Optimization Of Grinding Parameters Research Articles

Improvement of useful flow rate of grinding fluid with simulation schemes

In previous studies, the improvement of the useful flow and flow rate of grinding fluid has been investigated via modeling, simulation, and experiment. Optimized grinding parameters have been achieved. A detailed assessment of the improvement in the useful flow rate of grinding fluid, which optimizes the grinding fluid supply, has been published in the International Journal of Advanced Manufacturing Technology (Li et al. Int J Adv Manuf Technol 75:1587–1604, 2014). Then, a detailed experimental study on the improvement in the useful flow rate of grinding fluid has been published in the International Journal of Advanced Manufacturing Technology (Li et al. Int J Adv Manuf Technol 1–10. doi: 10.1007/s00170-015-7230-z , 2015), in which the influence of grinding wheel speed, grinding fluid jet velocity, particle size, and bulk porosity on useful flow and useful flow rate was analyzed. In this paper, a new method of air scraper is presented and simulated with focus on the air boundary layer and reflux around the grinding wheel. In view of the influence of the gas barrier of grinding wheels on the effective supply of grinding fluid, the effect of the scraper on the gas barrier layer was analyzed through the grinding flow field simulation under unified grinding parameters. Using the air scraper to destroy the gas barrier layer is proposed, and a supply scheme is designed to improve the useful flow rate. Results show that using the scraper has a certain effect on the weakening of the grinding gas barrier layer. In the grinding process, using the scraper can reduce the obstacles to grinding fluid supply, thereby improving the useful flow of grinding fluid into grinding wheel workpieces. The distance between the front end of the plane scraper and the grinding wheel is 10 μm, with a large circular boot-shaped nozzle. Alternatively, the distance between the front end of the nozzle and the grinding wheel surface is 50 μm, which can increase the useful rate of flow of grinding fluid.

Comparative study on grinding of thin-walled and honeycomb-structured components with two CBN wheels

In the grinding of thin-walled and honeycomb-structured components made up of Hastelloy, undesired burrs are often created. The formed burrs negatively affect the quality of the products. Subsequent deburring increases overall manufacturing process time and cost. This work was focused on development of high-speed grinding process and grinding strategies to reduce burr size and improve ground surface quality. An electroplated Cubic Boron Nitride (CBN) wheel with miniature concave and convex asperities on its circumferential working surface was developed. Grinding performance with the designed CBN wheel was compared with a normal CBN wheel without surface asperities. Special fixtures with the function of adjusting honeycomb orientation (change of grinding direction) were purposely designed and fabricated. Design of experiment (DOE) was adopted for optimization of grinding parameters. It was found that less burr (even burr-free) grinding was achieved with the utilization of the specially designed CBN wheel with concave and convex asperities under optimal grinding conditions investigated, i.e., rotational speed of 5,000 RPM, depth of cut of 25 μm, and feed rate of 7,500 mm/min.

Optimization of Roughness and Residual Stresses in Path Controlled Grinding of Crankpin

Crankpin is generally subjected to high thermal and cyclic loads when working. Surface roughness and residual stresses greatly influences the final running characteristics of crankpin. Path controlled grinding process has been used in automotive powertrain industry. The grinding conditions are periodically changing between grinding wheel and crankpin due to the existence of the eccentricity of crankpin and constant rotation speed of crankshaft. It leads to the variation of surface roughness and residual stresses on circumference of crankpin. So the optimization of grinding parameters in crankshaft grinding is essential. This paper presents an investigation to evaluate variation of surface roughness and residual stress along circumference in path controlled grinding of crankpin. The effects of the speed and speed ratio were analyzed in detail with constant rotation speed of crankshaft. It is found that up-grinding and down-grinding exist during one revolution cycle. The results show the surface roughness Ra always keeps below 0.25μm in all the grinding conditions, and the variations of surface roughness are little along circumference. The highly compressive residual stresses level after grinding is obtained on pin bearing. Compared to the variation of roughness, the variation of residual stress along circumference is large. Based on the results, the lower crankshaft rotational speed, lower grinding depth, and higher wheel speed are suggested to be used in the path controlled grinding of crankpin harden by induction surface hardening.

Noisy-power dissipation and efficiency in NiO/Fe2O3 wet grinding by planetary ball mill

The relationship between the efficiency of NiO/Fe2O3 wet grinding and noisy-power dissipation was studied. The optimal grinding parameters were found as: a slurry water content of 64.10%–85.47%, ball number ratio of 360/20, revolution speed of 300.9 r/min, powder-filling ratio of 10.88%, ball-filling ratio of 20.53%–23.88%, and grinding time of approximately 6 h. The discrete element method (DEM) was employed to analyze relationship between the noisy-power dissipation and the grinding efficiency, and equations describing the relationship were derived. The mean particle size of the ground powder decreased with a decrease in the degree of noisy-power dissipation, while the grinding efficiency and the amount of specific impact power used decreased with an increase in the degree of noisy-power dissipation.

Experimental Research on Surface Roughness and Topography of Grinding Ultra-High Strength Steel Aermet100 with CBN Wheel

In order to optimize grinding parameters and control surface roughness in precision machining, the grinding experiment of Ultra-high strength steel Aermet100 was conducted based on three levels and three factors. The influence of grinding parameters on surface roughness was investigated, and corresponding 3D surface topography was observed. Experimental results indicate that for CBN wheel, the surface roughness decreases with the increase of workpiece speed and wheel speed; it increases strongly when grinding depth increasing; and the wheel speed has little influence on surface roughness. The optimum surface roughness can be achieved when adopting vs=24 m/s, vw=13 m/min, ap=0.01 mm within experimental parameters, the surface roughness value is less than 0.40 μm.

Dry Fine Grinding of Calcite Powder by Stirred Mill

The demand for fine powder is increasing in many fields such as chemical, pharmaceutical, and material industries. Therefore, research in fine grinding has gained in importance. In this study, the effects of various operating parameters, such as grinding time (min), stirrer speed (rpm), feed quantity (% of ball weight), and ball filling ratio (%) on fine grinding of calcite powder (CaCO3) (d 50 = 34.04 µm) were studied using a laboratory vertical stirred mill under dry conditions. A series of laboratory experiments using 24 full factorial designs was conducted to determine the optimum grinding parameters. The main and interaction effects on the volumetric surface area (Sv) (m2/cm3) of the ground product were evaluated using Yates’ analysis. The grinding time, media filling ratio, and stirrer speed play distinct roles (positive) in product surface area and fineness.

Multi-Objective Optimization in Traverse Cut Cylindrical Grinding

Present work aims to study the effects of grinding parameters on surface roughness (Ra and Rq) in traverse cut cylindrical grinding process, while grinding of stainless steel. Experiments have been conducted as per L9 orthogonal array of Taguchi method. Grey based Taguchi method has been used to optimize the grinding parameters to minimize surface roughness parameters Ra and Rq simultaneously. The analysis of signal to noise ratio has been applied to investigate the effects of grinding parameters and optimize them. From the results of this study, longitudinal feed is identified as the most influential grinding parameter on surface roughness. The optimization methodology used in the present study of cylindrical grinding process is very useful to determine the optimum grinding parameters for minimum surface roughness. In the manufacturing industry, surface finish of any machined product is very important to determine the product’s quality, in so far as cylindrical jobs are concerned, it is obviously true as well. Cylindrical grinding is one of the important manufacturing processes, used for producing accurate and good surface finish cylindrical rods. Obtaining the better surface finish jobs in cylindrical grinding is mainly depends on correct selection of grinding parameters. Optimum parameter selection is difficult task in cylindrical grinding process because of its complexity while solving it. But, through systematic optimization methodology like design of experiments (DoE), it is possible to select optimum parametric combination. The present work is an attempt to optimize grinding parameters to minimize surface finish by using DoE’s Taguchi method. Good surface finish is demanded in many engineering and domestic applications, because, it is an important aspect of tolerance of finished part; it minimizes friction and wear, thereby enhancing operating hours of the components. The arithmetic average height parameter (Ra) is an important roughness parameter, which most universally accepted and used roughness parameter to describe the quality of machined part. Review of available literature shows that Ra has been focus of most of the studies, but, Ra parameter alonely can’t provide full description of surface. Root mean square roughness (Rq) is also an important parameter used to specify quality of the machined part. It is more sensitive than Ra. If the number of roughness parameters used is increased, full description of the surface profile can be obtained [1]. The present study aims at consideration of two roughness parameters Ra and Rq simultaneously for the surface roughness generated in cylindrical grinding operation. Extensive literature survey has been made on optimization of process parameters in different machining operations for single objective optimization problem using Taguchi method [2] and multi objective optimization by using Taguchi method combined with grey relation analysis [3, 4]. Some of the previous studies are included here, Taguchi methodology’s tools such as the orthogonal array, signal to noise ratio, factor effect analysis and analysis of variance were used to analyze and optimize the process parameters such as speed, feed, infeed and mode of dressing in surface grinding[5]. Similar technique was used in CNC milling operation to optimize the surface roughness, this study considers feed rate, spindle speed and depth of cut as control factors, operating chamber temperature as noise factor and the usage of different tool inserts in the same specification, which introduced tool condition and dimensional variability. Finally, significant factors on surface roughness were found by using analysis of variance and optimal cutting combination determined by seeking the best surface roughness [6]. Reference [7] used application of Taguchi method, analysis of variance for minimization of delamination influenced by drilling parameters and drill point

Precision Vertical Grinding of Cemented Tungsten Carbide Using CBN Wheels

A set of precision vertical grinding experiment on WC-CO cemented tungsten carbide materials was carried out using cubic boron nitride (CBN) grinding wheel. Different grinding parameters such as rotation speeds of workpiece, feed rates and grinding depths were employed during precision vertical grinding. Surface roughness was measured for studying the grinding charateristics of WC-CO cemented tungsten carbide in this removal mode. Optimal grinding parameters were obtained by changing the process parameters. The research results have an important significance to improve grinding quality and efficiency for precision grinding cemented tungsten carbide materials.

Rotary Ultrasonic-Assisted Grinding of Ceramic Material

The engineering ceramic material is hard to machining with the hard and brittle characteristics, so we are using a precision machining method of the rotary ultrasonic assisted grinding. In this paper, a research on the rotary ultrasonic assisted grinding mechanism of zirconia ceramic material is described. We use an experimental method of the orthogonal combination to complete an experiment of the rotary ultrasonic grinding of zirconia ceramic material. According to the experiment, we explore how the various grinding parameters affect the surface roughness, and determine a set of the optimal grinding parameters.

Optimal Design of the Grinding Parameter on Zr-4 Cladding Tubes Abrasive Belt Grinding Based on BP and GA

This paper used BP(Neural Networks) to establish parameter optimization design method for Zr-4 clad tube belt grinding. The BP can get strong nonlinear mapping capability through training, obtain better grinding parameter model; GA(Genetic Algorithm) is not dependent on the specific situation of the problem and it has strong robustness, so it can provides optimization framework for Zr-4 clad tube belt grinding parameter optimization design of nonlinear optimization. This paper optimized the single objective and multi-objective of the abrasive belt life n and grinding roughness Rz, obtained satisfied optimization results and the corresponding grinding conditions.

Optimization of Grinding Parameters for Minimum Surface Roughness by Taguchi Parametric Optimization Technique

Cylindrical grinding is one of the important metal cutting processes used extensively in the finishing operations. Surface finish is the important output responses in the production with respect to quantity and quality respectively. The Experiments are conducted on universal tool and cutter grinding machine with L9 Orthogonal array with input machining variables as work speed, grinding wheel grades and hardness of material. The developed model can be used by the different manufacturing firms to select right combination of machining parameters to achieve an optimal surface roughness (Ra).The results reveals surface roughness (Ra).The predicted optimal values for Ra for Cylindrical grinding process is 1.07 Ra respectively. The results are further confirmed by conducting confirmation experiments.

Modeling and optimization of cylindrical grinding of Al/SiC composites using genetic algorithms

The Al/SiC composites have received more commercial attention than other kinds of Metal Matrix Composites (MMCs) due to their high performance. However, a continuing problem with MMCs is that they are difficult to machine, due to the hardness and abrasive nature of the SiC particles. Grinding is often the method of choice for machining Al/SiC composites to acquire high dimensional accuracy and surface finish in large scale production. Based on the full factorial design (34), a total of 81 experiments, each having a combination of different levels of variables, are carried out to study the effect of grinding parameters such as wheel velocity, work piece velocity, feed and depth of cut on the responses such as tangential grinding force, roughness and grinding temperature. Modeling and optimization place a vital role in controlling any process for improved product quality, high productivity and low cost. In the present work, experimental results are used to calculate the analysis of variance (ANOVA) which explains the significance of the parameters on the responses. Based on the results of ANOVA, a mathematical model is formulated using multiple regression method. A genetic algorithm (GA) based optimization procedure has been developed to optimize the grinding parameters for maximum material removal by imposing constraints on roughness. This methodology would be useful for identifying the optimum grinding parameters in order to achieve the required material removal rate (MRR).

Study on the Simulation Model and Characteristics of High-Speed Grinding for Ceramics

Engineering ceramic machining would bring out several kinds of surface damage owing to its hard and brittle nature. In this paper, a simulation model of single-grit grinding for silicon carbide (Sic) was established to explore the high-speed grinding mechanism. The material behavior was described with the Johnson-Holmquist Ⅱ (JH-2) model. According to the simulation experiment results, the optimal grinding parameters to achieve ductile grinding for Sic has been analyzed, which would provide theoretical basis and take surface damage under control.

A Comparison of Back Grinding Processes for Bare Silicon and Through-Silicon Via Wafers Using Numerical Simulations

The optimization of grinding parameters for silicon wafers is necessary in order to reduce the likelihood of residual stresses and crack nucleation in the machined surface and improve the reliability of electronic packages. This paper describes numerical simulations performed to characterize the back grinding process for bare silicon wafers and through-silicon via (TSV) wafers using the finite element code ABAQUS. The grinding of the two wafer types was performed by simulating the motion of a diamond particle cutting through successive silicon and TSV layers. The silicon material was modeled using orthotropic elasticity and isotropic plasticity, while the copper vias were modeled using isotropic elasticity and Johnson-Cook plasticity. The polyethylene terephthalate (PET) material used as a backing tape for the silicon wafer was modeled using the Mooney-Rivlin hyperelastic model. The computed residual stresses and the plastic deformation in the superficial layer of the ground wafer were compared with experimental values and good correlation was observed. The simulation results can be used to better understand the local stresses and strain fields in both bare silicon and TSV wafers, and to quantify the effect of the copper vias on the wafer properties during and after grinding.

Optimization of Precision Grinding Parameters of Silicon for Surface Roughness Based on Taguchi Method

Silicon being a typical hard-brittle material is difficult to machine to a good surface finish. Although ductile-mode machining (DMM) is often employed to machine this advanced material but this technique requires the use of expensive ultra-precision machine tools therefore limiting its applicability. However, by proper selection of grinding parameters, precision grinding which can be performed on conventional machine tools can be used to generate massive ductile surfaces thereby reducing the polishing time and improving the surface quality. Precision grinding should be planned with reliability in advance and the process has to be performed with high rates of reproducibility. Therefore, this study investigated the effect and optimization of grinding parameters using Taguchi optimization technique during precision grinding of silicon. Experimental studies were conducted under varying depths of cut, feed rates and spindle speeds. An orthogonal array (OA), signal-to-noise (S/N) ratio and the analysis of variance (ANOVA) were employed to find the minimum surface roughness value and to analyze the effect of the grinding parameters on the surface roughness. Confirmation tests were carried out in order to illustrate the effectiveness of the Taguchi method. The results show that feed rate mostly affected the surface roughness. The predicted roughness (Ra) of 34 nm was in agreement with the confirmation tests. Massive ductilestreaked surface was also found corresponding to the minimal surface finish determined from the optimal levels.

Effect of Various Operating Factors on Wet Stirred Mill Performance

In this study, the effects of various operating factors, such as initial particle size, feed quantity, filling volume of the ball, and ball size distribution on fine grinding of calcite powders (CaCO3) were studied using a laboratory stirred mill under wet conditions. A series of laboratory experiments using 24 full factorial designs was conducted to determine the optimum grinding parameters. The main and interaction effects on the specific surface area (m2/g) of the ground product were evaluated using Yates' analysis. The test results showed that the main factors that influence the mill grinding performance are the feed quantity and the ball size distribution.

Study on the Simulation Model and High-Speed Characteristics of Cylindrical Grinding

The existing research shows that high-speed grinding is the main way to machining the common materials and difficult-to-machine materials efficiently and critically. However, the research on mechanism and high-speed characteristics of high-speed cylindrical grinding is few searched. Based on three-dimensional simulation software DEFORM-3D, the simulation model of high speed cylindrical grinding with single grit was established, and the relevant experiment of 3D simulation for high speed cylindrical grinding process was processed. In this paper, the impact of the grinding parameters, such as wheel speed and depth of cut on the grinding force and grinding temperature is explored through analyzing the variation of strain rate, grinding force and temperature, and found that the increasing strain rate can lead to the increase in grinding force and temperature. According to the simulation experiment results, the control model of grinding temperature for prediction of grinding temperature and optimization of grinding parameters, is analyzed and developed in the end. The engineering experiment, conducted on the high speed cylindrical grinder and measured grinding temperature with thermal infrared imager, has been carried out in this study. Engineering and simulation experiments results show good match, for grinding temperature would decline with the increasing wheel speed when the grinding depth keeps constant, and thus can reduce grinding burn, improve the surface quality of workpiece.

A study on the effect of process parameters in stirred ball mill

An experimental study on the fine grinding of calcite powder ( d 50 = 62.16 μm) using a 0.75 l laboratory stirred ball mill has been carried out. The effects of various operating factors, such as grinding time (min), stirrer speed (rpm), slurry density (wt.%) and ball filling ratio on fine grinding was studied under batch wet conditions using alumina balls, 95% purity with diameters 3.5–4.0 mm. A series of laboratory experiments using 2 4 full factorial designs was conducted to determine the optimum grinding parameters. The test results showed that the stirrer speed and grinding time have strong effects on the grinding efficiency, based on the value of specific surface area (m 2/g).

Influence of Radial Depth of Grinding and Finishing Process on Surface Residual Stresses in Grinding AF1410 Ultrahigh Strength Steel

AF1410 steel is a kind of high alloy secondary hardening ultrahigh strength steel, which is developed for structural applications where the combination of high strength and high fracture toughness is required. The distribution of residual stresses affects the fatigue life and stress corrosion resistance of the components in service. The distribution of surface residual stresses on the components should be controlled by the machining process. Little investigation about the residual stresses on AF1410 steel had been studied previously. In this study, two AF1410 cylindrical workpieces were machined by cylindrical grinding with a white alumina (WA) grinding wheel and under water base cooling fluid. Two groups of experiments were set to investigate the influences of different radial depths of grinding and the finishing process on the residual stresses. The residual stresses along grinding and feed directions were measured respectively using X-ray method. The rule of the residual stresses variety with the radial depth of grinding (ap) was studied. The reasons causing the distinctions of the residual stresses between two groups of experiments were analyzed and the optimized grinding parameters were obtained.

Determination of the Optimal Ball Grinding Parameters for the Bio-Ceramics ZrO<sub>2</sub> on a PC-Based Multi-Axis CNC Engraving Machine

The objective of this study is to determine the optimal ball grinding parameters of the bio-ceramics ZrO2 by executing the Taguchi’s L18 orthogonal array experiment, analysis of variation (ANOVA), and the full factorial experiment on a PC-based multi-axis CNC engraving machine. The manufacture of a ZrO2 coping using the optimal ball grinding parameters has also been studied based on a tooth plaster model via reverse engineering technique. The 3D data points of a tooth plaster model were digitized by the developed on-machine measurement system on a PC-based CNC multi-axis engraving machine by integrating a circular triangulation laser probe with the machine and a PC. A CAD model of a coping could then be constructed by Pro/Engineer software, based on the digitized 3D data points. With the help of the PowerMill CAM software, the machining path of a coping has been simulated, and the correspondent NC codes have been generated to fabricate the ZrO2 coping using the determined optimal ball grinding parameters, on the CNC multi-axis engraving machine. The average surface roughness of Ra=0.49 um for the ground ZrO2 ceramics coping could be obtained by utilizing the optimal flat surface grinding parameters.