Estimation Method of Grain-Height Distribution Based on the Working Surface Profile of Grinding Wheels

2009 ◽  
Vol 76-78 ◽  
pp. 143-148 ◽  
Author(s):  
Haruhisa Sakamoto ◽  
Shinji Shimizu ◽  
Shinichi Kashiwabara ◽  
Hitoshi Tsubakiyama

To manage and control grinding process theoretically, the cutting-edge density should be quantified. In this study, the estimation method of the grain-height distribution, which is necessary to quantify the cutting-edge density, has been examined. From the results of simulation by modeling the grain distribution of a grinding wheel, the close correlation has been confirmed between the grain-height distribution and the peak-height distribution of the working surface profile. Based on this, the grain-height distribution can be estimated from the peak-height distribution by narrowing the width accompanied maintaining the total frequency. Since the estimated grain-height distribution agreed well to the distribution determined from the measured 3D-topography, the validity of the method has been confirmed.

2011 ◽  
Vol 325 ◽  
pp. 60-65
Author(s):  
Haruhisa Sakamoto ◽  
Kyoko Nakamura ◽  
Yoshinori Sasaki ◽  
Shinji Shimizu

In this study, the determination method of the number of the effective cutting-edges had been proposed based on the measurements of working surface topography and the grinding force. Furthermore, its validity is made clear based on the topographical analysis of the ground surface roughness of pure copper, which is excellent in transcribing the working surface. From the results, the following are found out: The ground surface topography contains the periodical component, which is originated in the grinding and dressing conditions, on the fractal noise component. The cutting traces by each cutting-edge can be countable from the ground surface profile, and then, the number of the effective cutting-edges is identified at one line within the working surface. On the other hand, the number of the effective cutting-edges also can be identified based on the working surface, but, this method requires the determination of the typical grain shape. From the experiment, it is confirmed that the grain shape should be almost spherical for making the numbers of the effective cutting-edge identified from the working and ground surfaces equal.


2009 ◽  
Vol 76-78 ◽  
pp. 149-154 ◽  
Author(s):  
Haruhisa Sakamoto ◽  
Hitoshi Tsubakiyama ◽  
Shinji Shimizu ◽  
Shinichi Kashiwabara

In this study, the quantification method of the cutting-edge density is proposed because of its close relation to the grinding mechanism. The cutting-edge density depends upon not only the grain distribution but also the thickness of effective cutting-edge layer. Therefore, the quantification of the cutting-edge density requires measuring not only the profile but also the grinding force. The thickness of effective cutting-edge layer can be determined based on the grain distribution, the grinding force and the stiffness of a grinding wheel. From applied result of the proposed method for the actual grinding process, the cutting-edge density and the effective cutting-edges layer is determined appropriately corresponding to the change in the working surface condition.


Author(s):  
Abdalslam Darafon ◽  
Andrew Warkentin ◽  
Robert Bauer

This paper presents a new empirical model of the dressing process in grinding which is then incorporated into a 3D metal removal computer simulator to numerically predict the ground surface of a workpiece as well as the dressed surface of the grinding wheel. The proposed model superimposes a ductile cutting dressing model with a grain fracture model to numerically generate the resulting grinding wheel topography and workpiece surface. Grinding experiments were carried out using “fine”, “medium” and “coarse” dressing conditions to validate both the predicted wheel topography as well as the workpiece surface finish. For the grinding conditions used in this research, it was observed that the proposed dressing model is able to accurately predict the resulting workpiece surface finish for all dressing conditions tested. Furthermore, similar trends were observed between the predicted and experimentally-measured grinding wheel topographies when plotting the cutting edge density, average cutting edge width and average cutting edge spacing as a function of depth for all dressing conditions tested.


2015 ◽  
Vol 756 ◽  
pp. 15-18
Author(s):  
Dmitrii V. Ardashev

During the grinding process the main role is played by the vibrating phenomena caused by primary imbalance of a wheel, features of its structure, and also the existence of a component arising in the general scale of vibrations and caused by the change of the structure of a working surface of a grinding wheel, wear of its working abrasive grains during the process. Intensity and amount of wear of the grinding wheel depends on conditions of grinding operation – kind of grinding, processed material, etc. In turn, the existence of close correlation connection between parameters of vibrations and modes of grinding allows to assume, that vibrating processes possess sufficient information and can form the basis for an assessment and forecast the perfection factor of a grinding wheel directly in operating conditions.


2015 ◽  
Vol 809-810 ◽  
pp. 81-86
Author(s):  
Alexander Mikhailov ◽  
Anatoly Baykov ◽  
Ilya Navka

Formation of the ground surface is the result of the interaction of the cutting elements of the diamond tool with the material being processed, so the nature of the working surface geometry of the grinding wheel (WSW) has principal value on processed surface quality. One of the main parameters that characterize the geometry of the WSW is the law of the grain distribution vertex in height. However, statistical models do not reflect the real picture of the tool interaction with the material being processed in the modelling process of grinding tool on the elastic ligament used for final operations. In the process of contact with the material being processed each diamond grain is moved with an adjacent block ligament, changing the position of the cutting vertex relative to both the midrange cords level and the other grains vertexes. As a result the nature of the grain vertexes distribution changes and the conditions of interaction with the material being processed change too. Studies have shown that the density distribution in height of diamond grains elastic grinding tool vertexes in a static state can be described by different distribution laws. For practical use in the calculation of the processed surface roughness and processing capacity is sufficient to approximate the distribution in height only the most protruding grains. In the area of contact with the processed material the distribution density of the grains elastic tool in height significantly differs from the static characteristics and is defined by the elasticity degree of the grinding tool ligament and machinability index of the workpiece material. The obtained results can serve as initial data for the calculation of the processed surface roughness.


2010 ◽  
Vol 126-128 ◽  
pp. 1001-1006
Author(s):  
Haruhisa Sakamoto ◽  
Shinji Shimizu

The grinding should be improved to be the skill-free process executed based on the quantified criteria. In this study, the evaluation methods are applied to evaluate the dressing process to clarify how the dressing changes the cutting-edge distribution. From the results, the following facts have been clarified: There is the critical value of the depth of cut for suppressing the release of grain. The spark-out in dressing releases grains damaged by collision with dresser, and then, it also increases the cutting-edge density.


2008 ◽  
Vol 26 (8) ◽  
pp. 2069-2080 ◽  
Author(s):  
N. B. Gudadze ◽  
G. G. Didebulidze ◽  
L. N. Lomidze ◽  
G. Sh. Javakhishvili ◽  
M. A. Marsagishvili ◽  
...  

Abstract. Long-term observations of total nightglow intensity of the atomic oxygen red 630.0 nm line at Abastumani (41.75° N, 42.82° E) in 1957–1993 and measurements of the ionosphere F2 layer parameters from the Tbilisi ionosphere station (41.65° N, 44.75° E) in 1963–1986 have been analyzed. It is shown that a decrease in the long-term trend of the mean annual red 630.0 nm line intensity from the pre-midnight value (+0.770±1.045 R/year) to its minimum negative value (−1.080±0.670 R/year) at the midnight/after midnight is a possible result of the observed lowering of the peak height of the ionosphere F2 layer electron density hmF2 (−0.455±0.343 km/year). A theoretical simulation is carried out using a simple Chapman-type layer (damping in time) for the height distribution of the F2 layer electron density. The estimated values of the lowering in the hmF2, the increase in the red line intensity at pre-midnight and its decrease at midnight/after midnight are close to their observational ones, when a negative trend in the total neutral density of the upper atmosphere and an increase in the mean northward wind (or its possible consequence – a decrease in the southward one) are assumed.


Author(s):  
Ashwani Pratap ◽  
Karali Patra

Abstract This work presents an analytical cutting force modeling for micro-slot grinding. Contribution of the work lies in the consideration of both primary and secondary tool surface interactions with the work surface as compared to the previous works where only primary tool surface interaction was considered during cutting force modeling. Tool secondary surface interaction with workpiece is divided into two parts: cutting/ ploughing by abrasive grits present in exterior margin of the secondary tool surface and sliding/adhesion by abrasive grits in the inner margins of the secondary tool surface. Orthogonal cutting force model and indentation based fracture model is considered for cutting by both the abrasives of primary tool surface and the abrasives of exterior margin on the secondary surface. Asperity level sliding and adhesion model is adopted to solve the interaction between the workpiece and the interior margin abrasives of secondary tool surface. Experimental measurement of polycrystalline diamond tool surface topography is carried out and surface data is processed with image processing tools to determine the tool surface statistics viz., cutting edge density, grit height distribution and abrasive grit geometrical measures. Micro-slot grinding experiments are carried out on BK7 glass at varying feed rate and axial depths of cut to validate the simulated cutting forces. Simulated cutting forces considering both primary and secondary tool surface interactions are found to be much closer to the experimental cutting forces as compared to the simulated cutting forces considering only primary tool surface interaction.


2014 ◽  
Vol 1017 ◽  
pp. 592-597 ◽  
Author(s):  
Akihiko Kubo ◽  
A.M.M. Sharif Ullah ◽  
Jun’ichi Tamaki

The surface of a grinding wheel dressed by a diamond rotary dresser was generated by computer-aided simulation for the case of multipass dressing on the assumption that the grinding wheel is a homogeneous solid body and the dressing trajectories of the diamond grits are perfectly copied on the grinding wheel surface. The dressing process was visualized as a contour map of the dressed surface profile and the effects of the dressing strategy, i.e., down-cut dressing or up-cut dressing, on the grinding wheel removal process were investigated. It was found that the diamond grits remain the residual depth of cut on the surface of the grinding wheel, resulting in an actual depth of cut larger than that given by the rotary dresser.


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