Calculation of the Contact Stiffness of Grinding Wheel

2011 ◽  
Vol 325 ◽  
pp. 54-59 ◽  
Author(s):  
Takazo Yamada ◽  
Michael N. Morgan ◽  
Hwa Soo Lee ◽  
Kohichi Miura
Keyword(s):  
Stationary State ◽  
Contact Stiffness ◽  
Grinding Wheel ◽  
Abrasive Grains ◽  
Calculating Method ◽  
Abrasive Grain

It is considered that the contact stiffness between the grinding wheel and the workpiece depends on the number of the abrasive grains in contact with the workpiece and the support stiffness of a single abrasive grain. In this paper, the calculating method of the theoritical contact stiffness of grinding wheel in grinding operation was proposed. Comparing calculated results of the contact stiffness in grinding operation with measured it in the stationary state, the contact stiffness of the grinding wheel in grinding operation was investigated.

Contact Stiffness of Grinding Wheels due to the Difference of Table Feed Rate

2009 ◽  
Vol 76-78 ◽  
pp. 137-142 ◽  
Author(s):  
Takazo Yamada ◽  
Hwa Soo Lee ◽  
Kohichi Miura
Keyword(s):  
Stationary State ◽  
Feed Rate ◽  
Contact Stiffness ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Abrasive Grain ◽  
Residual Stock ◽  
The Difference ◽  
Stock Removal

Usually, the contact stiffness between a grinding wheel and a workpiece has been measured in a stationary state. So, in this study, the contact stiffness under the grinding operation is measured under different table feed rate of the workpiece. From this result, it is known that, while the contact stiffness in the stationary state increases with the increase of the contact force, the contact stiffness under the grinding operation decreases with the increase of the normal grinding force relating the table feed rate. In this paper, since the number of contacting abrasive grain with workpiece is constant irrespective of the table feed rate, and the residual stock removal of workpiece is varied by the table feed rate, it is clarified that the contact stiffness under the grinding operation differs from the contact stiffness measured by the stationary state.

Mathematical Model of the Grinding Force With Account for Blunting of Abrasive Grains of the Grinding Wheel

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Dmitrii V. Ardashev ◽  
Aleksandr A. Dyakonov
Keyword(s):  
Forecast Model ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Force Model ◽  
Cyclic Loads ◽  
Workpiece Material ◽  
Stochastic Nature ◽  
Abrasive Grains ◽  
Working Surface ◽  
Abrasive Grain

The paper offers a simulation model of the grinding force with account for the current condition of the grinding wheel's working surface—the value of the abrasive grain blunting area. The model of blunting area takes into account various wear mechanisms for abrasive grains: the mechanical wear is realized on the provisions of the kinetic theory of the strength of a solid subjected to cyclic loads, and the physicochemical wear is based on the intensity of interaction between the abrasive and the treated material at grinding temperatures. The offered model of the grinding force takes into account the unsteady stochastic nature of the interaction between abrasive grains of the grinding wheel and the working surface and the intensity of workpiece material deformation resistance. The model is multifactorial and complex and can be realized by supercomputer modeling. The numerical implementation of the model was performed with application of supercomputer devices engaging parallel calculations. The performed experiments on measurement of the grinding force during circular grinding have shown a 10% convergence with the calculated values. The developed grinding force model can be used as a forecast model to determine the operational functionality of grinding wheel when used in varying technological conditions.

A Fundamental Study on the Digital Recognition of Grinding Wheel

2007 ◽  
Vol 359-360 ◽  
pp. 504-508
Author(s):  
Jun Feng Gong ◽  
Xi Peng Xu
Keyword(s):  
Stereo Vision ◽  
Three Dimensional ◽  
Optical Microscope ◽  
Grinding Wheel ◽  
Quick Method ◽  
Fundamental Study ◽  
Depth From Focus ◽  
Abrasive Grains ◽  
Abrasive Grain ◽  
Wheel Topography

In this paper, the 3D morphology of a grinding wheel was modeled by the depth from focus. Firstly, the picture information of different heights was extracted by the up-down moving of the microscope. The operator Laplacian was adopted to distinguish the distinct and fuzzy areas in a picture. Then, the distinct image and height information was obtained. The information of height was distorted due to the occurrence of noise. In order to reconstruct 3D surface, a method based on Min/Max curvature flow was developed to remove noises. In the end, an abrasive grain in the image of a grinding wheel was segmented by the Mumford-Shah model. The results could be further developed to evaluate the worn status of grinding wheels. Introduction The examination of the wear of abrasive grain in the grinding wheel is very important for evaluation of performance of diamond grinding wheel. The three-dimensional (3D) reconstruction of grinding wheel topography can provide more information about wear of abrasive grains than common ways such as observation by optical microscope. Nowadays, there have been many techniques to be considered to obtain 3D data, for example, profilometry, the scanning electron microscope (SEM), the scanning laser microscope (SLM), stereo vision and so on. SEM is a powerful measuring tool, but the time needed for sample coating process and chamber air pumping is considerable. SLM is promising tool for 3D shape modeling, but still expensive for most of users. Stereo vision is simple and quick method to obtain the height information, but only the height of points which match in two corresponding images could been obtained. In this paper, a new method based on depth from focus (DFF) [1] is presented for 3D modeling. Compared with SEM and SLM, it is easy and not very expensive equipments are needed. Meanwhile, it can provide more real 3D model than stereo vision method. In order to measure the abrasive grains, a segmentation Algorithms based on Mumford-Shah model [4] is introduced to divide the grains from image of grinding wheel.

Prediction of Blunting Area of Abrasive Grains on a Grinding Wheel

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Aleksandr A. Dyakonov ◽  
Dmitrii V. Ardashev
Keyword(s):  
Cutting Speed ◽  
Mathematic Model ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Wheel Wear ◽  
Abrasive Wheel ◽  
Abrasive Grains ◽  
Abrasive Grain ◽  
Mass Transfer Theory ◽  
First Time

The article presents the results of calculating the blunting area of abrasive grains of grinding wheels, determined in accordance with the previously developed model. The mathematic model of the size of the blunting area of an abrasive grain considers the main mechanisms of its wear—mechanical and physicochemical. These mechanisms are taken into account in the model. For the first time, the kinetic theory of strength was used for determining the mechanical wear of abrasive grain. The mass transfer theory was used to study the physicochemical wear: coefficients of chemical affinity with the abrasive material are experimentally defined for the assortment of workpiece materials. The developed mathematic model is a multiple-factor one and this will allow to predict the size of wear of the abrasive wheel for different technological conditions. Also, the article presents the experimental method for determining the blunting area of abrasive grains of grinding wheels, which allows making a direct measurement of wear parameters of grinding wheels. The main parameter of grinding wheel wear is the length of the blunting area of the grain, which was measured out in the direction of the cutting speed vector. The grinding wheels of different graininess were studied—F60 and F46. The grinding wheel working surface was studied by numerical photos and microscope. The results of these experiments have confirmed the adequacy of the design model.

Observation of Abrasive Grains Behavior in Contact Area of Grinding Wheel and Comparison with Grinding Wheel Model

2008 ◽  
Vol 389-390 ◽  
pp. 48-54
Author(s):  
Taisei Yamada ◽  
Hwa Soo Lee
Keyword(s):  
Contact Area ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Grinding Forces ◽  
Elastic Deformations ◽  
Contact Areas ◽  
Abrasive Grains ◽  
Abrasive Grain ◽  
Wheel Model

In contact areas between grinding wheels and workpieces, elastic deformations of grinding wheel take place due to the act of grinding forces. Since grinding wheels consist of abrasive grains and bonds, it may be regarded that the elastic deformations of grinding wheels in contact areas depend on movements of each abrasive grain. However, plural grains are connected each other complicatedly, and then it is difficult to observe each grain behavior. This study aims to directly observe the behaviors of grains in contact areas with workpieces. A small loading apparatus for grinding wheel is newly developed. Inserting a loaded wheel with this apparatus into SEM, grains behaviors in contact area are directly observed. Furthermore, grains behaviors under loaded condition are analyzed with a wheel model developed previously and observed results are compared with analyzed results.

Improvement of Surface Roughness with Micro-Axial Vibration of Spindle by Pressure Pulsation of Grinding Fluid Supplied through inside of Wheel

2016 ◽  
Vol 1136 ◽  
pp. 673-677
Author(s):  
Kosaku Nomura ◽  
Naoya Takeuchi ◽  
Atsushi Kusakabe ◽  
Masahisa Chino ◽  
Hiroyuki Sasahara
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Pressure Pulsation ◽  
Grinding Wheel ◽  
Axial Vibration ◽  
Machined Surface ◽  
Plunger Pump ◽  
Abrasive Grains ◽  
Abrasive Grain ◽  
Grinding Fluid

In grinding, the moving trajectories of abrasive grains are almost straight to the motion of the rotation and feed of the grinding wheel, so that grinding marks are formed continuously. As a result, surface roughness is dependent on grain size and organization of the grinding wheel. If the trajectory of the abrasive grain is wavy, the peak lines of the grinding marks will be partially removed by following the abrasive grain. This improves surface roughness. The objective of this study is to develop a mechanism to give axial vibration to the grinding wheel by the pulsation of the plunger pump, and thus to improve the surface roughness of the machined surface.

Abrasive Grain Efficiency and Surface Roughness in Machining Magnesium Alloys by Newly Developed Cup-Type Diamond-Grinding-Wheels

2009 ◽  
Vol 620-622 ◽  
pp. 769-772
Author(s):  
Tien Dong Nguyen ◽  
Koji Matsumaru ◽  
Masakazu Takatsu ◽  
Kozo Ishizaki
Keyword(s):  
Surface Roughness ◽  
Magnesium Alloys ◽  
Unit Length ◽  
Grinding Wheel ◽  
Light Metals ◽  
Grinding Wheels ◽  
Wheel Surface ◽  
Abrasive Grains ◽  
Diamond Grinding ◽  
Abrasive Grain

New cup-type diamond-grinding-wheels with hexagonal pattern have been developed. Grinding stone ratio, R is defined as the ratio between the hexagonal edge area containing abrasive grains and the total area of the wheel surface. In the present work, four kinds of hexagonal grinding wheels with different R (13 %, 19 %, 25 % and 36 %) and a conventional wheel (R: 100 %) were used to grind a light metals, which was represented by magnesium alloy AZ31B. Efficiency of abrasive grains and ground surface for machining a light metals were evaluated by calculating the number of abrasive grains which pass through a unit length of a sample surface for each grinding pass, Ng. The results show that surface roughness becomes smaller, i. e., smoother surfaces as Ng increases. Surfaces ground by the conventional wheel are rougher than those by using newly developed hexagonal grinding-wheels in spite of the larger Ng for the conventional wheel. Surface roughness data forms one curve in roughness vs. Ng graph for all hexagonal wheels, and forms another curve for the conventional grinding-wheel. The difference of two curves indicates that the number of effective working abrasive grains in hexagonal wheels is about 5 times higher than that of the conventional wheel. The similar results were obtained for machining sapphire according to our previous work. Hexagonal wheels show higher abrasive grain efficiency for machining not only hard-to-machine ceramics but also light metals such as magnesium alloys than conventional wheels.

Methodology for Evaluation of Treated Steels and Alloys in Abrasive Processing

2021 ◽  
Vol 410 ◽  
pp. 262-268
Author(s):  
Vyacheslav M. Shumyacher ◽  
Sergey A. Kryukov ◽  
Natal'ya V. Baidakova
Keyword(s):  
Physical And Mechanical Properties ◽  
Metals And Alloys ◽  
Grinding Wheel ◽  
Measuring Instruments ◽  
Abrasive Machining ◽  
Machining Performance ◽  
Abrasive Grains ◽  
Abrasive Tools ◽  
Composition Structure ◽  
Grinding Operations

One of the critical physical and mechanical properties of metals and alloys is the suitability for abrasive machining. Machining by abrasive tools is the final operation that sets the desired macro-geometry parameters of processed blanks and microgeometry parameters of processed surfaces such as roughness and length of a bearing surface. Abrasive machining determines the most important physical and mechanical parameters of a blank surface layer, i.e. stresses, phase composition, structure. Machinability by abrasive tools depends on the machining performance affected both by the blank material properties and various processing factors. In our previous studies, we proved that during abrasive machining the metal microvolume affected by abrasive grains accumulates energy. This energy is used for metal dispersion and is converted into heat. According to the theoretical studies described herein, one may note the absence of a reliable and scientifically valid method as well as measuring instruments to determine the machinability of metals and alloys by abrasive tools. For this reason, we suggested a method simulating the effect the multiple abrasive grains produce in a grinding wheel, and enabling us to identify machinability of metals and alloys, select the most efficient abrasive materials for machining of the same, and form the basis for development of effective grinding operations.

scholarly journals The enhancement of cutting capacity of a grinding wheel when processing ductile steel blank parts by ultrasonic activation

2021 ◽  
pp. 55-62
Author(s):  
A. V. Khazov ◽  
◽  
A. N. Unyanin ◽  
Keyword(s):  
Numerical Simulation ◽  
Grinding Wheel ◽  
Ultrasonic Vibrations ◽  
Ultrasonic Activation ◽  
Workpiece Material ◽  
Steel Blank ◽  
Micro Cutting ◽  
Abrasive Grains ◽  
Junction Points ◽  
Cutting Capacity

The study aimed to identify the relations between the sticking intensity and ultrasonic vibrations (UV) used for processing and evaluate the wheels’ performance when grinding ductile materials blank parts. The authors carried out the numerical simulation of local temperatures and the 3H3M3F steel workpiece temperature when grinding by ultrasonic activation. The study determined that the application of ultrasonic vibrations with the amplitude of 3 µm causes the decrease in local temperatures by 13…40 %, and in blank part temperature – up to 20 %. The calculation identified that the activation of ultrasonic vibrations with the amplitude of 3 µm causes the decrease in the glazing coefficient by 33 % for cutting grain and by 7 % for deforming grain. When increasing the longitudinal feed rate or the grinding depth, the glazing coefficient increases to a lesser degree when using the ultrasonic vibration than in the case without ultrasonic activation. The authors carried out the numerical simulation of local temperatures when scratching the 3H3M3F steel specimens by single abrasive grains with ultrasonic activation. The sticking deformation and the stresses resulted from this deformation and affecting the junction points of sticking with grains with and without ultrasonic vibrations application are calculated. The experimental research included the micro-cutting of specimens with single abrasive grains. The experiments identified that the abrasive grains wear out and glaze to a lesser degree when micro-cutting a workpiece with ultrasonic vibrations activation. The lowering of the intensity of sticking of the workpiece material particles to the abrasive grains due to the adhesion causes the decrease in the glazing coefficient when using ultrasonic activation. The study considered the possibility to enhance the efficiency of flat grinding through the use of the energy of ultrasonic vibrations applied to a blank part in the direction with the grinding wheel axis. A workpiece fixed in the device between the vibration transducer and the support is one of the components of a vibration system. The authors performed the experiment when grinding 3H3M3F and 12H18N10T steel workpieces with the wheel face. When grinding with ultrasonic vibrations, the grinding coefficient increases up to 70 %, and the redress life increases twice or thrice.

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