Friction Coefficient of Nano-Ceramic Polished by Oxide Film on ELID Grinding Wheel

2013 ◽  
Vol 669 ◽  
pp. 91-94 ◽  
Author(s):  
Ji Cai Kuai
Keyword(s):  
Friction Coefficient ◽  
Oxide Film ◽  
Normal Force ◽  
Tangential Force ◽  
Grinding Wheel ◽  
Nano Materials ◽  
Dynamic Changes ◽  
Bonding Agents ◽  
Elid Grinding ◽  
Feeding Speed

The dynamic changes of the friction properties of the oxide film are characterized by the dynamic changes of the ELID grinding force. The tangential force and normal force are used to represent the friction coefficient in order to obtain the accurate real-time friction coefficient of oxide film. Therefore, the friction coefficient of various grinding wheels with different bonding agents, various grinding parameters, various grinding materials (nano- Al2O3 ceramic, nano ZrO2 ceramic and ordinary ZrO2 ceramic), and ELID grinding and ordinary grinding can be further studied. The results show that: the friction coefficient of the oxide film on the bronze-based grinding wheel is greater than that composed by iron; the friction coefficient of the oxide film decreases with the increase in grinding depth and feeding speed; the friction coefficient of the oxide film and nano-materials is smaller than that of the oxide film and ordinary materials; the transformation from γ-Fe2O3 to α-Fe2O3 in oxide film and the elastic deformation of the oxide film caused by the high-temperature of grinding may make the friction coefficient of ELID grinding greater than that of ordinary grinding, so the oxide film contains better property of friction and polishing. Therefore, excellent surface quality is easier to be obtained by it compared with the ordinary grinding technology.

Forming Mechanism of Composite Abrasive Grains in Oxide Film on ELID Wheel and its Microstructure

2016 ◽  
Vol 709 ◽  
pp. 77-81 ◽  
Author(s):  
Ji Cai Kuai ◽  
Cheng Ran Jiang ◽  
Jiang Wei Wang
Keyword(s):  
Oxide Film ◽  
Grinding Wheel ◽  
Compound Structure ◽  
Wheel Surface ◽  
Forming Mechanism ◽  
Elid Grinding ◽  
Abrasive Grains ◽  
Shaped Crack

In this paper we analyze the forming mechanism of composite abrasive grains in oxide film on ELID grinding wheel surface, By using composition information and by taking advantage of microscale structure, we have investigated that abrasive grains surface is covered by a layer of oxide film and the fresh oxide film is loose and porous like turtle shaped crack when crushed and dried. The elements of oxide film consist of α-Fe2O3 with sphere grain of 5-50nm. This phenomena is demonstrated that the composite abrasive grains in oxide film is a compound structure which is centered by abrasive grains, with α-Fe2O3,Fe (OH)3 surrounded.

Experimental study on the characteristic and function of oxide film formed on grinding wheel in ELID precision grinding

2019 ◽  
Vol 72 (5) ◽  
pp. 549-555
Author(s):  
Jia-Bo Zhang ◽  
Yang Yang ◽  
Xiao-Hui Zhang ◽  
Jia-Liang Guan ◽  
Li-Yan Zheng ◽  
...  
Keyword(s):  
Oxide Film ◽  
Formation Rate ◽  
Combination Method ◽  
Grinding Wheel ◽  
Precision Grinding ◽  
Content Type ◽  
Elid Grinding ◽  
Grinding Fluid ◽  
Film Forming ◽  
And Function

Purpose The purpose of this study is to investigate the characteristic and function of oxide film formed on grinding wheel in electrolytic in-process dressing (ELID) precision grinding and improve the quality of ELID grinding. Design/methodology/approach Dynamic film forming experiments were carried out with a simulation device close to the actual processing conditions. Then, the ELID grinding experiments of bearing rings were performed using grinding wheels with good film forming effect. The experiment was designed by quadratic regression general rotation combination method. The influence of grinding depth, electrolytic voltage, duty cycle and grinding wheel linear speed on grinding effect is analyzed. Findings A mathematical model for the formation rate of oxide film was established. The experiments show that the composition of grinding wheel and grinding fluid, as well as the electrical parameters, influence the film forming effect. Thus, the oxide film plays an important role in ELID grinding. Originality/value This study provides a reference for the design and selection of grinding wheel and grinding fluid and the setting of process parameters in ELID grinding.

Adhesion Model and Shedding Limit's Identification of the Oxide Film on the Surface of ELID Grinding Wheel

2014 ◽  
Vol 900 ◽  
pp. 557-560 ◽  
Author(s):  
Ji Cai Kuai
Keyword(s):  
Oxide Film ◽  
Adhesion Strength ◽  
Grinding Force ◽  
Adhesion Property ◽  
Cemented Carbide ◽  
Grinding Wheel ◽  
Strength Model ◽  
Elid Grinding ◽  
Adhesion Model

The adhesion property of oxide film has great effects on the grinding quality and efficiency of ELID grinding. In this paper, adhesion strength model of oxide film is established, ELID grinding is conducted to nanometric cemented carbide and ordinary cemented carbide, ELID grinding force is measured, adhesive stress is calculated and the correctness of adhesion model is verified. The results show that the adhesion strength of oxide film is relatively greater, the transition from γ-Fe2O3to α-Fe2O3in the oxide film is relatively fuller and the polishing performance is relatively better while the grinding depth is smaller; with the deepening of grinding, the adhesion strength of oxide film reduces, the composition of the oxide film that transforms into α-Fe2O3is less and the polishing ability reduces. The adhesion model of oxide film well reflects the adhesion property of oxide film, and the application of this model can represent the distribution, shedding and updating of the oxide film on the surface of grinding wheel.

Thermoelastic Modeling of Rotor Response With Shaft Rub

2010 ◽  
Vol 77 (6) ◽  
Author(s):  
S. Ziaei-Rad ◽  
E. Kouchaki ◽  
M. Imregun
Keyword(s):  
Friction Coefficient ◽  
Critical Speed ◽  
Normal Force ◽  
Contact Point ◽  
Tangential Force ◽  
Bending Moment ◽  
Contact Forces ◽  
Mass Unbalance ◽  
Deceleration Rate ◽  
The Time Domain

This paper studies the effects of shaft rub on a rotating system’s vibration response with emphasis on heat generation at the contact point. A 3D heat transfer code, coupled to a 3D vibration code, was developed to predict the dynamic response of a rotor in the time domain. The shaft bow is represented by an equivalent bending moment and the contact forces by rotating external forces. The seal ring is modeled as a linear spring, which exerts a normal force to the rotor. The tangential force is then calculated as the product of the normal force with the friction coefficient. Stable or unstable spiraling and oscillating modes were seen to occur in well defined shaft speed zones. In the main, for the configurations studied, the shaft vibration was found to be unstable for speeds below the first critical speed and stable for speeds above the first critical speed. Limit cycle behavior was observed when the phase angle between the unbalance force and the response was around 90 deg. The vibration behavior with rub during startup and shutdown was studied by considering the effects of acceleration/deceleration rate, friction coefficient, and mass unbalance. It was found that friction coefficient and increasing mass unbalance amplified the rub effects while acceleration/deceleration rate reduced it.

Discovery of α-Fe2O3 in the Oxide Film on ELID Grinding Wheel

2014 ◽  
Vol 1061-1062 ◽  
pp. 446-449 ◽  
Author(s):  
Ji Cai Kuai
Keyword(s):  
Oxide Film ◽  
Experimental Verification ◽  
Theoretical Study ◽  
Electrochemical Process ◽  
Grinding Wheel ◽  
Transformation Mechanism ◽  
X Ray ◽  
Elid Grinding

This paper conducted a theoretical study on the generation and transformation mechanism of α-Fe2O3in the oxide film and an experimental verification of the presence of it. Firstly, the electrochemical process of the generation and transformation of α-Fe2O3in the oxide film was analyzed, followed by the measurement of the content of it in the oxide film using X-ray diffractometer.

Manufacturing Technology of α-Fe Bonded Grinding Wheel Free Abrasive

2018 ◽  
Vol 780 ◽  
pp. 111-115 ◽  
Author(s):  
Ji Cai Kuai ◽  
Dmitrii V. Ardashev ◽  
Jia Qi Zhang ◽  
Hua Li Zhang
Keyword(s):  
Oxide Film ◽  
High Surface ◽  
Grinding Wheel ◽  
Mirror Surface ◽  
Precision Grinding ◽  
Abrasive Particles ◽  
Elid Grinding ◽  
Abrasive Grain ◽  
Ultra Precision ◽  
Free Abrasive

ELID ultra-precision grinding mirror surface can achieve nanometer precision. However, after the grinding wheel passivates the abrasive particles in electrolysis, it is easy to scratch the ultra-precision ELID grinding surface into the grinding process. In order to solve this problem, a non-abrasive grain α-Fe bonded grinding wheel is propose, which contains no abrasive particles. After electrolysis, oxide film is formed on the surface of the wheel. In ultra-precision ELID grinding, there is no abrasive particles involved, only the polishing effect of oxide film. There is no need to worry about the scratching of exfoliated abrasive particles that have been machined on ultra-precision ELID surfaces. Thus achieving extremely high surface accuracy.

Study of α-Fe2O3 formation and its measurement in oxide films of wheel surface during ELID grinding process

2017 ◽  
Vol 31 (04) ◽  
pp. 1750025 ◽  
Author(s):  
Jicai Kuai ◽  
Dmitrii V. Ardashev ◽  
Huali Zhang
Keyword(s):  
Oxide Film ◽  
Spectrum Analysis ◽  
Ir Spectrum ◽  
Oxide Films ◽  
Grinding Wheel ◽  
Vibration Band ◽  
Wheel Surface ◽  
Characteristic Absorption Band ◽  
Forming Mechanism ◽  
Elid Grinding

This paper presents the study of forming mechanism of [Formula: see text]-Fe2O3 in oxide films on electrolytic in-process dressing (ELID) grinding wheel surface. To investigate the component content and the microtopography of oxide films, XRD, XPS, IR spectrum analysis, SEM, and TEM measurements are performed on ELID grinding wheels. In XRD test results, the characteristic absorption band of [Formula: see text]-Fe2O3 is found in the oxide film. XPS tests show that there is full of ferrous iron and oxygen element in the oxide film. Also, the characteristic spectral line of XPS is identical to the standard spectrum of [Formula: see text]-Fe2O3. Several vibration peaks (471, 1029, 1384, 1630, 3430) are observed by IR spectrum analysis. It can be easily seen by contrast with the standard photographs that the vibration peak of 1029 is of Fe-O vibration band in IR spectrum of [Formula: see text]-Fe2O3 powder. Therefore, these measurement results confirm the existence of [Formula: see text]-Fe2O3 in the oxide films, and explain the polishing effect of oxide films during ELID grinding. The fresh oxide film is porous and moisture rich. However, the oxide film after squeezing to dry is investigated by SEM imaging to present tortoiseshell cracks. Geometrically, [Formula: see text]-Fe2O3 appears to be nearly spherical with particle size around 5–50 nm. This indicates fine polishing improvement by oxide films, and is identified as the mechanism responsible for excellent surface quality by ELID grinding.

scholarly journals Effect of Water-Based Nanolubricants in Ultrasonic Vibration Assisted Grinding

2018 ◽  
Vol 2 (4) ◽  
pp. 80 ◽  
Author(s):  
Mir Molaie ◽  
Ali Zahedi ◽  
Javad Akbari
Keyword(s):  
Surface Roughness ◽  
Specific Energy ◽  
Material Removal ◽  
Normal Force ◽  
Tangential Force ◽  
Process Efficiency ◽  
Multiwall Carbon Nanotube ◽  
Ultrasonic Vibrations ◽  
Mql Grinding ◽  
Water Based

Currently, because of stricter environmental standards and highly competitive markets, machining operations, as the main part of the manufacturing cycle, need to be rigorously optimized. In order to simultaneously maximize the production quality and minimize the environmental issues related to the grinding process, this research study evaluates the performance of minimum quantity lubrication (MQL) grinding using water-based nanofluids in the presence of horizontal ultrasonic vibrations (UV). In spite of the positive impacts of MQL using nanofluids and UV which are extensively reported in the literature, there is only a handful of studies on concurrent utilization of these two techniques. To this end, for this paper, five kinds of water-based nanofluids including multiwall carbon nanotube (MWCNT), graphite, Al2O3, graphene oxide (GO) nanoparticles, and hybrid Al2O3/graphite were employed as MQL coolants, and the workpiece was oscillated along the feed direction with 21.9 kHz frequency and 10 µm amplitude. Machining forces, specific energy, and surface quality were measured for determining the process efficiency. As specified by experimental results, the variation in the material removal nature made by ultrasonic vibrations resulted in a drastic reduction of the grinding normal force and surface roughness. In addition, the type of nanoparticles dispersed in water had a strong effect on the grinding tangential force. Hybrid Al2O3/graphite nanofluid through two different kinds of lubrication mechanisms—third body and slider layers—generated better lubrication than the other coolants, thereby having the lowest grinding forces and specific energy (40.13 J/mm3). It was also found that chemically exfoliating the graphene layers via oxidation and then purification prior to dispersion in water promoted their effectiveness. In conclusion, UV assisted MQL grinding increases operation efficiency by facilitating the material removal and reducing the use of coolants, frictional losses, and energy consumption in the grinding zone. Improvements up to 52%, 47%, and 61%, respectively, can be achieved in grinding normal force, specific energy, and surface roughness compared with conventional dry grinding.

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