  
The Wire

AbstractIn wire electrical discharge machining (WEDM), the erosion is made through a series of overlapped craters. The shape of these craters has a relevant impact on the characteristics of the machined surface, from surface roughness to heat effects during the spark. Current models on EDM process do not represent specific WEDM characteristics, such as radial asymmetry of the crater or geometrical effects on the crater shape. In order to characterize the crater’s dimensions in WEDM, single discharge experiments are performed on polished steel for pulses with different energy levels. A 3D optical microscope is used to map the single craters’ topographies (experimental work). To capture the craters’ dimensions, an ellipsoidal equation is applied with a Levenberg–Marquardt algorithm. The ellipsoidal equation is capable of identifying the dimensions along the wire length, perpendicular to the wire and the depth of the crater. The ratio between the dimension along the wire and the dimension perpendicular to the wire is used to define a crater’s aspect ratio and characterizes its elongation. The aspect ratio of the single craters is found to be dependent on the pulse energy. Low-energy pulses create rounder craters, while high-energy pulses form elongated craters that are longer along the wire length. Such behavior suggests that the crater formation is constricted by the wire geometry, having a preferential direction of growth, along the wire length.

scholarly journals Dynamic Control of Discharge Energy During WEDM for the Purpose of Eliminating Vibrations of the Wire Tool Electrode

2021 ◽  
Vol 29 (4) ◽  
pp. 260-265
Author(s):  
Ľuboslav Straka ◽  
Patrik Kuchta
Keyword(s):  
Electrical Discharge Machining ◽  
Production Systems ◽  
Dynamic Control ◽  
High Strength ◽  
Tool Electrode ◽  
Discharge Process ◽  
Machined Surface ◽  
The Wire ◽  
Wedm Process

Abstract Production in all industry fields is currently affected by new scientific and technical knowledge and the requirements for its rapid deployment. In many cases, the most modern and highly sophisticated technical systems are applied. Simultaneously, fully automated production systems are rather successfully used and progressive production technologies are implemented. In most cases, there is an integral part of a management system that operates the challenging technological processes. These processes would not be executable without the system’s precise control, which provides a suitable precondition for ensuring the high quality of manufactured products. However, the customer’s demanding requirements are not always met. These involve increased requests for the quality of the final product due to the reduction of the tolerance band and application of high-strength materials. This paper aims to describe one of the solutions by which it is possible to achieve a higher quality of the machined surface after wire electrical discharge machining (WEDM). The solution proposes that through dynamic management, the WEDM process eliminates the vibrations of the wire tool electrode and thereby achieves a substantial increase in the quality of the eroded area in terms of its geometric accuracy. With the support of an extensive database of information with precise exchange of information, the proposed system will allow to control the electro discharge process with regard to the optimal way of operation of the electro discharge machine on the basis of individually selected conditions.

Straight Shape Setting of Nitinol Wires by Using a Laser Beam

2015 ◽  
Author(s):  
Carlo Alberto Biffi ◽  
Mauro Coduri ◽  
Riccardo Casati ◽  
Ausonio Tuissi
Keyword(s):  
Laser Beam ◽  
Shape Memory ◽  
High Energy ◽  
Elastic Response ◽  
X Rays ◽  
Wire Length ◽  
Laser Technology ◽  
Production Route ◽  
Thin Wires ◽  
The Wire

Shape setting is a fundamental step in the production route of Nitinol Shape Memory Alloys (SMAs) for the fixing of the functional properties, such as the shape memory effect and the pseudo-elasticity. The conventional method for making the shape setting needs the use of furnaces. In this work laser technology was adopted for performing the straight shape setting on commercially available Nitinol thin wires. The laser beam was moved along the wire length for inducing the functional performances. Calorimetric and pseudo-elastic response of the wires, laser annealed, were studied; high energy X-Rays diffraction was done for studying the evolution of the microstructure texture. It can be stated that the laser technology can realize the shape setting of thin SMA wires with pseudo-elastic properties; the wire performances can be modulated in function of the laser power.

Relationship between Thermal Influence and Magnetic Characteristics in Electrical Discharge Machining of Magnetic Materials

2012 ◽  
Vol 516 ◽  
pp. 575-579 ◽  
Author(s):  
Hideki Takezawa ◽  
Yoshihiro Ichimura ◽  
Tatsuya Suzuki ◽  
Tamao Muramatsu ◽  
Naotake Mohri
Keyword(s):  
Magnetic Flux ◽  
Magnetic Materials ◽  
Flux Density ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
High Energy ◽  
Magnetic Flux Density ◽  
Magnetic Characteristics ◽  
Machined Surface ◽  
Machining Conditions

t is difficult to perform traditional machining, including turning, milling and grinding, of a permanent magnet, which is a functional material, because of magnetic forces. However, electrical discharge machining (EDM), which is a non-contact machining method, has been used for shape machining of magnetic materials. In the EDM process, non-magnetic materials such as copper or graphite are typically used as electrodes. Magnetic materials have a Curie point; therefore, their magnetic flux density reduces when they are heated to a high temperature. Because EDM is a thermal process, it has the potential to control the magnetic flux density of a machined surface. In this study, to clarify the influence of magnetic flux density on a machined surface, the following machining conditions were investigated: (1) the Duty Factor (D.F.) and (2) the input energy of one pulse. A sintered neodymium material was used as the work piece. The magnetic flux density of a cross-section of a machined neodymium magnet was measured. The results showed that the influence of the magnetic flux density was low under low-energy machining conditions. In contrast, for high-energy machining conditions or a high D.F., the magnetic flux density significantly reduced compared to the initial value. These results confirm the importance of machining conditions for EDM of magnetic materials.

Development of Wire Suspended Robot System (ARANEUS 2.0) for Bridge Inspection

10.29007/zw9k ◽  
2020 ◽  
Author(s):  
Kazuhide Nakata ◽  
Kazuki Umemoto ◽  
Kenji Kaneko ◽  
Ryusuke Fujisawa
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Concrete Surface ◽  
Wire Length ◽  
High Definition ◽  
Bridge Inspection ◽  
Robot System ◽  
Inspection Method ◽  
Aerial Vehicle ◽  
The Wire

This study addresses the development of a robot for inspection of old bridges. By suspending the robot with a wire and controlling the wire length, the movement of the robot is realized. The robot mounts a high-definition camera and aims to detect cracks on the concrete surface of the bridge using this camera. An inspection method using an unmanned aerial vehicle (UAV) has been proposed. Compared to the method using an unmanned aerial vehicle, the wire suspended robot system has the advantage of insensitivity to wind and ability to carry heavy equipments, this makes it possible to install a high-definition camera and a cleaning function to find cracks that are difficult to detect due to dirt.

scholarly journals The Use of Lasers in Dental Materials: A Review

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3370
Author(s):  
Emmanouil-George C. Tzanakakis ◽  
Evangelos Skoulas ◽  
Eudoxie Pepelassi ◽  
Petros Koidis ◽  
Ioannis G. Tzoutzas
Keyword(s):  
Energy Levels ◽  
Dental Materials ◽  
High Strength ◽  
Surface Characteristics ◽  
High Energy ◽  
Zirconia Ceramics ◽  
Material Management ◽  
Laboratory Procedures ◽  
Laser Devices ◽  
Exact Point

Lasers have been well integrated in clinical dentistry for the last two decades, providing clinical alternatives in the management of both soft and hard tissues with an expanding use in the field of dental materials. One of their main advantages is that they can deliver very low to very high concentrated power at an exact point on any substrate by all possible means. The aim of this review is to thoroughly analyze the use of lasers in the processing of dental materials and to enlighten the new trends in laser technology focused on dental material management. New approaches for the elaboration of dental materials that require high energy levels and delicate processing, such as metals, ceramics, and resins are provided, while time consuming laboratory procedures, such as cutting restorative materials, welding, and sintering are facilitated. In addition, surface characteristics of titanium alloys and high strength ceramics can be altered. Finally, the potential of lasers to increase the adhesion of zirconia ceramics to different substrates has been tested for all laser devices, including a new ultrafast generation of lasers.

Effects of dietary energy levels on ovarian and uterine expression of IGF-1R and EGFR mRNA in prepubertal gilts

2008 ◽  
Vol 5 (2) ◽  
pp. 159-164
Author(s):  
Li Bo ◽  
Zhang He ◽  
Zhang Jing ◽  
Sun Bo-Xing ◽  
Chen Lu ◽  
...  
Keyword(s):  
Growth Factor ◽  
Energy Intake ◽  
Energy Levels ◽  
Growth Factor Receptor ◽  
High Energy ◽  
Diet Group ◽  
Free Access ◽  
Access To Water ◽  
Moderate Energy ◽  
Epidermal Growth

AbstractNine prepubertal gilts (JunMu No. 1) were randomly allocated into three groups (n=3) and fed with a high-energy diet (Group H), a low-energy diet (Group L), or a moderate-energy diet (Group M) for 14 days. Free access to water was provided throughout the research period. Ovaries and uteri were collected after the energy treatments, and processed for determination of the absolute quantities of insulin-like growth factor receptor (IGF-1R) and epidermal growth factor receptor (EGFR) mRNA, using real-time polymerase chain reaction (PCR). The expression of IGF-1R and EGFR mRNA in ovaries and uteri was significantly ranked as: Group H>Group M>Group L (P<0.05). This result suggests that high energy intake markedly enhanced the ovarian and uterine expression of IGF-1R and EGFR in prepubertal gilts, whereas insufficient energy intake markedly inhibited such expression. IGF-1R and EGFR may be involved in mediating the effects of energy intake on the development of the reproductive system in prepubertal gilts.

Optimization and surface modification in electrical discharge machining of AA 6061/SiCp composite using Cu–W electrode

2015 ◽  
Vol 231 (3) ◽  
pp. 332-348 ◽  
Author(s):  
Balbir Singh ◽  
Jatinder Kumar ◽  
Sudhir Kumar
Keyword(s):  
Process Parameters ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Surface Characteristics ◽  
Electrode Wear ◽  
Material Transfer ◽  
Machined Surface ◽  
Recast Layer Thickness ◽  
Pulse On Time ◽  
Pulse Off Time

This paper presents the experimental investigation on the electro-discharge machining of aluminum alloy 6061 reinforced with SiC particles using sintered Cu–W electrode. Experiments have been designed as per central composite rotatable design, using response surface methodology. Machining characteristics such as material removal rate (MRR), electrode wear ratio (EWR), and surface roughness (SR) have been investigated under the influence of four electrical process parameters; namely peak current, pulse on time, pulse off time, and gap voltage. The process parameters have been optimized to obtain optimal combination of MRR, EWR, and SR. Further, the influence of sintered Cu–W electrode on surface characteristics has been analyzed with scanning electron microscopy, energy dispersive spectroscopy, and Vicker microhardness tests. The results revealed that all the process parameters significantly affect MRR, EWR, and SR. The machined surface properties are modified as a result of material transfer from the electrode. The recast layer thickness is increased at higher setting of electrical parameters. The hardness across the machined surface is also increased by the use of sintered Cu–W electrode.

Ti-6Al-4V Surfaces in SiC Powder Mixed Electrical Discharge Machining

2013 ◽  
Vol 856 ◽  
pp. 226-230 ◽  
Author(s):  
Hamidullah Yaşar ◽  
Bülent Ekmekci
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Dielectric Liquid ◽  
Operational Parameters ◽  
Electrical Parameters ◽  
Machined Surface ◽  
Optical Scanning ◽  
Surface Topographies ◽  
Powder Suspension

The role of suspended particles on Ti-6Al-4V surface in Powder Mixed Electrical Discharge Machining (PMEDM) is studied using SiC powder mixing in water dielectric liquid. Surface modifications due to the additives in dielectric liquid are investigated by means of optical, scanning electron microscopy and energy dispersive spectroscopy. The attachment of added powders and surface topographies interrelated with powder suspension concentration, particle size and electrical parameters such as pulse on duration and current. The influence on discharge transitivity with respect to SiC additives is noticed with pock like features on the surface. The geometry and size of these features indicated a robust dependency with respect to operational parameters and indicated the role of secondary discharges during PMEDM. SiC particles severely transferred from di-electric liquid to machined surface at critical operational parameters and implied that the process could be also used as a surface alloying technique.

scholarly journals Sub-Microstructure of Surface and Subsurface Layers after Electrical Discharge Machining Structural Materials in Water

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1040
Author(s):  
Sergey N. Grigoriev ◽  
Marina A. Volosova ◽  
Anna A. Okunkova ◽  
Sergey V. Fedorov ◽  
Khaled Hamdy ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Structural Materials ◽  
12Kh18n10t Steel ◽  
Mean Deviation ◽  
Water Medium ◽  
Tool Electrode ◽  
Marquardt Algorithm ◽  
Subsurface Layers ◽  
Electrical Wear

The material removal mechanism, submicrostructure of surface and subsurface layers, nanotransformations occurred in surface and subsurface layers during electrical discharge machining two structural materials such as anti-corrosion X10CrNiTi18-10 (12kH18N10T) steel of austenite class and 2024 (D16) duralumin in a deionized water medium were researched. The machining was conducted using a brass tool of 0.25 mm in diameter. The measured discharge gap is 45–60 µm for X10CrNiTi18-10 (12kH18N10T) steel and 105–120 µm for 2024 (D16) duralumin. Surface roughness parameters are arithmetic mean deviation (Ra) of 4.61 µm, 10-point height (Rz) of 28.73 µm, maximum peak-to-valley height (Rtm) of 29.50 µm, mean spacing between peaks (Sm) of 18.0 µm for steel; Ra of 5.41 µm, Rz of 35.29 µm, Rtm of 43.17 µm, Sm of 30.0 µm for duralumin. The recast layer with adsorbed components of the wire tool electrode and carbides was observed up to the depth of 4–6 µm for steel and 2.5–4 µm for duralumin. The Levenberg–Marquardt algorithm was used to mathematically interpolate the dependence of the interelectrode gap on the electrical resistance of the material. The observed microstructures provide grounding on the nature of electrical wear and nanomodification of the obtained surfaces.

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