Grinding Parameters Research Articles

Review on Research and Development of Abrasive Scratching of Hard Brittle Materials and Its Underlying Mechanisms

Hard brittle materials such as ceramics and crystals are commonly utilized in various industries, including information technology, mechanical engineering, and semiconductors. These materials, known for their high brittleness and hardness but low fracture toughness, pose challenges in efficient and high-quality machining. Current abrasive machining techniques involve rough grinding, fine grinding, and polishing processes, with the latter being the most time-consuming and accounting for over half of the total machining time. Improving processing parameters in rough and fine grinding can increase machining efficiency, reduce surface and subsurface damage, and improve workpiece quality, ultimately reducing the polishing time. This paper explores the abrasive scratching of hard brittle materials, examining the nucleation and propagation of cracks causing surface and subsurface damage, and the underlying mechanisms. The research provides suggestions for enhancing abrasive machining efficiency and ensuring the surface quality of hard brittle materials.

Grinding Force and Surface Formation Mechanisms of 17CrNi2MoVNb Alloy When Grinding with CBN and Alumina Wheels

The 17CrNi2MoVNb alloy is widely used for manufacturing heavy-duty gears in vehicles' transmission systems, where grinding is a significant process affecting gears' working performance and service life. This work comprehensively analyzed the grinding force, surface morphology, and surface roughness when grinding 17CrNi2MoVNb alloy using alumina and CBN grinding wheels. Results showed that the maximum normal grinding force from the CBN wheel was only ~67% of the one from the alumina wheel. Due to the small size and limited cutting depth of CBN grains, the grinding force increased by about 20% when the grinding depth increased from 0.02 to 0.03 mm for CBN grinding wheels. Surface defects, including cavities and material tearing, were mainly found on the ground surface when using an alumina grinding wheel. The surface roughness Ra recorded from the CBN grinding wheel mainly ranged from 0.263 to 0.410 μm, accounting for less than 40% of the one from the alumina grinding wheel. The information from this work could provide benchmark data and references for optimizing grinding tools and parameters when manufacturing gears in the vehicle industry.

Burr formation mechanism and morphological transformation critical conditions in grinding of nickel-based superalloy honeycomb cores

Nickel-based Superalloy Honeycomb (NBSH) is widely used in aerospace field due to the high temperature resistance, high specific strength and light weight. However, the NBSH is extremely prone to form burrs during processing. The unreasonable burr morphology causes insufficient welding strength or false welding between NBSH and skin, resulting in premature failure of the parts. Hence, the burr formation mechanism and morphological transformation critical conditions in grinding NBSH were investigated based on finite element method (FEM) and experiments. Furthermore, the orthogonal experiments were carried out to investigate the effects of grinding parameters on burr and obtain the suitable parameter intervals to restrain the flash burr formation. The results indicate that due to the absence of supporting material, the extruded material of edge transforms into the Fourth Deformation Zone (FDZ). The FDZ rotates a certain angle due to the extrusion of abrasive particle, which leads to the fact that the FDZ cannot be removed and remains on the honeycomb wall, thus forming micro burr. If the material removal per unit time is large, the chip is not removed from FDZ. The parts that should have been chips are bonded with micro burr to form a flash burr. To restrain the flash burr formation, the suitable intervals of grinding depth, grinding speed and feed speed are 5–15 μm, 60–70 m/min and 500–1000 mm/min, respectively.

Static numerical simulation of radial deformation of ultra-thin dicing blade

Grinding with dicing blade is an important method to cut or slot electronic and optical devices. The deformation of grinding tools will definitely affect the processing of workpiece. However, this effect has been disregarded during processing. In order to improve the machining accuracy in the precision grinding method, this deformation is worth considering. In this research, the grinding state of the ultra-thin dicing blade was simplified as a static problem. The force model of the ultra-thin dicing blade during grinding was established, which centrifugal force was adopted in the whole blade and triangular distribution grinding forces were adopted in the grinding area. The radial deformation of the ultra-thin dicing blade was determined by finite element simulation, and the influence of grinding parameters on its radial deformation was analyzed. The simulation results showed that the grinding area of the ultra-thin dicing blade occurred radial expansion deformation at high rotational speed (more than 8000 rpm), and the value could reach 1.75 μm (rotational speed at 23,000 rpm, feed speed at 600 mm/min, and grinding depth at 0.12 mm). The deformation increased in a form of power function with the increase of rotational speed, and decreased linearly with the increase of feed speed and grinding depth. This work can provide reference data for deformation compensation, which is helpful to improve the dimensional accuracy of grinding groove.

Investigation on Surface Integrity of Nodular Cast Iron QT700-2 in Shape Adaptive Grinding

Nodular cast iron QT700-2 is extensively used in automobile engine crankshaft parts due to its prime mechanical properties. The journal of a crankshaft is a curved surface, and traditional wheel grinding easily causes grinding burn and surface and subsurface damage. Shape adaptive grinding (SAG) is a flexible grinding technology, which has the advantages of low grinding force and temperature, and good grinding quality. It is suitable for machining curved surface parts with complex shapes. Therefore, the SAG surface integrity of nodular cast iron QT700-2 was experimentally investigated. The influence of grinding parameters on grinding force, material removal rate, grinding temperature, and surface integrity was studied, and the machining performance of SAG tools was evaluated. It was concluded that the grain size in SAG is the most important factor affecting the grinding force, material removal rate, and surface roughness; the influence of SAG grinding is very weak, mainly removing the workpiece material. Then, the influence law of SAG technology on the surface integrity of nodular cast iron QT700-2 was summarized, and the optimal grinding parameters were obtained, providing a reference for the curved surface grinding of nodular cast iron QT700-2 in the future.

Study on Grinding Force of Two-Dimensional Ultrasonic Vibration Grinding 2.5D-C/SiC Composite Material

The grinding force is an important index during the grinding process, which affects the surface quality and other aspects after machining. However, the research on the grinding force of ceramic matrix composites assisted by two-dimensional ultrasonic vibration-assisted grinding is very weak. In this paper, the impact of the relationship between the critical cutting depth and the maximum undeformed chip thickness on the removal mode of ceramic matrix composites was analyzed. On this basis, the grinding force model of two-dimensional ultrasonic vibration-assisted grinding were developed for ductile removal and brittle removal, respectively. Finally, the correctness of the model was verified, and the impact of grinding parameters on the grinding force was analyzed. The experimental results show that compared with the conventional grinding force, the two-dimensional ultrasonic vibration assisted grinding force decreases obviously. When the feed rate and grinding depth increase, the grinding force increases. When the grinding velocity and ultrasonic amplitude increase, the grinding force decreases. Compared with the experimental value, the average relative error of normal grinding force is 8.49%, and the average relative error of tangential grinding force is 13.59%. The experimental and theoretical values of the grinding force have a good fitting relationship.

Surface Morphology and Subsurface Microstructure Evolution When Form Grinding 20Cr2Ni4A Alloys.

20Cr2Ni4A alloy is widely used in the manufacturing of heavy-duty gears, although limited information about its machinability during the form-grinding process has been reported. In this work, form-grinding trials on transmission gears of 20Cr2Ni4A alloy under various parameters were conducted. Surface morphology of the gear tooth, surface roughness distribution and microstructure evolution of the machined surface layer were comprehensively studied, and the influence of grinding parameters on grinding performance was investigated. The formation mechanisms of surface/subsurface defects during the form-grinding process, including plastic flow, deep grooves, successive crushing zone, adhesive chips and cavities, were analyzed. Results showed that the change in contact conditions between the grinding wheel and tooth surface led to the decrease in the surface roughness from tooth tip to root. Mechanical force and grinding heat promoted the deformation and refinement of the microstructure within the machined surface layer. With the increase in cutting depth and feed speed, the deformation ratio of the microstructure increased, which was also consistent with the variation trend in the form-grinding temperature.

Surface grinding responses optimization with a promising eco-friendly cutting fluid

Lubrication and cooling are very important to safeguard grinding quality, in terms of surface integrity, surface texture, and accuracy of dimensions of the workpiece, because of the friction and the heat generation associated with the surface grinding process. So, cutting fluids are used to achieve this. Due to the ecological and health hazards of cutting fluids formulated from mineral oil and chemicals, the focus is on the use of bio-oil-based cutting fluids. Owing to the desirable properties of cashew nut shell liquid, it is attempted as a cutting fluid to optimize the surface roughness and cooling in surface grinding of EN8 material. The study deals with the analysis of the grinding parameters such as the type of cutting fluid, grinding wheel speed, grinding wheel grade, depth of cut, and workpiece speed as influential factors on the responses i. e. surface finish and grinding temperature. The performance of cashew nut shell liquid is compared to traditional synthetic cutting fluid using Taguchi’s 25 experimental design and L16 Orthogonal Array. A prediction model is proposed for both surface roughness and grinding temperature to get the optimum grinding parameters. The accuracy of the models is tested by conducting validation and confirmation experiments. The experimental results confirm well with those predicted and show that there is an improvement in the surface grinding responses when cashew nut shell liquid is used as a cutting fluid.

Статистический анализ особенностей динамики развития теории и практики совершенствования измельчительно-режущего оборудования

The article solves the problem of assessing the preference and sequence of stages of application of priority methods for improving grinding and cutting equipment depending on the quantitative dynamics for the appearance of theoretical works characterized by analytical mechanisms of description, on the one hand, and interspersed with publications of heuristic works using the theory of solving inventive tasks, on the other. We statistically studied the change in publication activity in terms of publishing scientific papers on improving the grinding and cutting technology and the intensity of heuristic inventive activity in this information field. As a result, the provisions are substantiated and stated, from which it logically follows the need for timely activation of the processes of improving screw grinding equipment by analytical or heuristic methods, with a focus on the cyclicity and phasing of the productivity of these methods. For this purpose, a generalized structural design and technological scheme of the grinding-cutting system has been developed. The main features, geometric parameters and physical and mechanical characteristics of the components are determined. It is shown that the task of identifying priority analytical or heuristic step-by-step methods of assessing directions for improving the parameters of grinding and cutting equipment is one of the most important and logically complete system elements in the theory and practice of optimal synthesis of screw grinders. It seems that the proposed concept is applicable to any branch of technology. For auger grinding and cutting equipment, on the basis of the above methodology, another priority task was formulated, which consists in an analytical description of the distribution law of the blade sharpening angle along the length of the cutting edge, taking into account the phenomenon of its kinematic transformation.

Experimental study of the influence of swing grinding parameters on machining surface quality of large-width cam

Experimental study of the influence of swing grinding parameters on machining surface quality of large-width cam

Three-dimensional topography modelling and grinding performance evaluating of micro-structured CVD diamond grinding wheel

Micro-structured chemical vapour deposition (CVD) diamond grinding tools are attracting increasing attention in precision grinding and micro-grinding because of their advantages in low grinding forces, high machining accuracy and good wear resistance. A well-developed wheel topography model for this kind of emerging grinding tool not only can facilitate the analysis and optimization the grinding process, but also is the essential basics for the intelligent machining. In this paper, a novel three-dimensional surface topography model of original CVD diamond grinding wheels was firstly established based on the multiple random data of the shape, size, posture and distribution of the CVD diamond grains. And the ground surface topography model was simulated depending on the established wheel model and grinding kinematics. Secondly, the models were verified by the results of grinding experiments in the means of topographical characteristics, surface roughness and PSD. Then, the influence of grinding parameters and wheel wear on the grinding performance of CVD diamond wheels was discussed. Finally, the micro-structured CVD grinding wheel models were presented by coupling different forms of micro-structures. And the effects of micro-structure parameters including widths, inclination angles, structuring ratios and types on the grinding performance of micro-structured CVD diamond wheels were investigated quantitatively. This study provides a quantitative and effective method for the design of CVD diamond grinding wheels and their surface structuring. Furthermore, the proposed micro-structured analysis method is also available for other structured grinding wheels.

Profile Evolution and Cross-Process Collaboration Strategy of Bearing Raceway by Centerless Grinding and Electrochemical Mechanical Machining.

Roundness is one of the most important evaluation indexes of rotary parts. The formation and change of roundness in the machining of parts is essentially the formation and genetic process of profile. Centerless positioning machining is one of the main surface finishing methods of rotary parts. The rounding mechanism of centerless positioning machining determines its unique roundness profile formation and genetic characteristics. How to eliminate the roundness error of centerless positioning machining has become one of the important issues in the research of high-precision rotary part machining. This paper explores the influence of process parameters on the roundness error from the perspective of profile evolution during centerless grinding and electrochemical mechanical machining, with the aim of providing a cross-process collaboration strategy for improving bearing raceway accuracy. Through an experiment of centerless grinding, the influence law and mechanism of process parameters on the profile are discussed. On this basis, electrochemical mechanical machining experiments are designed to explore the variation rules and mechanisms of different profile shapes in the machining process. The cross-process collaboration strategy is studied, and reasonable parameters of centerless grinding and electrochemical mechanical machining are determined. The results show that in the centerless grinding stage, increasing the support plate angle can form a multiple-lobe profile with high frequency within a wide range of process parameters. Electrochemical mechanical machining can effectively smooth the high-frequency profile and appropriately expanding the cathode coverage can improve the roundness error and reduce the requirement of initial accuracy of a multiple-lobe profile workpiece to a certain extent. Therefore, the combined machining technology of "centerless grinding + electrochemical mechanical machining" provides an efficient technical means to realize the precision machining of rotary parts such as bearing raceways.

Исследование взаимосвязи режущей способности инструмента с параметрами акустического сигнала в процессе профильного шлифования

Introduction. Modern mechanical engineering is closely connected with digital production management technologies, for which an important aspect is the collection of reliable information about the current state of the systems. Acoustic methods of current control of the tool cutting ability possess significant potential due to the possibility of continuously obtaining up-to-date data on the parameters of machining process. Profile grinding is one of the widespread methods of machining surfaces of complex configuration. The high importance of this method lies in the high degree of responsibility of shaped parts obtained with it. The wear parameter of profiled grinding wheels needs current control to the same extent as other types of cutting tools. At the same time, acoustic methods of research have not found wide application in relation to profile grinding. In view of this, the present work is aimed at studying the influence of the tool wear rate on the acoustic characteristics of grinding when using grinding wheels of different profiles. Purpose of work is to determine the acoustic parameters of profile grinding with application of planar grinding scheme as it wears out in comparison with analogical process with application of straight profile grinding wheel. As the basic methods of research an experiment is used to study the acoustic phenomena accompanying grinding with application of wheels of different profile. An analysis of the acoustic signal of grinding is carried out, as well as an analysis of the spectrum of its frequency composition. The frequencies of natural vibrations of grinding wheels of different profiles are investigated, its sound index is determined as a criterion for evaluating its characteristics. Acoustic characteristics of the grinding process with the use of grinding wheels of different profiles are compared. Regression analysis of acoustic data obtained as a result of the experiment is also used. Results and discussion. Spectrograms of frequencies of natural vibrations of the wheels under research, as well as a number of spectrograms of the acoustic signal accompanying the processing process for various technological conditions are received. As a result of comparing the obtained spectrograms, the informative frequencies of the grinding processes are determined. Mathematical models of sound level dependence on the value of periodic vertical feed St at depth t and processing time T are developed. It is established that the value of periodic vertical feed St at depth t has a greater influence on the acoustic index in comparison with the machining duration T. Practical significance and prospects of the results of the work lies in the possibility of increasing the efficiency of profile grinding processes due to the rational use of the tool availability.

Optimization of Grinding Process of Sunflower Meal for Obtaining Protein-Enriched Fractions

In this study, dry fractionation process was proposed in order to obtain protein-enriched sunflower meal fractions. The process includes two-stage grinding using a hammer mill and a roll mill, and fractionation of sunflower meal by sieving. Central composite design (CCD) with four variables on three levels within response surface methodology was applied in order to estimate the influence of grinding parameters (sieve openings diameter of the hammer mill: 2, 4, and 6 mm, roll gap: 0.15, 0.2, and 0.25 mm, feed rate: 0.1, 0.175, and 0.25 kg/cm min, and roll speed: 400, 500, and 600 rpm) on responses (protein content, fraction yield and grinding energy consumption). Sieve openings diameter expressed the highest impact on fraction yield while roll gap expressed the most dominant influence on protein content in the fraction and grinding energy consumption. The highest protein content obtained was 48.06%(dm) with fraction yield of 77.22%. A multi-response optimization procedure was performed and optimal values were: sieve openings diameter of 2 mm, roll gap of 0.25 mm, feed rate of 0.2 kg/cm min, and roll speed of 400 rpm, while predicted values for a desired range of responses were: protein content 45.5%(dm), fraction yield 77.89%, and grinding energy consumption 8.31 Wh/kg.

Molecular dynamics simulation-based microstructure evolution and subsurface damage of Fe-Ni alloy grinding

PurposeMolecular dynamics is an emerging simulation technique in the field of machining in recent years. Many researchers have tried to simulate different processing methods of various materials with the theory of molecular dynamics (MD), and some preliminary conclusions have been obtained. However, the application of MD simulation is more limited compared with traditional finite element model (FEM) simulation technique due to the complex modeling approach and long computation time. Therefore, more studies on the MD simulations are required to provide a reliable theoretical basis for the nanoscale interpretation of grinding process. This study investigates the crystal structures, dislocations, force, temperature and subsurface damage (SSD) in the grinding of iron-nickel alloy using MD analysis.Design/methodology/approach In this study the simulation model is established on the basis of the workpiece and single cubic boron nitride (CBN) grit with embedded atom method and Morse potentials describing the forces and energies between different atoms. The effects of grinding parameters on the material microstructure are studied based on the simulation results.FindingsWhen CBN grit goes through one of the grains, the arrangement of atoms within the grain will be disordered, but other grains will not be easily deformed due to the protection of the grain boundaries. Higher grinding speed and larger cutting depth can cause greater impact of grit on the atoms, and more body-centered cubic (BCC) structures will be destroyed. The dislocations will appear in grain boundaries due to the rearrangement of atoms in grinding. The increase of grinding speed results in the more transformation from BCC to amorphous structures.Originality/valueThis study is aimed to study the grinding of Fe-Ni alloy (maraging steel) with single grit through MD simulation method, and to reveal the microstructure evolution within the affected range of SSD layer in the workpiece. The simulation model of polycrystalline structure of Fe-Ni maraging steel and grinding process of single CBN grit is constructed based on the Voronoi algorithm. The atomic accumulation, transformation of crystal structures, evolution of dislocations as well as the generation of SSD are discussed according to the simulation results.

Optimization of Grinding Parameters of Tool Steel by the Soft Computing Technique.

Grinding is one of the most complex and accurate machining processes, and the efficiency of the grinding wheel depends significantly on its surface properties. This work aims to propose an algorithmic manner that reduces the cost and time to conduct grinding of an optimized DIN 1.2080 tool steel (SPK) using a soft computing technique to obtain the best combination of input parameters including depth of cut (20, 40, 60 μm), wheel speed (15, 20, 25 m/s), feed rate (100, 300, 500 mm/s), and incidence angle (0, 30, 45 de grees) with respect to output parameters consisting of average surface roughness and specific grinding energy. According to the input parameters and their levels, an experiment using fractional factorial design of experiment (RFDOE) was designed. Later on, two parallel feed-forward backpropagation (FFBPNN) networks with similar topology made up of 4, 11, and 1 units in their input, hidden, and output layers are trained, respectively. After sensitivity analyses of networks for determination of the relative importance of input variables, a genetic algorithm (GA) adopting linear programming (LP) based on Euclidean distance is coupled to networks to seek out the best combinations of input parameters that result in minimum average surface roughness and minimum specific grinding energy. The findings revealed that RFDOE provides valid data for training FFBP networks with a total goodness value of more than 1.99 in both cases. The sensitivity analyses showed that feed rate (38.97%) and incidence angle (33.94%) contribute the most in the case of average surface roughness and specific grinding energy networks, respectively. Despite the similar surface quality based on scanning electron microscopy (SEM), the optimization resulted in an optimized condition of the depth of cut of 25.23 μm, wheel speed of 15.02 mm/s, feed rate of 369.45 mm/s, and incidence angle of 44.98 de grees, which had a lower cost value (0.0146) than the optimum one (0.0953). Thus, this study highlights that RFDOE with a hybrid optimization using FFBP networks-GA/LP can effectively minimize both average surface roughness and specific grinding energy of SPK.

Analysis and Prediction of Grind-Hardening Surface Roughness Based on Response Surface Methodology-BP Neural Network

Surface morphology and surface roughness are very important properties used to assess the quality of grind-hardening surfaces. In this study, grind-hardening tests for 42CrMo steel were designed using the response surface methodology to reveal the surface morphological characteristics of the grind-hardening surface and the effects of grinding parameters on its roughness. The results showed considerable grinding damage in both the cutting-in and cutting-out areas of the grind-hardened surface, while the middle area was more stable. More specifically, the cutting-in area showed much bonding and damage, while the cutting-out area showed more microcracks. Under the conditions of this test, the surface roughness tended to increase with the increase in cutting depth and workpiece feed speed. The effect of grinding line speed on the grind-hardening surface roughness was not significant. The significance of the effects of grinding parameters on surface roughness ranked as: cutting depth > workpiece feed speed > grinding speed. In turn, a response surface methodology-BP neural network prediction model for the surface roughness of grind-hardening was developed, whose feasibility and validity were confirmed by the experimental results. The model achieved surface roughness prediction of the grind-hardening process with a mean relative error of 2.86%.

RETRACTED ARTICLE: Minimization of Surface Roughness and Residual Stress in Grinding Operations of Inconel 718

The residual stress and surface roughness enhancement of ground surfaces can decrease the lifetime of workpiece by reducing its fatigue life. It is critical to accurately predict and minimize the residual stress and surface toughness of ground surfaces in order to enhance efficiency of part production using grinding operations. A virtual machining system is developed in the research work to minimize the surface integrity and residual stress during grinding operations of Inconel 718. The cutting temperature during grinding operations is calculated using the Inconel alloy Johnson–Cook law models. Then, using the finite element method, residual stress during the grinding operation is estimated. Utilizing the established virtual machining method, the surface roughness is predicted in the study. Using the Taguchi optimization approach, the grinding parameters of depth of cut and feed velocity are optimized in order to reduce surface roughness as well as residual stress throughout grinding operations on Inconel 718 superalloy. To confirm the effectiveness of the developed technique in the study, simulation and experimentation are conducted. As a result, the quality as well as reliability of the ground surfaces can be enhanced by using the developed virtual machining system in the study to minimize the surface roughness and residual stress of produced parts using grinding operations.

Detection and Prediction of Chipping in Wafer Grinding Based on Dicing Signal

Simple regression cannot wholly analyze large-scale wafer backside wall chipping because the wafer grinding process encounters many problems, such as collected data missing, data showing a non-linear distribution, and correlated hidden parameters lost. The objective of this study is to propose a novel approach to solving this problem. First, this study uses time series, random forest, importance analysis, and correlation analysis to analyze the signals of wafer grinding to screen out key grinding parameters. Then, we use PCA and Barnes-Hut t-SNE to reduce the dimensionality of the key grinding parameters and compare their corresponding heat maps to find out which dimensionality reduction method is more sensitive to the chipping phenomenon. Finally, this study imported the more sensitive dimensionality reduction data into the Data Driven-Bidirectional LSTM (DD-BLSTM) model for training and predicting the wafer chipping. It can adjust the key grinding parameters in time to reduce the occurrence of large-scale wafer chipping and can effectively improve the degree of deterioration of the grinding blade. As a result, the blades can initially grind three pieces of the wafers without replacement and successfully expand to more than eight pieces of the wafer. The accuracy of wafer chipping prediction using DD-BLSTM with Barnes-Hut t-SNE dimensionality reduction can achieve 93.14%.

A prediction of blend grinding result based on individual ore size measurements and grinding tests

Dry ball mills of Tata Steel IJmuiden’s pelletizing plant grind a blend of iron ores, coke breeze and mineral additives. Blend composition can be adjusted depending on raw material supply and product demand. A grinding prediction method on blends has been developed in order to aid improvement of blend selection. A batch testing procedure on individual ores was applied. Parameters describing grinding kinetics were determined by using simulation and fitting to the results of the tests. The grinding of certain ore mixtures was simulated using the obtained parameters of the individual ores. The calculated particle size distributions were compared to laboratory grinding results of the mixtures. Grinding parameters of each ore were subsequently summarised in a single parameter, being the time required in a laboratory mill to achieve a specified target average particle diameter. The incorporation of the grinding time into linear models improved the prediction of product quality from the industrial grinding system. Results and mean average error of this prediction were determined by means of cross validation.