Effect of Types of Grinding Fluid on Grinding Characteristics of CMSX4

Nickel-based heat-resistant alloys are widely used for fabricating the turbine blades in gas turbine engines. An increase in the number of such engines operated by air carriers will increase the demand for high-efficiency machining of nickel-based heat-resistant alloys. However, the high-efficiency grinding of nickel-based heat-resistant alloys is challenging because of their low thermal conductivity and thermal diffusivity, high chemical activity, large work-hardening properties, and high-temperature strength. In this work, the authors propose a high-efficiency grinding technique that uses speed-stroke grinding of nickel-based heat-resistant alloys, and aim to clarify the optimum grinding conditions for the proposed grinding method. The workpiece material is CMSX4 used for the turbine blades. A Cubitron + WA grinding wheel and WA grinding wheel mounted on a linear motor-driven surface grind machines are used for grinding, and the grinding force, surface roughness, and grinding ratio are investigated with the removal rate maintained constant. Two types of grinding fluid are prepared: solution and soluble. From the experiments, it is found that wet grinding features a lower grinding force, smaller surface roughness, and higher grinding ratio when compared to dry-cut grinding. The improvement in the grinding ratio at high table speeds is significant, and it is found to be greater for the soluble-type fluid than for the solution-type fluid.

Influence of the Material Properties on Microgrooving u sing Wire Tools Electrodeposited with Diamond Grains

In this study, the main objective is to clarify the relationship between the material properties of the work material and the grooving properties for various work materials from hard and brittle materials to metallic materials. In this paper, in order to investigate the grinding characteristics of diamond electroplated wire tools, including the wear characteristics, we conducted grooving experiments with borosilicate glass (Pyrex), which is a kind of hard and brittle material, and aluminum alloy (A5052), and tough pitch copper (C1100), a kind of metallic material, using diamond electroplated wire tools in a work material rotation method. As a result of the grooving experiments, it was clarified that the grooving characteristics of the work materials were influenced by the hardness and brittle behavior of the materials. The groove depth is influenced by the hardness and brittleness behavior of the material. When machining hard materials, the groove depth increases slowly in the initial stage of machining due to the poor bite of the wire tool, but increases rapidly as the machining progresses. On the other hand, the groove width does not depend on the machining time or speed, but is influenced by the hardness of the material and the ease with which plastic deformation occurs. The wear of the wire tool is also influenced by the hardness and brittleness of the material. In the machining of hard materials, the wear caused by stray wire and vibration in the early stages of machining was significant. The grinding ratio calculated from the ratio of the groove depth to the amount of grinding has a very different trend for hard and brittle materials and metallic materials. In the machining of hard and brittle materials, the amount of machining increased rapidly as machining progressed, so the grinding ratio also increased, but in metallic materials, the amount of machining itself was small and the grinding ratio did not increase. For A5052, the grinding ratio tended to decrease as machining progressed. Future work In the future, it is necessary to clarify the machining conditions to reduce the wear caused by stray wire tools and vibration during the initial machining of hard materials.

Experimental Investigation of Wearing Grinding Wheels After Machining Sintered Carbide

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.

Effect of Deep Cryogenic Treatment on Microstructure and Properties of Sintered Fe–Co–Cu-Based Diamond Composites

Metal-matrix-impregnated diamond composites are used for fabricating many kinds of diamond tools. In the efforts to satisfy the increasing engineering requirements, researchers have brought more attention to find novel methods of enhancing the performance of impregnated diamond composites. In this study, deep cryogenic treatment was applied to Fe–Co–Cu-based diamond composites to improve their performance. Relative density, hardness, bending strength, and grinding ratio of matrix and diamond composite samples were measured by a series of tests. Meanwhile, the fracture morphologies of all samples after the bending strength test were observed and analyzed by scanning electron microscope. The results showed that the hardness and bending strength of matrix increased slightly after deep cryogenic treatment. The grinding ratio of impregnated diamond composites exhibited a great increase by 32.9% as a result of deep cryogenic treatment. The strengthening mechanism was analyzed in detail. The Fe–Co–Cu-based impregnated composites subjected to deep cryogenic treatment for 1 h exhibited the best overall performance.

Study on the Cutting Properties of the Singer Layer Metal Bonded cBN Grinding Wheel by Electroplating in Grinding of Heat-Treated Steel SKD11

This article presents preliminary investigations on the cutting ability of the singer layer metal-bonded cBN grinding wheel manufactured by electroplating method at Vietnamese laboratory. The cutting ability of the grinding wheel is evaluated by two factors: grinding ratio G and surface roughness of workpiece. These results are compared to those of the Japanese grinding wheels. The experimental results showed that the fabricated cBN grinding wheel has good cutting ability with high grinding ratio G. The value of the grinding ratio was 600 to 1800 in the grinding process of SKD11 steel (hardness of 62-63HRC) at the grinding speed V of 12.56m/s, feed rate S of 300mm/min, depth of cut t of 0.01mm. The maximum grinding ratio (1800) is equivalent to the average grinding ratio of the Japanese grinding wheel. The grinding ratio is also maintained up to 26 cutting hours. The good grinding surface was achieved with the average Ra of 2.5μm. In addition, the bonding of cBN abrasive to the wheel body was observed with scanning electron microscope (SEM) of the surface of grinding wheel after the cutting process. The SEM image shown that the cBN abrasive particles were not removed from the wheel surface.

Effects of Grinding Passes and Direction on Material Removal Behaviours in the Rail Grinding Process

A three-dimensional finite element model of rail grinding was established to explore the effects of grinding passes and grinding direction on the material removal behaviour of grinding rails during the grinding process. The results indicate that as the number of grinding passes increases, a decrease in the grinding force reduces both the amount of removed rail material and the surface roughness. There is a decrease in the grinding ratio caused by the increase in the wear on the grinding wheel and the decreased removal of the rail material. When the grinding direction changes, the wear of the grinding wheel decreases, which is contrary to the increasing trend of the amount of removed rail material, the grinding ratio, the surface roughness and the grinding force.

Effect of WC Nanoparticles on the Microstructure and Properties of WC-Bronze-Ni-Mn Based Diamond Composites

Metal matrix-impregnated diamond composites are widely used for fabricating diamond tools. In order to meet the actual engineering challenges, researchers have made many efforts to seek effective methods to enhance the performance of conventional metal matrices. In this work, tungsten carbide (WC) nanoparticles were introduced into WC-Bronze-Ni-Mn matrix with and without diamond grits for improving the performance of conventional impregnated diamond composites. The influence of WC nanoparticles on the microstructure, densification, hardness, bending strength and wear resistance of matrix and diamond composites were investigated. The results showed that the bending strength of matrix increased up to approximately 20% upon nano-WC addition, while densification and hardness fluctuate slightly. The grinding ratio of diamond composites increased significantly by about 100% due to nano-WC addition. The strengthening mechanism was proposed according to experimental results. The diamond composites with 2.8 wt% nano-WC addition exhibited the best overall properties, thus having potential to apply to further diamond tools.