Energy aspects and workpiece surface characteristics in ultrasonic-assisted cylindrical grinding of alumina–zirconia ceramics

2015 ◽  
Vol 90 ◽  
pp. 16-28 ◽  
Author(s):  
Ali Zahedi ◽  
Taghi Tawakoli ◽  
Javad Akbari
Keyword(s):  
Surface Characteristics ◽  
Zirconia Ceramics ◽  
Workpiece Surface ◽  
Cylindrical Grinding ◽  
Ultrasonic Assisted ◽  
Energy Aspects

Ultrasonic-Assisted Cylindrical Grinding of Alumina-Zirconia Ceramics

2013 ◽  
Author(s):  
Taghi Tawakoli ◽  
Javad Akbari ◽  
Ali Zahedi
Keyword(s):  
Ultrasonic Vibration ◽  
Surface Characteristics ◽  
Zirconia Ceramic ◽  
Zirconia Ceramics ◽  
Workpiece Material ◽  
Cylindrical Grinding ◽  
Ultrasonic Assisted ◽  
The Subject ◽  
Set Up ◽  
Successful Innovation

Due to its vast applications and stochastic nature, grinding has been the subject of investigations and modifications for decades. Applying ultrasonic vibration in grinding has been a successful innovation introducing benefits such as reduced forces and temperature, improved surface quality, and making higher removal rates possible. In this work a set-up is developed for utilizing ultrasonic vibrations in cylindrical grinding. This is done by rotating and simultaneously vibrating the workpiece material. The set-up is used for cylindrical grinding of Alumina-zirconia ceramic as a difficult-to-grind and widely used industrial ceramic. Optimized parameters for efficient grinding and surface characteristics of the ground ceramic are investigated and the effects of ultrasonic vibration are declared.

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.

Analysis of the Effect of Open and Close Angle of Workpiece Surface on Contour Error

2017 ◽  
Author(s):  
Qingzhao Li ◽  
Wei Wang ◽  
Hai Li ◽  
Yunfeng Jiang ◽  
Zhiyong Song
Keyword(s):  
Manufacturing Industry ◽  
Rotation Axis ◽  
Hot Spot ◽  
Surface Characteristics ◽  
Contour Error ◽  
Workpiece Surface ◽  
Special Surface ◽  
Tool Trajectory ◽  
Five Axis ◽  
Complicated Surface

The machining of complicated surface is a hot spot in manufacturing industry in nowadays. The complicated surfaces should be machined with five-axis machine tools because of its geometric characteristics. In this paper, the characteristic of workpiece surface called open and close angle of surface is defined. The transition area from open angle to close angle will cause the twist and singularity of the surface. The twist mainly affects the principle errors of surface. And the singularity will cause the mutation of rotation axis movement and make an influence on the contour errors. To test the influence of the open and close angle on the contour error, a workpiece with special surface characteristics is designed. With the theoretical, simulational and experimental analyses, the influence law from the open and close angle is found out. The conclusion can be helpful for the tool trajectory planning.

scholarly journals Studies on the Potential of Nonmodified and Metal Oxide-Modified Coal Fly Ash Zeolites For Adsorption of Heavy Metals and Catalytic Degradation of Organics for Waste Water Recovery

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 778 ◽  
Author(s):  
Silviya Boycheva ◽  
Denitza Zgureva ◽  
Simona Miteva ◽  
Ivan Marinov ◽  
Dominika Behunová ◽  
...  
Keyword(s):  
Fly Ash ◽  
Magnetic Nanoparticles ◽  
Coal Fly Ash ◽  
Surface Characteristics ◽  
Water Recovery ◽  
X Ray Diffraction ◽  
Wet Impregnation ◽  
Impregnation Technique ◽  
Monolayer Adsorption ◽  
Ultrasonic Assisted

A nanocrystalline zeolite of Na-X type (CFAZ) was synthesized by ultrasonic-assisted double stage fusion-hydrothermal alkaline conversion of lignite coal fly ash. Modified CFAZ with magnetic nanoparticles (MNP-CFAZ) was obtained by adding presynthesized magnetic nanoparticles between the synthesis stages. CFAZs loaded by particles of copper (Cu-CFAZ) and cobalt (Co-CFAZ) oxides were prepared by postsynthesis modification of the parent CFAZ, applying a wet impregnation technique. The parent and modified CFAZs were examined for their phase composition by X-ray diffraction, morphology by scanning electron microscopy, and surface characteristics by N2 physisorption. Comparative studies have been carried out on the adsorption capacity of the starting CFAZ and its derivatives with respect to Cd2+- and Pb2+-ions from aqueous solutions. Adsorption isotherms of Cd2+-ions on the studied samples were plotted and described by the adsorption equations of Langmuir, Freundlich, Langmuir–Freundlich, and Temkin. The best correlation between the experimental and model isotherms for the parent and modified CFAZ was found with the Langmuir linear model, assuming a monolayer adsorption mechanism. Parent and modified CFAZs were also studied as catalysts for heterogeneous thermal Fenton oxidation of methylene blue. At 90 °C, the higher catalytic activity exhibits the nonmodified sample, but with the decrease in temperature to 60 °C, the modified samples are more effective catalysts.

Migration of Materials during Finishing Micro-EDM of Tungsten Carbide

2010 ◽  
Vol 443 ◽  
pp. 681-686 ◽  
Author(s):  
Muhammad Pervej Jahan ◽  
Mustafizur Rahman ◽  
Yoke San Wong
Keyword(s):  
Tungsten Carbide ◽  
Surface Defects ◽  
Surface Characteristics ◽  
Lower Amount ◽  
Tool Electrode ◽  
Micro Edm ◽  
Tungsten Electrode ◽  
Machined Surface ◽  
Workpiece Surface ◽  
Carbon Migration

Present study aims to investigate the migration of materials onto the surface of workpiece and electrode during fine-finish die-sinking and milling micro-EDM of tungsten carbide using pure tungsten electrode. The effect of materials transfer on the machined surface characteristics is also presented. The machined surfaces have been examined under scanning electron microscope (SEM) and energy dispersive X-ray (EDX) in order to investigate the changes in chemical composition due to the migration of materials. It has been observed that materials from both workpiece and electrode transfer to each other depending on machining conditions and discharge energy. A significant amount of carbon migrates to both electrode and workpiece surface due to the decomposition of dielectric hydrocarbon during breakdown. The migration occurs more frequently at lower gap voltages during finish die-sinking micro-EDM due to low spark gap and stationary tool electrode. Milling micro-EDM suffers from lower amount of carbon migration and fewer surface defects which improve the overall surface finish and reduce surface roughness significantly.

scholarly journals Optimization of parameters in cylindrical and surface grinding for improved surface finish

2018 ◽  
Vol 5 (5) ◽  
pp. 171906 ◽  
Author(s):  
Dinesh Kumar Patel ◽  
Deepam Goyal ◽  
B. S. Pabla
Keyword(s):  
Surface Roughness ◽  
Surface Integrity ◽  
Surface Finish ◽  
Surface Characteristics ◽  
Surface Grinding ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Cylindrical Grinding ◽  
Grinding Parameters ◽  
Wheel Material

Surface integrity has attracted the attention of researchers for improving the functional performance of engineering products. Improvement in surface finish, one of the important parameters in surface integrity, has been attempted by researchers through different processes. Grinding has been widely used for final machining of components requiring smooth surfaces coupled with precise tolerances. Proper selection of grinding wheel material and grade with grinding parameters can result in an improved surface finish and improved surface characteristics. The present work reports the study of the effect of grinding parameters on surface finish of EN8 steel. Experiments were performed on surface grinding and cylindrical grinding for optimization of grinding process parameters for improved surface finish. Grinding wheel speed, depth of cut, table feed, grinding wheel material and table travel speed for surface grinding operation, and work speed for cylindrical grinding operation were taken as the input parameters with four types of grinding wheels (Al 2 O 3 of grades K and L, and white alumina of grades J and K). The surface roughness was taken as an output parameter for experimentation. The grinding wheel material and grade have been observed to be the most significant variables for both cylindrical grinding and surface grinding. Surface roughness in the case of surface grinding is better compared to that of cylindrical grinding, which can be attributed to vibrations produced in the cylindrical grinding attachment. Surface roughness ( R a ) values of 0.757 µm in cylindrical grinding and 0.66 µm in surface grinding have been achieved.

Experimental Study on Ultrasonic Vibration Dressing Wheel

2010 ◽  
Vol 135 ◽  
pp. 260-264
Author(s):  
Dao Hui Xiang ◽  
Xin Tao Zhi ◽  
Guang Xi Yue ◽  
Bo Zhao ◽  
Q.T. Fan
Keyword(s):  
Surface Quality ◽  
Ultrasonic Vibration ◽  
Ground Surface ◽  
Surface Characteristics ◽  
Axial Direction ◽  
Grinding Wheel ◽  
Workpiece Surface ◽  
Surface Burn ◽  
Grinding Conditions ◽  
Strict Requirement

Excellent wheel dressing technology can ensure the ground surface quality effectively. Because precision machining has a strict requirement on the wheel dressing, the wheel dressing with ultrasonic vibration was adopted, and the device of ultrasonic vibration dressing was also designed in this paper. On the base of analysis mechanism of ultrasonic vibration dressing wheel, the grinding experiment was carried out in different dressing conditions. The surface characteristics of ultrasonic dressing wheel and the influence of different dressing parameters on the workpiece surface quality were studied. Furthermore, the optimal dressing parameters have been obtained. The experiment results indicate that the micro cutting edge of grinding wheel distribute sparsely in circumferential directional but densely in axial direction in the condition of ultrasonic dressing, and it is particular characteristic of ultrasonic dressing. When the dressing and grinding conditions are suitable, the workpiece surface roughness can be reduced, but the conditions are not arbitrary. At the same time, the workpiece surface burn can be effectively reduced, even if the larger grinding depth is used during the grinding process.

scholarly journals Parametric Investigation of EP To Enhance Surface Characteristics of Maraging Steel With Organic Electrolyte

2021 ◽  
Author(s):  
Abhinav Kumar ◽  
Suraj Kumar ◽  
Manas Das
Keyword(s):  
Surface Roughness ◽  
Maraging Steel ◽  
Linear Sweep Voltammetry ◽  
Surface Characteristics ◽  
Polished Surface ◽  
Surface Reflectance ◽  
Spectroscopy Analysis ◽  
Initial Value ◽  
Workpiece Surface ◽  
Metal Oxide Layer

Abstract Maraging steel 300 is widely used in aircraft, tools, and automotive industries, which requires a polished surface for better performance. In conventional methods of polishing, the abrasives directly contact the workpiece surface and deteriorate its property. Thus, a non-conventional method like Electropolishing (EP), is utilized to finish maraging steel with acetic acid (99.7 wt.%) and perchloric acid (70 wt.%) mixed in the volume of 3:1. Linear sweep voltammetry (LSV) is performed to determine the passive region that gives the best electropolishing performance. Different parameters, namely temperature, agitation, and polishing time and their effect on surface roughness and surface reflectance, are observed during EP. The optimized process parameters which give the best EP performance are the temperature at 60ºC, rotation of magnetic stirrer at 400 rpm, and polishing time of 6 minutes. An improvement of 56% in surface roughness and 60% in surface reflectance from its initial value of 21% is observed. EP makes the surface hydrophilic as the contact angle changes from 111.2º to 68.6º. Energy-Dispersive X-Ray Spectroscopy analysis suggests that after EP, a metal oxide layer forms on the surface which helps in increasing corrosion resistance.

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