Grinding Wheel Surface Topography Research Articles

Research on the Grinding Performance of an Electroplated Coarse-Grained Diamond Grinding Wheel by Dressing

The coarse-grained electroplated diamond grinding wheels is increasingly favored in precision grinding of hard and brittle materials owing to its high material removal efficiency, high wear resistance and steady surface contour accuracy. However, how to determine whether the dressed grinding wheel surface topography can achieve the desired precision ground surface quality is still a huge challenge to this day. In this paper, a novel numerical simulation model, which was established basing on the statistical features of actual electroplated coarse-grained diamond grinding wheel and the kinetics of the grinding process, was proposed for theoretically and thoroughly studying the influence of the surface dressing depth of coarse-grained electroplated diamond grinding wheel on ground workpiece surface morphology. At first, the statistical features of actual electroplated coarse-grained diamond grinding wheel was acquired and a novel numerical grinding wheel surface model was established. Subsequently, a numerical ground workpiece surface simulation model was also developed. And then, the evolving mechanism of the grinding wheel surface topography with the dressed wheel surface abrasive grain protrusion height was theoretically studied by numerical simulation. Moreover, the influence of the wheel surface abrasive grain protrusion height on the ground surface roughness was thoroughly researched by means of theoretical model and experiments. The simulation and experiments results in this paper indicated that precision ground workpiece surface with nano-scale surface roughness can be acquired by grinding with a dressed grinding wheel with a certain abrasive grain protrusion height of 25% of the typical abrasive size. Comparing with the undressed grinding wheel (grinding wheel with original surface topography and not be dressed), the surface roughness Sa and Sq of the surface ground with a well-dressed wheel can achieving a significant decrease of 97.75–99.77% and 97.57–99.73%, respectively. Therefore, carefully dressing the electroplated coarse-grained diamond grinding wheel is of great significance for obtaining a precision ground workpiece surface quality.

Characterization of Ceramics Grinding Wheel Surface Topography in Creep Feed Grinding

Characterization of Ceramics Grinding Wheel Surface Topography in Creep Feed Grinding

A novel measurement method and application for grinding wheel surface topography based on shape from focus

The precision measurement of grinding wheel topography is of great significance for accurate evaluating grinding performance and improving the workpiece surface finish and grinding efficiency. In this paper, a reliable measurement method for grinding wheel topography based on shape from focus (SFF) is proposed, and in order to SSF can better adapt to the measurement of grinding wheel topography, a new sharpness function based on background subtraction and the gray level difference is constructed. The experimental results show that compared with traditional sharpness functions, the constructed sharpness function has higher unimodality (larger unimodal occupancy of total image points with 96.19%), higher contrast (smaller average occupancy of inflection point region in total image frames with 13.57%) and the shorter average operation time. On this basis, an improved Gaussian interpolation algorithm based on half-peak width is proposed to fit the sharpness evaluation curve calculated by sharpness function and capture the optimum focus position. The results show that the proposed method has better efficiency (shorter average operation time of each image points with 0.021 μs), smaller root-mean-squared-error and the sum of squares for errors, larger coefficient of determination than other curve fitting methods, which is more suitable for the proposed sharpness function to obtain the optimum focus position of image points. Finally, the three-dimensional reconstruction and measurement of grinding wheel topography are realized. The obtained results confirm the efficiency and precision of the above-mentioned method that could be a possible alternative to other methods used in grinding wheel topography measurement and then evaluating the grinding performance.

Numerical generation of grinding wheel surfaces based on time series method

Surface integrity has a significant influence on the functional behavior of engineering components. An effective grinding wheel topography model is the foundation to realize the controllable design and manufacturing of grinding workpiece surface integrity. In this study, a moving average model (MA) based on time series method was proposed to generate the grinding wheel surface topography. 3D grinding wheel topographies were measured by an LSM 700 laser scanning confocal microscope (CLSM). The Johnson transformation system was applied to generate the non-Gaussian sequence with predetermined statistical parameters. To address the convergence and memory requirement problems, the non-linear conjugate gradient method (NCGM) with an exact line search by the secant method was employed to solve the system of nonlinear equations. The results showed a good agreement between the measured and the generated surfaces in terms of the autocorrelation function (ACF) and statistical parameters was achieved. It is worth noting that the computing time of the model developed in this study is only determined by the autocorrelation lengths which are almost independent of the size of the grinding wheel. This technique could be more efficient when applied to grinding wheels with large size. Therefore, this method may serve as an effective way to solve the grinding wheel topography reconstruction problem.

Study on methods to optimize laser-sharpening quality, efficiency and topography

This paper aims to improve bond surface smoothness, sharpening quality and efficiency as well as control grain protrusion height. Systematic research was performed on pulsed fiber laser sharpening of a coarse-grained bronze-bonded diamond grinding wheel. The results show that bond surface smoothness is related to the laser spot overlap ratio Uc and the laser scan track overlap ratio Ul. In the range 10–70%, an increase in Uc and Ul improved the sharpened bond surface smoothness. Sharpening quality and efficiency are both related to laser power density Ip. In the range 2.115–6.344×107Wcm−2, an increase in Ip gradually improved sharpening efficiency, but the sharpening quality trend initially improved followed by a subsequent decline. The grain protrusion height is related to the laser scan cycles N. An excessively small N will result in an insufficient chip space such that the grinding wheel is likely blocked. Grains will likely fall off due to an insufficient holding force if N is excessively large. Compared with silicon carbide grinding wheel sharpening, a pulsed laser-sharpened grinding wheel exhibits less surface grain fall-off, better grain height uniformity, more chip space around the grain and superior grinding wheel surface topography.

Kinematics modeling and simulating of grinding surface topography considering machining parameters and vibration characteristics

Grinding is applied widely in manufacturing of high-precision component. And, pursuing the forming mechanism, together with predicting topography characteristics and roughness of the grinding surface, is becoming more and more important in improving the grinding quality. The grinding surface is formed by the interaction between the grinding wheel and the workpiece. And, its topography is influenced by the grain shape, grinding wheel surface topography, and machining parameters. In this paper, the study started from establishing the topography of wheel surface. And, according to grinding kinematics, the grain trajectory equations were established. By applying the statistical screening methods, the actual cutting depth was determined. Then, the grinding surface topography was formed by simulating. Considering the influence of vibration in actual grinding, the surface topography of the workpiece under forced vibration was studied. The study results showed that the influence of grinding speed was significant for grinding surface topography, mainly in the influence for amplitude and frequency. Finally, the grinding experiments were used to verify the results of the simulation. The obtained experimental results confirmed that the as-proposed method worked efficiently and rapidly in simulating the grinding surface topography and predicting the grinding surface roughness.

ステレオ画像による砥石作業面トポグラフィの機上3次元計測システム開発に関する研究

ステレオ画像による砥石作業面トポグラフィの機上3次元計測システム開発に関する研究

Modeling and simulation of useful fluid flow rate in grinding

This research established a mathematical model of the useful grinding fluid flow rate of a rough grinding wheel. The abrasive distribution matrix of the grinding wheel surface topography was programmed on the MATLAB software platform to obtain the grinding wheel porosity φ at different particle sizes. The grinding fluid flow field was simulated and studied by using the volume of fluid multiphase flow model of FLUENT. Results showed that given a certain circular velocity of the grinding wheel, a larger grinding fluid jet velocity resulted in greater useful grinding fluid flow. When the grinding fluid jet velocity was set, the useful grinding fluid flow increased with increasing circular velocity of the grinding wheel. With the increasing velocity of the grinding wheel, as affected by the airbond layer, the increasing rate of the useful grinding fluid flow decreased, and the flow likewise showed a tendency to decrease. With a certain grinding fluid jet velocity, the useful flow rate of the grinding fluid was positively proportional to the useful flow. When the grinding fluid jet velocity changed and grinding wheel velocity was set, the grinding fluid jet velocity increased as the useful flow rate decreased. When the grinding fluid jet velocity was equivalent to the grinding wheel velocity, the useful flow rate of the grinding fluid was positively proportional to the useful flow. When the minimum clearance of grinding zone h increased, the useful grinding fluid flow and useful flow rate likewise increased. When the grinding fluid jet velocity was equivalent to the grinding wheel velocity, a larger nozzle gap width increased the flow supply for the grinding fluid and the useful grinding fluid flow. However, the increase in the useful flow rate of the grinding fluid was significantly smaller than that of the nozzle flow. This condition decreased the useful flow rate of the grinding fluid.

Surface Topography of Mini-Size Diamond Wheel in Ultrasonic Assisted Grinding (UAG)

The objectives of this paper are to describe a quantitative evaluation of mini-size diamond grinding wheel surface topography in Ultrasonic Assisted Grinding (UAG) process and demonstrate the effects of topography on grinding characteristics. In this study, threedimensional (3D) analysis of the wheel working surface was observed using a Scanning Electron Microscope (SEM) with four electron probes (hereafter described as 3D-SEM) in an on-surface UAG process. These results indicated that a good wheel surface maintained in the UAG process is related to the number and the area of cutting edges. Additionally, the resulting topographic features of the grinding wheel surface are closely related to low grinding forces and allow easy manufacturing of a mirror workpiece surface.

A022 Surface Topography of Small Diameter Diamond Wheel in Ultrasonic Assisted Grinding

This paper aims to evaluate small diameter diamond grinding wheel surface topography in ultrasonic assisted grinding (UAG) process quantitatively and demonstrate the effect of the topography on grinding characteristics. In this study, a scanning electron microscope with four electron probes (3D-SEM) was used for 3D observations of the wheel working surface in on-surface UAG process. From these results, good wheel surface maintained in UAG process have been evaluated quantitatively by the number and the area of cutting edges. Additionally, these results are closely concerned to the low grinding forces and manufacturing of mirror workpiece surface easily, respectively.

Visualization of Grinding Wheel Surface Topography for Multiple Passes of Rotary Diamond Dresser

The grinding wheel surface topography after dressing is an indicator of the effectiveness of dressing operation and, thereby, the effectiveness of grinding as a whole. During dressing, the dresser travels the grinding wheel surface several times so that the dresser grits could hit all most all points on the circumference of the grinding wheel. But the same point should not be hit several times by the dressing grits. This study describes a method and tool for visualizing the grinding wheel surface topography for multiple passes of rotary diamond dresser. Using the proposed visualization method and tool, one can determine the effectiveness of certain dressing conditions beforehand. In addition, the visualization tool can be used for optimizing the design variables of a rotary diamond dresser.

Three Dimensional Analysis of a Grinding Wheel Surface with Image Processing

It is very important to measure a grinding wheel surface topography. Therefore a three dimensional measurement system of grinding wheel surface with image processing has been proposed. This system can evaluate a variety of the wheel surface topographies. For example, a histogram of the area or the shape of cutting edges and the distribution map of every shape of cutting edges were obtained. In this paper, a three dimensional model of the cutting edges and a correlation between the state of the wheel surface and grinding mark on the workpiece are reported and the effectiveness is evaluated through an experiment.

Simulation of Grinding Wheel with Random Three-Dimensional Abrasive and Microporous Bond

Be different from traditional simulation modeling method, in this paper, a random shape and distribution polyhedrons abrasive modeling method has been developed which simulation model is similar to the grinding wheel surface topography. Imitated the industrial process of abrasive production cutting, the characteristics of random distribution in the space and anisotropic of the abrasive particle shape on grinding wheel surface was also considered. A random geometry abrasive solid simulation model was developed which used random segmentation plane. Simulation modeling of grinding wheel in the past often overlooked component accounts for a large volume of wheel porous factors. Therefore, this article considered the random shape and position of the distribution of the abrasive and porous in grinding wheel bond of the simulation model, a random abrasive shape and porous distribute model was founded. It provides a meaningful model for the depth study of three-dimensional grinding simulation technology. Finally, grinding simulation results verified the reliability of the model.

Quantitive Evaluation and Modeling of Alumina Grinding Wheel Surface Topography

Grinding wheels are often characterized by the density and protrusion height of abrasive grains and cutting edges.Measurement and evaluation of grinding wheels contribute to the better understanding of grinding mechanism,which is also the necessary precondition of grinding optimization and simulation.White light interferometer are used to measure the surface topography of alumina grinding wheels.Three-dimensional surface characterization parameters from "Birmingham set" are employed to quantize the surface topography of grinding wheels,in items of grit density,shape and sharpness of grits.Mathematical models of the distribution of protrusion heights,are built based on statistical values of measured results.It is shown that the alumina abrasive grain can be simplified as a cone with tip radius.The tip radius is related with the abrasive grain size,while the cone angle is almost the same due to the same dressing and truing conditions.The result also shows that mathematical models of protrusion height of alumina grinding wheels accord with normal distribution.

Use of surface roughness measurements to improve the estimation of the heat partition in grinding

In grinding, the heat partition is used to estimate the percentage of energy entering the workpiece which makes it possible to estimate grinding temperatures. In this work, a correlation was observed between surface roughness and the heat partition when grinding 1018 steel with an 80 grit aluminum oxide wheel. This correlation was used to improve the usability of a popular heat partition model by making it easier to estimate the grain radius, which is an important parameter in this model. The grain radius is used to account for the grinding wheel surface topography and is virtually impossible to directly measure in practice. To validate the proposed model, infrared temperature measurements along with 3D finite element simulations were used to determine the heat partition for different dressing conditions and techniques. For the experimental conditions used in this research, the measurements and simulations confirmed that one can use surface roughness to estimate the grain radius. The average difference between the heat partition predicted using the proposed model and the conventional approach was 7.5%, while the resulting maximum grinding temperatures predicted using the proposed model agreed with infrared temperature measurements to within 5%.

Ordered diamond micro-arrays for ultra-precision grinding—An evaluation in Ti–6Al–4V

The surface topography of a conventional diamond grinding wheel can be characterised as having a perplexity of abrasive particles with random crystallographic orientations resulting in different heights of protrusion from the bond and inherent varying inter-particle spacing. The number and effectiveness of the abrasive particles during grinding depends on factors such as the abrasive concentration, the crystallographic shape and the extent of particle protrusion from the wheel’s surface. The consequence of this random layout inhibits the optimal performance of individual abrasives in the process of material removal, and where particles are clustered, chip flow is negatively affected. This paper reports on the evaluation of purpose designed precision diamond micro-arrays for the grinding a case-study material, Ti–6Al–4V and compares their performance against conventional diamond electroplated micro-cutting elements of D91 and D46 abrasive size in an imitated grinding setup. The precision diamond micro-arrays, produced from thick film CVD diamond utilising energy beam ablation offer an optimised layout of abrasive elements, each having a cutting width of 100 μm of identical crystallographic orientation, protrusion height and regular spacing to provide chip flow paths. In addition, the primary/secondary rake angles γ=−32°/+1° and clearance angle α=4.5° of each abrasive cutting element have been controlled in order to provide an enhanced cutting action. The precise layout of the abrasive cutting elements of the micro-arrays produced superior chip flow compared with the diamond electroplated grinding elements; this has been proven by in-depth scanning electron microscopy of the clogged workpiece material on the studied abrasive elements. The results show a 3.5 times improvement to surface finish and a 21.5 times improvement to flatness of the Ti–6Al–4V workpieces when ground with the proposed innovative diamond micro-arrays.

Recognition of diamond grains on surface of fine diamond grinding wheel

The accurate evaluation of grinding wheel surface topography, which is necessary for the investigation of the grinding principle, optimism, modeling, and simulation of a grinding process, significantly depends on the accurate recognition of abrasive grains from the measured wheel surface. A detailed analysis of the grain size distribution characteristics and grain profile wavelength of the fine diamond grinding wheel used for ultra-precision grinding is presented. The requirements of the spatial sampling interval and sampling area for instruments to measure the surface topography of a diamond grinding wheel are discussed. To recognize diamond grains, digital filtering is used to eliminate the high frequency disturbance from the measured 3D digital surface of the grinding wheel, the geometric features of diamond grains are then extracted from the filtered 3D digital surface, and a method based on the grain profile frequency characteristics, diamond grain curvature, and distance between two adjacent diamond grains is proposed. A 3D surface profiler based on scanning white light interferometry is used to measure the 3D surface topography of a #3000 mesh resin bonded diamond grinding wheel, and the diamond grains are then recognized from the 3D digital surface. The experimental result shows that the proposed method is reasonable and effective.

Analysis and Simulation of Grinding Wheel Surface Topography

The topography of the grinding wheel has a profound effect in analysis and predicting the finished surface roughness. In this paper, the statistical analysis is applied to establish a distribution function of the grain protrusion heights, and the 3-D simulating topography of grinding wheel will be identified. Through experiments, the generated grinding wheel topography is effective in predicting the finished surface roughness.

Measurement and evaluation of the surface topography of fine diamond grinding wheel

A 3D surface profiler based on scanning white light interferometry is introduced to measure the surface topography of a 3000 mesh diamond grinding wheel,and a large sampling area could be achieved by its image stitching capability without compromising lateral or vertical resolution.Fourier analysis is performed to identify the frequency structure of the wheel's surface topography,and then the characteristics of diamond grains are extracted by digital filtering.The protrusion height distribution of diamond grains,the static effective grain density and the distribution of inter-grain spacing of the grinding wheel are derived.The study shows that the grain protrusion height obeys an approximate normal distribution,the static effective grain density is much lower than the theoretical grain density, and only a small number of diamond grains are effective in grinding process with fine diamond grinding wheel.

613 砥石作業面トポグラフィの機上測定法に関する研究(OS11-3 加工計測・加工機械,オーガナイズドセッション:11 加工技術の高度化)

613 砥石作業面トポグラフィの機上測定法に関する研究(OS11-3 加工計測・加工機械,オーガナイズドセッション:11 加工技術の高度化)