Grinding Ratio Research Articles

Comprehensive investigation into the effects of relative grinding direction on abrasive belt grinding process

Abrasive belt grinding has become widely used in industries due to its virtues of flexibility, applicability, and cost-efficiency. However, the relative grinding direction, namely up or down grinding, has often been overlooked and unclear on the grinding process. Thus, this paper implemented an experimental comparative analysis between up and down face grinding, studying grinding ratio, surface roughness and surface residual stress. The results indicated that the down grinding provided less material removal but with a higher grinding ratio. The grinding ratio of down grinding (Rdg) was always larger than that of the up grinding (Rug), and their ratio (Rdg/Rug) rose along with processing time, implying the down grinding with increasingly high grinding efficiency. The up grinding induced higher Ra, Rsm, and Rq because of the deeper indentation of approximately conical abrasives. As for residual stresses in the external surface layer, σ11 of the up grinding was on average 2.23 times as large as that of the down grinding, both in the form of compressive residual stresses. The multi-abrasive scratching finite element modeling (FEM) discussed the influence of plastic flow on residual stress distribution on the ground surface.

Tool wear behavior of alumina abrasive wheels during grinding FGH96 powder metallurgy nickel-based superalloy

The tool wear behavior of microcrystalline alumina (MA) and brown alumina (BA) abrasive wheels were comparatively studied during grinding FGH96 powder metallurgy nickel-based superalloy. The grinding ratio, radial wear and grinding force were quantitatively analyzed. The influences of tool wear on surface morphology were discussed. The results suggest that grinding force and radial wear of MA wheel is lower than that of BA wheel. Serious tool wear occurs on both the MA and BA wheel from grinding ratio which is less than 1.8 because of the material adhesion and pores clogging. Meanwhile, several defects were found on the ground surface.

Friction and wear performance of a copper-based bond emery wheel for rail grinding

Abstract In this paper, a copper-based bond emery wheel was prepared by vacuum hot pressing sintering through powder metallurgy. The effects of various bond contents on the grinding performance of the copperbased bond grinding wheel were studied using a self-made experimental device; the friction coefficients between the friction pairs and roughness of the grinded rail surface were also obtained. The results show that the grinding wheel had the best grinding performance when the content of the copper-based bond was at 35 wt.-%, the friction coefficient 0.29, the grinding ratio 81.34, and the surface roughness 7.191 μm, which meet the roughness requirements of rail grinding. The microstructure of the rail surface and debris after grinding were studied by scanning electron microscope and energy spectrum analysis. Adhesive wear, abrasive wear, oxidation wear and delamination wear occurred during the friction and wear process. The grinding behavior of grinding wheels was analyzed in accordance with the experimental results.

Friction and wear performance of a copper-based bond emery wheel for rail grinding

Abstract In this paper, a copper-based bond emery wheel was prepared by vacuum hot pressing sintering through powder metallurgy. The effects of various bond contents on the grinding performance of the copperbased bond grinding wheel were studied using a self-made experimental device; the friction coefficients between the friction pairs and roughness of the grinded rail surface were also obtained. The results show that the grinding wheel had the best grinding performance when the content of the copper-based bond was at 35 wt.-%, the friction coefficient 0.29, the grinding ratio 81.34, and the surface roughness 7.191 μm, which meet the roughness requirements of rail grinding. The microstructure of the rail surface and debris after grinding were studied by scanning electron microscope and energy spectrum analysis. Adhesive wear, abrasive wear, oxidation wear and delamination wear occurred during the friction and wear process. The grinding behavior of grinding wheels was analyzed in accordance with the experimental results.

Performance comparison of seeded-gel and CBN grinding wheels for cylindrical plunge grinding of 100Cr6 steel

The selection of the grinding wheel is an important step during the process planning of grinding operations, especially for high-quality small components of hardened steel. The correct choice of the grinding wheel and the proper selection of cutting parameters can provide ground surfaces with high quality and positively affect the economic aspects of the process. The present work compares the performance of seeded-gel and CBN grinding wheels in external cylindrical plunge grinding of 100Cr6 steel in a range of high peripheral speeds, where it is possible to use both grinding wheels. The comparison was made taking into account the workpiece surface roughness and indices like the grinding ratio, specific grinding energy and grinding efficiency. The use of the CBN grinding wheel resulted in lower surface roughness values than those obtained with the seeded-gel grinding wheel. For both grinding wheels, there was a tendency that increasing peripheral speed reduces the surface roughness values. The best performance of the seeded-gel grinding wheel was found at 150 mm3/min/mm, where the grinding efficiency increased with the peripheral speed, and the highest value of all the performed experiments was achieved at 80 m/s. This value was approximately three times the grinding efficiency of the CBN grinding wheel under the same cutting conditions. The highest grinding efficiency for the CBN grinding wheel was achieved at 200 mm3/min/mm and 80 m/s. The grinding efficiency of the seeded-gel wheel dropped for this cutting condition due to higher wheel wear.

Study of the G-ratio of aluminium silicon carbide nano particles reinforced metal matrix composites

Grinding plays an essential role in obtaining high dimensional accuracy and surface finish. Three types of work pieces were used with different ratios of SiC (1%,2%,3%). When the composition of SiC increases, the G-ratio decreases. This type of material is highly used in aerospace applications due to its low density and good wear and corrosion resistance. It is genuinely believed that Al-SiC has tremendous potential for application in the aerospace industry. A critical role is played by grinding in achieving good surface finish and improved dimensional accuracy. Therefore, a strategy to improve the grinding rate and surface finish is important for economic production. In this research, the various grinding ratio was found out and results show that G-ratio is high when coolant is used and G-ratio is low when coolant is not used.

Experimental Investigation of Wearing Grinding Wheels After Machining Sintered Carbide

Abstract Solid cutting tools are widely applied in the machining of shape parts and mainly fabricated using the grinding operations. Solid cutting tools are of specific geometry and shape. The tool geometry is created by mutual movement grinding wheels and stock. In the grinding of its manufacturing, grinding wheels are worn out gradually with the grinding number increasing. The wearing grinding wheel has a significant influence on the accuracy geometry of the tool produced. The paper focuses on the wear of the grinding wheels based on diamonds, and the grinding wheels based on cubic boron nitride. The wear rate of the grinding wheels is affected by the properties of a grinding wheel, grinding conditions, and type of cutting material. A measure of the ability of a grinding wheel to remove material is given by the Grinding ratio. The grinding ratio (G ratio) is defined as the volume of material removed (Vw) divided by the volume of wheel wear (Vs). Periphery grinding wheels were used in the experiments. Cylindrical face grinding was used for the machining of sintered carbide stock with a diameter of 20 mm. The results of the experiment show that the diamond-based grinding wheels are more suitable for grinding sintered carbide.

An investigation on the dressing contact behavior between vitrified bonded CBN abrasive wheel and diamond grit dresser

Abstract In order to better understand the dressing behavior, an investigation was carried out to detect the contact zone between vitrified bonded cubic boron nitride (V-CBN) abrasive wheel and diamond grit dresser. The grinding experiment of single diamond grit dresser on V-CBN abrasive segment was designed and conducted to approach the actual dressing process. The moving trajectory during dressing was calculated and discussed. Acoustic emission (AE) signals were applied to evaluate the wear progression of V-CBN abrasive wheel. Results obtained discovered that the different trajectory length would result in different wear patterns of diamond grit dresser and vitrified bond of V-CBN abrasive wheel. With the increase of wear ratio, the AE root-mean-square (RMS) voltages also had an increasing trend during dressing V-CBN wheel. Furthermore, a shorter dressing trajectory length produced a lower and more stable surface roughness, a lower tool radial wear and a higher grinding ratio in the grinding experiment of Inconel 718 nickel-based superalloy.

SYSTEMS THINKING IN JAW CRUSHER ANALYSIS

It provides information on the method of system thinking, where the analysis of the crusher for grinding solid materials shows four hierarchical structure of the object - the jaw crusher. For a particle - a piece of material at the lowest hierarchical level, the influence of the infrastructure of the material and object on the stochastic grinding process is considered, which is characterized by probabilistic mathematical models. Moving to higher hierarchical levels, computer models of deterministic processes in the material and the crusher are given. It is preliminary shown that increasing the grinding ratio increases the efficiency of the material crushing plant.

Experimental Studies on the Centrifugal MQL-CCA Method of Applying Coolant during the Internal Cylindrical Grinding Process.

This paper presents the results of experimental research concerning the possibility of supporting the cooling function during internal cylindrical grinding using the minimum quantity lubrication (MQL) method by additional delivery of a compressed cooled air (CCL) stream. The article presents a description of a hybrid method of cooling and lubrication of the grinding zone integrating centrifugal (through a grinding wheel) lubrication with the minimum quantity of lubricant and cooling with a compressed cooled air stream generated by a cold air gun (CAG). The methodology and results of experimental studies are also presented in detail, with the aim of determining the influence of the application of the hybrid method of cooling and lubrication of the machining zone on the course and results of the internal cylindrical grinding process of 100Cr6 steel in comparison with other methods of cooling and lubrication, as well as compared with dry grinding. The research results obtained using the described hybrid method of cooling and lubrication of the grinding zone are related to the results obtained under the conditions of centrifugal MQL method, cooling with a stream of CCA, cooling and lubrication with a stream of oil-in-water emulsion delivered using the flood method, and dry grinding. The efficiency of the grinding process is evaluated (based on the average grinding power Pav, grinding wheel volumetric wear Vs, material removal Vw, and grinding ratio G), along with the thermal conditions of the process (based on the analysis of thermograms recorded by infrared thermal imaging method), the textures of machined surfaces (based on microtopography measured by contact profilometry), the state of residual stress in the surface layers of workpieces (determined by X-ray diffraction method), and the state of the grinding wheels’ active surfaces after grinding (based on microtopography measured by laser triangulation and images recorded with a digital measuring microscope). The obtained results of the analyses show that the application of the hybrid method allows for the longest wheel life among the five compared grinding methods, which is about 2.7 times the life of grinding wheels working under the flood cooling and centrifugal MQL methods, and as much as 8 times the life of grinding wheels working under the conditions of CCA only and dry grinding.

Vitrified bond diamond grinding wheel prepared by gel-casting with 3D printing molds

The vitrified bond diamond grinding wheel composites were successfully prepared by gel casting (GC) with 3D printing molds. The effects of different solid content on the properties of vitrified bond/diamond abrasive slurry were researched in this study. The results show that when the solid content was 54 vol%, the green sample had a better flexural strength of about 13 MPa. After the sample was sintered at 760 °C, the relative density and flexural strength of sintered samples was about 80.0% and 78 MPa, respectively. The grinding ratio of the vitrified bond diamond grinding wheel composites prepared by gel casting with 3D printing molds was 1:152, and the removal rate was 2.92 g/min, which means that the performance of the diamond grinding wheel reached the traditional cold pressed sample.

Effects of Sintering Parameters and WC Addition on Properties of Iron-Nickel Pre-Alloy Matrix Diamond Composites

The impregnated diamond composites are widely used for rock drilling and the processing of construction materials. In order to decrease the sintering temperature so as to reduce the thermal damage of diamond, and ultimately improve the sharpness of the diamond tool, the iron-nickel pre-alloyed powder sintered specimens and the impregnated diamond composites were prepared by powder metallurgy. The microstructure and phase composition of specimens were characterized by SEM and EDS. The effect of sintering temperature and the content of WC particles on the mechanical properties of the specimens, such as relative density, hardness, bending strength and wear resistance were investigated. The results showed that the relative density, hardness and bending strength of the sintered specimens increased first and then decreased with the sintering temperature changing from 700 °C to 900 °C. The performance of the specimens sintered at 800 °C was the best, with the corresponding values of 97.75%, 24.0 HRC and 2114.87 MPa. The optimum content of WC was 30wt%, and the grinding ratio reached to 424.11. The rate of penetration of drilling bits with iron-nickel pre-alloyed based matrix increased by 91.14% compared with the traditional bits which used 663Cu-Co-Ni-Mn as binder.

An investigation on machined surface quality and tool wear during creep feed grinding of powder metallurgy nickel-based superalloy FGH96 with alumina abrasive wheels

In this study, the machined surface quality of powder metallurgy nickel-based superalloy FGH96 (similar to Rene88DT) and the grinding characteristics of brown alumina (BA) and microcrystalline alumina (MA) abrasive wheels were comparatively analyzed during creep feed grinding. The influences of the grinding parameters (abrasive wheel speed, workpiece infeed speed, and depth of cut) on the grinding force, grinding temperature, surface roughness, surface morphology, tool wear, and grinding ratio were analyzed comprehensively. The experimental results showed that there was no significant difference in terms of the machined surface quality and grinding characteristics of FGH96 during grinding with the two types of abrasive wheels. This was mainly because the grinding advantages of the MA wheel were weakened for the difficult-to-cut FGH96 material. Moreover, both the BA and MA abrasive wheels exhibited severe tool wear in the form of wheel clogging and workpiece material adhesion. Finally, an analytical model for prediction of the grinding ratio was established by combining the tool wear volume, grinding force, and grinding length. The acceptable errors between the predicted and experimental grinding ratios (ranging from 0.6 to 1.8) were 7.56% and 6.31% for the BA and MA abrasive wheels, respectively. This model can be used to evaluate quantitatively the grinding performance of an alumina abrasive wheel, and is therefore helpful for optimizing the grinding parameters in the creep feed grinding process.

ANALISIS KARAKTERISASI SERBUK BIOKERAMIK DARI CANGKANG TELUR AYAM BROILER

The research is about analysis of Nano Sized Bioceramic Characterization Using Particle Size Analyzer (PSA). In the previous research, optimization of the parameters of making nano powders on Ball Mill machines using the Taguchi and ANOVA methods. The optimum parameters of the Taguchi Design analysis were grinding rate, grinding time and Ball Powder Ratio respectively 250 rpm, 3 hours and 1: 6. After that the characterization of the powder use a Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). Powder size measurement use SEM tools obtained the smallest average size of 1.305 mm while using TEM tools showed the average size of the smallest powder between 50-100 nm. TEM test results were confirmed again using PSA. The results of the characterization using PSA showed that the particle size in the range 100-300 nm was approximately 80%

New approach for cooling and lubrication in dry machining on the example of internal cylindrical grinding of bearing rings

This paper describes a new method of hybrid cooling and lubrication of the machining zone conducted in dry conditions on the example of internal cylindrical grinding of bearing rings. The idea of the method consists in simultaneous application of a cooling agent in the form of compressed cooled air generated by the cold air gun (CAG) nozzle and a solid antiadhesive and lubricating agent fed to the grinding zone in the form of an impregnate in grinding wheel. Hexagonal boron nitride hBN was used as impregnate. The method of hybrid supply of cooling and lubricating agents configured in such a way allows for dry machining process (without the use of liquid coolants), simultaneously performing the cooling and lubricating functions of liquid coolants in a different, more environmentally friendly form. The article presents the characteristics of a new hybrid method of cooling and lubrication of the machining zone, the results of simulation studies on the flow of compressed cooled air (CCA) and heat exchange in the grinding zone, as well as the results of experimental studies on the process of internal cylindrical grinding of 100Cr6 steel bearing rings using the described method. The conducted simulation tests made it possible to determine the most advantageous conditions of feeding the CCA stream into the grinding zone by means of a two outlet supply line for effective cooling of the grinding zone. The most important result of the experimental research was to demonstrate the possibility of five times longer wheel life in the dry grinding process by using the proposed hybrid method of cooling and lubricating in relation to grinding with a non-impregnated wheel without the application of cooling and lubricating agents. The application of the proposed hybrid method of cooling and lubrication significantly reduced the grinding wheel volumetric wear Vs and made it possible to carry out the machining in stable conditions with more than 4 times higher value of grinding ratio G. Proposed method show its advantages also in relation to workpiece and grinding wheel temperature as well as reduction of grinding wheel cloggings.

Characterisation of the wear properties of a single-aggregated cubic boron nitride grain during Ti–6Al–4V alloy grinding

Single-grain grinding the Ti–6Al–4V alloys is performed to investigate the wear characteristics and material removal mechanism of aggregated cubic boron nitride (AcBN) grains fabricated by multiple monocrystalline cBN grains. An innovative approach entailing the tracking of grains and scratches by using the 3D reconstruction is proposed to investigate accurately the wear characteristics and material removal ability of such grains. Grain wear, which is affected by grinding wheel speed vs and undeformed chip thickness agmax, is characterised. The variations in grinding force and grinding force ratio, volumetric pile-up ratio and volumetric groove removal rate are also studied. Results show that the as-sintered AcBN grains have better self-sharpening ability, higher grinding ratio, and more stable grain wear rate than the McBN grains. In addition, the wear rate of AcBN grains is more sensible in determining the effect of vs compared with the use of agmax. The AcBN grains attained a higher wear volume (nearly thrice the value), a more stable wear rate and a more stable grinding force ratio when vs increases to 120 m/s as opposed to the other smaller vs values regardless of the agmax values.

Effect of grain contents of a single-aggregated cubic boron nitride grain on material removal mechanism during Ti–6Al–4V alloy grinding

Aggregated cubic boron nitride (AcBN) grains were developed by sintering monocrystalline cBN (McBN) grains and inter-abrasive metallic phase. The sintering parameters, including sintering temperature and dwelling time, and volumetric proportions of McBN grains are optimized and correlated with the fracture strength of AcBN grains. Quantitative characterization of the grain and scratches were tracked based on the 3D reconstruction technique to study the grain wear characteristics and material removal ability of AcBN grains. The grinding performance for different AcBN grain types, including grinding force, force ratio, volumetric pile-up ratio and volumetric groove removal rate were investigated. Experimental results indicate that the optimized sintering parameters are 800 °C with a dwelling time of 10 min. The AcBN grains with 90% volumetric proportion of McBN grains possess the more stable grinding force ratio and grain wear rate, better self-sharpening ability, and higher grinding ratio. In addition, the material removal efficiency tends to decline and then increase due to the self-sharpening characteristics through the analysis of the volumetric pile-up ratio regardless of AcBN grain types.

PARAMETRIC ANALYSIS OF A GRINDING PROCESS USING THE ROUGH SETS THEORY

With continuous automation of the manufacturing industries and the development of advanced data acquisition systems, a huge volume of manufacturing-related data is now available which can be effectively mined to extract valuable knowledge and unfold the hidden patterns. In this paper, a data mining tool, in the form of the rough sets theory, is applied to a grinding process to investigate the effects of its various input parameters on the responses. Rotational speed of the grinding wheel, depth of cut and type of the cutting fluid are grinding parameters, and average surface roughness, amplitude of vibration and grinding ratio are the responses. The best parametric settings of the grinding parameters are also derived to control the quality characteristics of the ground components. The developed decision rules are quite easy to understand and can truly predict the response values at varying combinations of the considered grinding parameters.

Microstructure and mechanical properties of Fe-ZTA cermet prepared by vacuum hot-pressed sintering

The cermet based on metallic iron with zirconia toughened alumina (ZTA) as the reinforcing phase was prepared by vacuum hot-pressed sintering. The ZTA particles were subjected to electroless nickel plating to improve the interfacial bonding ability of ZTA and Fe matrix. In this paper, after electroless nickel plating, the effects of different particle sizes and different contents of ZTA particles on the grinding properties of Fe-based ZTA (Fe-ZTA) cermets were investigated. The results show that the ZTA particles are tightly bound to the Fe matrix. An interface layer is formed between the ZTA particles and the Fe matrix and it can improve the grinding ability of the Fe-ZTA cermet. By reducing the particle size and the content of ZTA particles, the friction coefficient between Fe-based ZTA cermet and the machined surface can be increased, and the surface roughness of the machined surface will reduce. When the ZTA particle size is F14 and the iron binder content is 40%, the friction coefficient between the Fe-ZTA cermet and the steel bar is 0.4981, the surface roughness of steel bar is 40.164 μm, the grinding ratio is 685.952.

Exploring grindability of Ti-6Al-4V using an indigenously developed environment friendly micro pump based cooling system

Titanium alloys are ideally suited for different manufacturing applications because of their unique combination of highspecific strength over a wide range of temperature, in addition to excellent corrosion resistance properties. However,grinding of titanium alloys is quite difficult due to their high hardness at elevated temperature, low thermal conductivity andelastic modulus. Application of cutting fluid helps to improve grindability, but with the increasing level of environmentalconsciousness, new technologies have been required to address the problem. This investigation deals with application ofalkaline soap water through an indigenously developed micro pump based cooling system during grinding of Ti-6Al-4V.Comparison has been made with dry grinding with respect to some response parameters such as grinding forces, specificenergy, surface roughness, grinding chips and ground surface morphology. Results have indicated that grinding forces,specific energy requirement and surface roughness decrease with the application of the micro pump based system.Observation of grinding ratio, chip form and ground surface has shown favourable results. Therefore, this newly developedmicro pump system may be recommended to supply soap water for grinding titanium alloys.