The undeformed chip thickness and grinding force are key parameters for revealing the material removal mechanism in the grinding process.However,they are difficult to be well expressed due to the ununiformed protrusio...The undeformed chip thickness and grinding force are key parameters for revealing the material removal mechanism in the grinding process.However,they are difficult to be well expressed due to the ununiformed protrusion height and random position distribution of abrasive grains on the abrasive wheel surface.This study investigated the distribution of undeformed chip thickness and grinding force considering the non-uniform characteristics of abrasive wheel in the grinding of K4002 nickel-based superalloy.First,a novel grinding force model was established through a kinematic-geometric analysis and a grain-workpiece contact analysis.Then,a series of grinding experiments were conducted for verifying the model.The results indicate that the distribution of undeformed chip thickness is highly consistent with the Gaussian distribution formula.The increase in the grinding depth mainly leads to an increase in the average value of Gaussian distribution.On the contrary,the increase in the workpiece infeed speed or the decrease in the grinding speed mainly increases the standard deviation of Gaussian distribution.The average and maximum errors of the grinding force model are 4.9%and 14.6%respectively,indicating that the model is of high predication accuracy.展开更多
High machining precision and machining efficiency can be obtained in grinding WC-Co coating by cup wheel. The conventional model of the grinding force is not suitable for the grinding of the cup wheel due to the diffe...High machining precision and machining efficiency can be obtained in grinding WC-Co coating by cup wheel. The conventional model of the grinding force is not suitable for the grinding of the cup wheel due to the difference in grinding style between the cup wheel and the conventional external wheel. So the grit grinding process of the cup wheel is studied, and a new concept of the effective grinding width of the cup wheel is presented. Then the grinding force in grinding WC-Co coating materials by cup wheel is analyzed and a theoretical formula is deduced. Finally, experimental results of the grinding force verify the correctness and the precision of the theoretical formula.展开更多
As is known to all, grinding force is one of the most important parameters to evaluate the whole process of grinding. Generally, the grinding force is resolved to three component forces, namely, normal grinding force ...As is known to all, grinding force is one of the most important parameters to evaluate the whole process of grinding. Generally, the grinding force is resolved to three component forces, namely, normal grinding force F n, tangential grinding force F t and a component force acting along the direction of longitudinal feed which is usually neglected because of insignificance. The normal grinding force F n has influence upon surface deformation and roughness of workpiece, while the tangential grinding force F t mainly affect power consumption and service life of grinding wheel. In order to study deep into the process of the unsteady state grinding, we set up a measurement system to monitor the change of grinding force during the course of grinding and try to find some difference in the change of grinding force between the steady state grinding and unsteady state grinding. In the test, the normal and tangential grinding forces, F n and F t were measured by using a set of equipments including sensor, amplifier, oscilloscope and computer monitor. From the results, we can conclude that: 1) In the unsteady state grinding process, the values of the grinding forces are much lower than those of the steady state grinding process and the grinding force ratio showed a nonlinear fluctuation. 2) The tendency of the grinding forces in the process of the unsteady state grinding proved the existence of the cutting and micro-cutting actions. 3) Because the grinding force signals of the unsteady state grinding are much weaker than those of the steady state grinding, to obtain accurate value of the grinding forces, wave filtering is needed to be done. The whole process to filter the perturbation wave can be separated into three steps in order, changing the grinding force signals from analog signals into digital signals, FFT (fast Fourier transform) treatment to the digital signals, and IFFT(inversion fast Fourier transform) treatment to the digital signals after spectrum limitation.展开更多
Too high grinding force will lead to a large increase in specific grinding energy, resulting in high temperature in grinding zone, especially for the aerospace difficult cutting metal materials,seriously affecting the...Too high grinding force will lead to a large increase in specific grinding energy, resulting in high temperature in grinding zone, especially for the aerospace difficult cutting metal materials,seriously affecting the surface quality and accuracy. At present, the theoretical models of grinding force are mostly based on the assumption of uniform or simplified morphological characteristics of grains, which is inconsistent with the actual grains. Especially for non-engineering grinding wheel,most geometric characteristics of grains are ignored, resulting in the calculation accuracy that cannot guide practical production. Based on this, an improved grinding force model based on random grain geometric characteristics is proposed in this paper. Firstly, the surface topography model of CBN grinding wheel is established, and the effective grain determination mechanism in grinding zone is revealed. Based on the known grinding force model and mechanical behavior of interaction between grains and workpiece in different stages, the concept of grain effective action area is proposed. The variation mechanism of effective action area under the influence of grain geometric and spatial characteristics is deeply analyzed, and the calculation method under random combination of five influencing parameters is obtained. The numerical simulation is carried out to reveal the dynamic variation process of grinding force in grinding zone. In order to verify the theoretical model, the experiments of dry grinding Ti-6Al-4 V are designed. The experimental results show that under different machining parameters, the results of numerical calculation and experimental measurement are in good agreement, and the minimum error value is only 2.1 %, which indicates that the calculation accuracy of grinding force model meets the requirements and is feasible. This study will provide a theoretical basis for optimizing the wheel structure, effectively controlling the grinding force range, adjusting the grinding zone temperature and improving the workpiece machining quality in the industrial grinding process.展开更多
Creep feed profile grinding of the fir-tree blade root forms of single crystal nickel-based superalloy was conducted using microcrystalline alumina abrasive wheels in the present study. The grinding force and the surf...Creep feed profile grinding of the fir-tree blade root forms of single crystal nickel-based superalloy was conducted using microcrystalline alumina abrasive wheels in the present study. The grinding force and the surface quality in terms of surface topography, subsurface microstructure,microhardness and residual stress obtained under different grinding conditions were evaluated comparatively. Experimental results indicated that the grinding force was influenced significantly by the competing predominance between the grinding parameters and the cross-sectional root workpiece profile. In addition, the root workpiece surface, including the root peak and valley regions, was produced with the large difference in surface quality due to the nonuniform grinding loads along the root workpiece profile in normal section. Detailed results showed that the surface roughness, subsurface plastic deformation and work hardening level of the root valley region were higher by up to25%, 20% and 7% in average than those obtained in the root peak region, respectively, in the current investigation. Finally, the superior parameters were recommended in the creep feed profile grinding of the fir-tree blade root forms. This study is helpful to provide industry guidance to optimize the machining process for the high-valued parts with complicated profiles.展开更多
In this article,a grinding force model,which is on the basis of cutting process of single abrasive grains combined with the method of theoretical derivation and empirical formula by analyzing the formation mechanism o...In this article,a grinding force model,which is on the basis of cutting process of single abrasive grains combined with the method of theoretical derivation and empirical formula by analyzing the formation mechanism of grinding force,was established.Three key factors have been taken into accounts in this model,such as the contact friction force between abrasive grains and materials,the plastic deformation of material in the process of abrasive plowing,and the shear strain effect of material during the process of cutting chips formation.The model was finally validated by the orthogonal grinding experiment of powder metallurgy nickel-based superalloy FGH96 by using the electroplated CBN abrasive wheel.Grinding force values of prediction and experiment were in good consistency.The errors of tangential grinding force and normal grinding force were 9.8%and 13.6%,respectively.The contributions of sliding force,plowing force and chip formation force were also analyzed.In addition,the tangential forces of sliding,plowing and chip formation are 14%,19%and 11%of the normal forces on average,respectively.The pro-posed grinding forcemodel is not only in favor of optimizing the grinding parameters and improving grinding efficiency,but also contributes to study some other grinding subjects(e.g.abrasive wheel wear,grinding heat,residual stress).展开更多
The ability to predict a grinding force is important to control,monitor,and optimize the grinding process.Few theoretical models were developed to predict grinding forces when a structured wheel was used in a grinding...The ability to predict a grinding force is important to control,monitor,and optimize the grinding process.Few theoretical models were developed to predict grinding forces when a structured wheel was used in a grinding process.This paper aimed to establish a single-grit cutting force model to predict the ploughing,friction and cutting forces in a grinding process.It took into the consideration of actual topography of the grinding wheel,and a theoretical grinding force model for grinding hardened AISI 52100 by the wheel with orderly-micro-grooves was proposed.The model was innovative in the sense that it represented the random thickness of undeformed chips by a probabilistic expression,and it reflected the microstructure characteristics of the structured wheel explicitly.Note that the microstructure depended on the randomness of the protruding heights and distribution density of the grits over the wheel.The proposed force prediction model was validated by surface grinding experiments,and the results showed(1)a good agreement of the predicted and measured forces and(2)a good agreement of the changes of the grinding forces along with the changes of grinding parameters in the prediction model and experiments.This research proposed a theoretical grinding force model of an electroplated grinding wheel with orderly-micro-grooves which is accurate,reliable and effective in predicting grinding forces.展开更多
The grind-hardening method suitable for external grinding is proposed in this paper and the experiments are carried out on M1432B grinding machine. The hardened layer of the workpiece with cut depth 0.3 mm and speed 0...The grind-hardening method suitable for external grinding is proposed in this paper and the experiments are carried out on M1432B grinding machine. The hardened layer of the workpiece with cut depth 0.3 mm and speed 0.2 m/min is analyzed. The result indicates the metallurgical structure of the hardened layer is martensite and the top hardness value is 754 HV （about 62.3 HRC）. At the same time, the grinding force, one of the most important factors of external grind-hardening process is modeled, and the measurement method is provided with elastic core clampers. The measurement result shows that the values of both the tangential force and the normal force increase when the cut depth increases, and the top value is 146 N and 656 N with the cut depth value of 0.4 mm. The increment speed and the value of the normal force are larger than the tangential force.展开更多
The force of grinding particle was disintegrated to study the physical and mathematical models. The grinding wheel can be characterized by grinding ratio, C, a steady constant. The moment and C of grinding wheel can b...The force of grinding particle was disintegrated to study the physical and mathematical models. The grinding wheel can be characterized by grinding ratio, C, a steady constant. The moment and C of grinding wheel can be estimated with electrical parameters. The grinding force can be calculated quite easily in this way.展开更多
In order to deal with the hard machining of TC4 alloy,coated graphite on grinding wheel surface by electrostatic device is proposed in this paper.This paper mainly completed the design of graphite electrostatic sprayi...In order to deal with the hard machining of TC4 alloy,coated graphite on grinding wheel surface by electrostatic device is proposed in this paper.This paper mainly completed the design of graphite electrostatic spraying grinding wheel device,force experimental analysis of grinding TC4 alloy with coated graphite grinding wheel,and summary of the influence of different grinding speeds and grinding depths on grinding force and grinding force ratio.The experimental results show that the lubrication coating can reduce the grinding force and grinding force ratio in the process of grinding TC4 alloy with graphite powder-coated wheel under electrostatic field force,compared to dry grinding with the uncoated wheel.展开更多
During the grinding train operation process,the grinding force between the grinding wheel and the rail is critical in ensuring the grinding quality and efficiency.The coupling vibration among the frame,the grinding wh...During the grinding train operation process,the grinding force between the grinding wheel and the rail is critical in ensuring the grinding quality and efficiency.The coupling vibration among the frame,the grinding wheels,and the wheelsets will seriously affect the stability of the grinding force.In this paper,the coupled mechanical model of the grinding wheel/rail is established based on the contact mechanics theory,which is embedded as a submodel into the dynamic model of the multi-rigid buggy.The interaction among the frame,the grinding wheels and the wheelsets is analysed by setting the convex irregularity on the rail.The grinding effect is evaluated in combination with the subway’s long wave corrugation grinding conditions.The results show that when the grinding buggy passes the convex irregularity,the vibration excited by the wheelset system has a significant impact on the dynamic behavior of the grinding wheels.The vibration of the grinding wheel is mainly transmitted between the grinding wheel and the frame,less affecting the wheelset.For the long wave corrugation of the subway,the grinding effect of the grinding wheel has a certain correlation with the phase angle of the wheelset through the corrugation.The research results provide an important reference for the setting of the grinding pattern.展开更多
SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant dispari...SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant disparity in properties between SiC particles and the aluminum matrix results in severe tool wear and diminished surface quality during conventional machining.This study proposes an environmentally friendly and clean dry electrical discharge assisted grinding process as an efficient and low-damage machining method for SiCp/Al.An experimental platform was set up to study the impact of grinding and discharge process parameters on surface quality.The study compared the chip formation mechanism and surface quality between dry electrical discharge assisted grinding and conventional grinding,revealing relationships between surface roughness,grinding force,grinding temperature,and related parameters.The results indicate that the proposed grinding method leads to smaller chip sizes,lower grinding forces and temperatures,and an average reduction of 19.2%in surface roughness compared to conventional grinding.The axial,tangential,and normal grinding forces were reduced by roughly 10.5%,37.8%,and 23.0%,respectively.The optimized process parameters were determined to be N=2500 r/min,vf=30 mm/min,a=10μm,E=15 V,f=5000 Hz,dc=80%,resulting in a surface roughness of 0.161μm.展开更多
Gamma titanium-aluminum intermetallic compounds(γ-TiAl)have gained considerable attentions in the aerospace industry due to their exceptional thermal resilience and comprehensive attributes,making them a prime exampl...Gamma titanium-aluminum intermetallic compounds(γ-TiAl)have gained considerable attentions in the aerospace industry due to their exceptional thermal resilience and comprehensive attributes,making them a prime example of lightweight and advanced materials.To address the frequent occurrence of burns and severe tool deterioration during the process of high-efficiency deep grinding(HEDG)onγ-TiAl alloys,ultrasonic vibration-assisted high-efficiency deep grinding(UVHEDG)has been emerged.Results indicate that in UVHEDG,the grinding temperature is on average 15.4%lower than HEDG due to the employment of ultrasonic vibrations,enhancing coolant penetration into the grinding area and thus reducing heat generation.Besides,UVHEDG possesses superior performance in terms of grinding forces compared to HEDG.As the material removal volume(MRV)increases,the tangential grinding force(F_(t))and normal grinding force(F_(n))of UVHEDG increase but to a lesser extent than in HEDG,with an average reduction of16.25%and 14.7%,respectively.UVHEDG primarily experiences microfracture of grains,whereas HEDG undergoes large-scale wear later in the process due to increased grinding forces.The surface roughness(R_(a))characteristics of UVHEDG are superior,with the average value of R_(a)decreasing by 46.5%compared to HEDG as MRV increases.The surface morphology in UVHEDG exhibits enhanced smoothness and a shallower layer of plastic deformation.Grinding chips generated by UVHEDG show a more shear-like shape,with the applied influence of ultrasonic vibration on chip morphology,thereby impacting material removal behaviors.These aforementioned findings contribute to enhanced machining efficiency and product quality ofγ-TiAl alloys after employing ultrasonic vibrations into HEDG.展开更多
Recent research on the grinding force involved in cylindrical plunge grinding has focused mainly on steady-state conditions.Unlike in conventional external cylindrical plunge grinding,the conditions between the grindi...Recent research on the grinding force involved in cylindrical plunge grinding has focused mainly on steady-state conditions.Unlike in conventional external cylindrical plunge grinding,the conditions between the grinding wheel and the crankpin change periodically in path controlled grinding because of the eccentricity of the crankpin and the constant rotational speed of the crankshaft.The objective of this study is to investigate the effects of various grinding conditions on the characteristics of the grinding force during continuous path controlled grinding.Path controlled plunge grinding is conducted at a constant rotational speed using a cubic boron nitride（CBN）wheel.The grinding force is determined by measuring the torque.The experimental results show that the force and torque vary sinusoidally during dry grinding and load grinding.The variations in the results reveal that the resultant grinding force and torque decrease with higher grinding speeds and increase with higher peripheral speeds of the pin and higher grinding depths.In path controlled grinding,unlike in conventional external cylindrical plunge grinding,the axial grinding force cannot be disregarded.The speeds and speed ratios of the workpiece and wheel are also analyzed,and the analysis results show that up-grinding and down-grinding occur during the grinding process.This paper proposes a method for describing the force behavior under varied process conditions during continuous path controlled grinding,which provides a beneficial reference for describing the material removal mechanism and for optimizing continuous controlled crankpin grinding.展开更多
Vegetable oil can be used as a base oil in minimal quantity of lubrication (MQL). This study compared the performances of MQL grinding by using castor oil, soybean oil, rapeseed oil, corn oil, sunflower oil, peanut oi...Vegetable oil can be used as a base oil in minimal quantity of lubrication (MQL). This study compared the performances of MQL grinding by using castor oil, soybean oil, rapeseed oil, corn oil, sunflower oil, peanut oil, and palm oil as base oils. A K-P36 numerical-control precision surface grinder was used to perform plain grinding on a workpiece material with a high-temperature nickel base alloy. A YDM-III 99 three-dimensional dynamometer was used to measure grinding force, and a clip-type thermocouple was used to determine grinding temperature. The grinding force, grinding temperature, and energy ratio coefficient of MQL grinding were compared among the seven vegetable oil types. Results revealed that (1) castor oil-based MQL grinding yields the lowest grinding force but exhibits the highest grinding temperature and energy ratio coefficient; (2) palm oil-based MQL grinding generates the second lowest grinding force but shows the lowest grinding temperature and energy ratio coefficient; (3) MQL grinding based on the five other vegetable oils produces similar grinding forces, grinding temperatures, and energy ratio coefficients, with values ranging between those of castor oil and palm oil; (4) viscosity significantly influences grinding force and grinding temperature to a greater extent than fatty acid varieties and contents in vegetable oils; (5) although more viscous vegetable oil exhibits greater lubrication and significantly lower grinding force than less viscous vegetable oil, high viscosity reduces the heat exchange capability of vegetable oil and thus yields a high grinding temperature; (6) saturated fatty acid is a more efficient lubricant than unsaturated fatty acid; and (7) a short carbon chain transfers heat more effectively than a long carbon chain. Palm oil is the optimum base oil of MQL grinding, and this base oil yields 26.98 N tangential grinding force, 87.10 N normal grinding force, 119.6 degrees C grinding temperature, and 42.7% energy ratio coefficient. (C) 2015 The Authors. Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.展开更多
Single grit grinding is the simplified model to abstract the macro scale grinding.Finite element analysis is a strong tool to study the physical fields during a single grit grinding process,compared to experimental re...Single grit grinding is the simplified model to abstract the macro scale grinding.Finite element analysis is a strong tool to study the physical fields during a single grit grinding process,compared to experimental research.Based on the dynamic mechanical behavior of 2Cr12Ni4Mo3VNbN steel and the mathematical statistics of abrasive grit,modeling of the single grit grinding process was conducted by using commercial software AdvantEdge.The validation experiment was designed to validate the correctness of the FEA model by contrast with grinding force.The validation result shows that the FEA model can well describe the single grit grinding process.Then the grinding force and multi-physics fields were studied by experimental and simulation results.It was found that both the normal and tangential grinding forces were linearly related to the cutting speed and cutting depth.The maximum temperature is located in the subsurface of the workpiece in front of the grit,while the maximum stress and strain are located under the grit tip.The strain rate can reach as high as about 106 s–1 during the single grit grinding,which is larger than other traditional machining operations.展开更多
The purpose of this study is to investigate the effect of graphite lubricant on the dry grinding performance of Ti-6Al-4Valloy,using graphite-coated,brazed monolayer,cubic boron nitride(cBN)wheels.Brazed monolayer cBN...The purpose of this study is to investigate the effect of graphite lubricant on the dry grinding performance of Ti-6Al-4Valloy,using graphite-coated,brazed monolayer,cubic boron nitride(cBN)wheels.Brazed monolayer cBN wheels both with and without a coating of polymer-based graphite lubricant are fabricated and subsequently compared for grinding performance based on measurements of grinding temperature,surface microstructure and grinding.In terms of grinding temperature,considerable improvement in dry grinding performance of titanium alloy is achieved using coated brazed monolayer cBN wheels,with 42%—47%reduction in grinding temperature as opposed to uncoated wheels.The grinding force ratio with the coated wheels is observed to remain between 1.45to1.85despite material removal rates reaching up to 1 950mm3/mm.No tangible change in ground titanium surface microstructure is noted as a result of grinding with the graphite coated wheels as opposed to the uncoated ones.展开更多
Particle-reinforcing titanium matrix composites(PTMCs)exhibit the sharp raising applications in modern industries owing to its extraordinary physical and mechanical properties.However,the poor grindability and unstabl...Particle-reinforcing titanium matrix composites(PTMCs)exhibit the sharp raising applications in modern industries owing to its extraordinary physical and mechanical properties.However,the poor grindability and unstable grinding processes due to the existence of TiC particles and TiB short fibres inside PTMCs,leading to the sudden grinding burn and low material removal rate.In this work,a novel radial ultrasonic vibration-assisted grinding(RUVAG)device with a special cross structure was developed to improve machining efficiency and avoid grinding burns.Meanwhile,the resonant modal and transient dynamic characteristics of radial ultrasonic vibration system were discussed.Comparative grinding performance experiments were then conducted under the conventional grinding(CG)and RUVAG using mono-layer cubic boron nitride abrasive wheels,in views of the grinding forces and force ratio,grinding temperature,and ground surface morphology.Results show that the ultrasonic vibration direction can be transformed effectively using the special cross structure of vibration converter,and better vibration homogeneity can be obtained.RUVAG has a smaller tangential grinding force by 5.0%–17.2%than that of CG,but a higher normal grinding force of 6.5%–14.9%,owing to the periodic impact of grinding wheels.In addition,RUVAG possesses a remarkable lower grinding temperature in range of 24.2%–51.8%and a higher material removal rate by 2.8 times compared with CG,resulting from the intermittent cutting behavior between the grinding wheel and workpiece.In this case,the sudden burn can be avoided during high-speed grinding processes.Moreover,the proportion of micro-fracture defects on machined surface is slightly increased once the ultrasonic vibration mode is employed because of the periodic impact on reinforced particles,whereas the pull-out defects of reinforced particles are reduced significantly.展开更多
（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforc...（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were discussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally beneficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.展开更多
The purpose of this study is to develop a twin wheel creep-feed grinding machine using continuous dressing to machine precise axisymmetric turbine blades that have been difficult to machine using a conventional creep-...The purpose of this study is to develop a twin wheel creep-feed grinding machine using continuous dressing to machine precise axisymmetric turbine blades that have been difficult to machine using a conventional creep-feed machine.In order to develop such a machine,3D-modeling and machine simulations were performed and a twin wheel creep-feed grinding machine was manufactured.Furthermore,the axisymmetric precision of the machined workpieces through practical machining was evaluated and the quality of the continuous dressing effect of the developed machine was established.In addition,experimental considerations for a proper dresser-to-wheel speed ratio and proper feed rate of the dresser were carried out.As a result,a twin wheel creep-feed grinding machine with continuous dressing is developed through machine simulation,manufacturing and performance evaluation.Optimum condition for the dresser feed rate is 0.3μm/rev.In cases of large dressor-to-wheel speed ratio,grinding efficiency can be enhanced,but the surface roughness shows a conflicting trend.Developed twin wheel creep-feed grinding machine has satisfactory appraisal with regard to surface roughness,flatness,and parallelism.Satisfactory surface roughness below 0.1μm can be obtained for the blade of aircraft.However,in order to perform precise machining,it is necessary to improve the structure of the twin wheel creep-feed grinding machine.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.92160301,92060203,52175415 and 52205475)the Science Center for Gas Turbine Project(Nos.P2022-AB-Ⅳ-002-001 and P2023-B-Ⅳ-003-001)+3 种基金the Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology(No.JSKL2223K01)the Natural Science Foundation of Jiangsu Province(No.BK20210295)the Superior Postdoctoral Project of Jiangsu Province(No.2022ZB215)the Henan Science and Technology Public Relations Project(No.212102210445).
文摘The undeformed chip thickness and grinding force are key parameters for revealing the material removal mechanism in the grinding process.However,they are difficult to be well expressed due to the ununiformed protrusion height and random position distribution of abrasive grains on the abrasive wheel surface.This study investigated the distribution of undeformed chip thickness and grinding force considering the non-uniform characteristics of abrasive wheel in the grinding of K4002 nickel-based superalloy.First,a novel grinding force model was established through a kinematic-geometric analysis and a grain-workpiece contact analysis.Then,a series of grinding experiments were conducted for verifying the model.The results indicate that the distribution of undeformed chip thickness is highly consistent with the Gaussian distribution formula.The increase in the grinding depth mainly leads to an increase in the average value of Gaussian distribution.On the contrary,the increase in the workpiece infeed speed or the decrease in the grinding speed mainly increases the standard deviation of Gaussian distribution.The average and maximum errors of the grinding force model are 4.9%and 14.6%respectively,indicating that the model is of high predication accuracy.
文摘High machining precision and machining efficiency can be obtained in grinding WC-Co coating by cup wheel. The conventional model of the grinding force is not suitable for the grinding of the cup wheel due to the difference in grinding style between the cup wheel and the conventional external wheel. So the grit grinding process of the cup wheel is studied, and a new concept of the effective grinding width of the cup wheel is presented. Then the grinding force in grinding WC-Co coating materials by cup wheel is analyzed and a theoretical formula is deduced. Finally, experimental results of the grinding force verify the correctness and the precision of the theoretical formula.
文摘As is known to all, grinding force is one of the most important parameters to evaluate the whole process of grinding. Generally, the grinding force is resolved to three component forces, namely, normal grinding force F n, tangential grinding force F t and a component force acting along the direction of longitudinal feed which is usually neglected because of insignificance. The normal grinding force F n has influence upon surface deformation and roughness of workpiece, while the tangential grinding force F t mainly affect power consumption and service life of grinding wheel. In order to study deep into the process of the unsteady state grinding, we set up a measurement system to monitor the change of grinding force during the course of grinding and try to find some difference in the change of grinding force between the steady state grinding and unsteady state grinding. In the test, the normal and tangential grinding forces, F n and F t were measured by using a set of equipments including sensor, amplifier, oscilloscope and computer monitor. From the results, we can conclude that: 1) In the unsteady state grinding process, the values of the grinding forces are much lower than those of the steady state grinding process and the grinding force ratio showed a nonlinear fluctuation. 2) The tendency of the grinding forces in the process of the unsteady state grinding proved the existence of the cutting and micro-cutting actions. 3) Because the grinding force signals of the unsteady state grinding are much weaker than those of the steady state grinding, to obtain accurate value of the grinding forces, wave filtering is needed to be done. The whole process to filter the perturbation wave can be separated into three steps in order, changing the grinding force signals from analog signals into digital signals, FFT (fast Fourier transform) treatment to the digital signals, and IFFT(inversion fast Fourier transform) treatment to the digital signals after spectrum limitation.
基金supported by the National Natural Science Foundation of China(Nos.51975305,51905289,52105264)the Key Project of Shandong Province,China(No.ZR2020KE027)+1 种基金the Major Research Project of Shandong Province,China(Nos.2019GGX104040 and 2019GSF108236)the Natural Science Foundation of Shandong Province,China(No.ZR2021QE116).
文摘Too high grinding force will lead to a large increase in specific grinding energy, resulting in high temperature in grinding zone, especially for the aerospace difficult cutting metal materials,seriously affecting the surface quality and accuracy. At present, the theoretical models of grinding force are mostly based on the assumption of uniform or simplified morphological characteristics of grains, which is inconsistent with the actual grains. Especially for non-engineering grinding wheel,most geometric characteristics of grains are ignored, resulting in the calculation accuracy that cannot guide practical production. Based on this, an improved grinding force model based on random grain geometric characteristics is proposed in this paper. Firstly, the surface topography model of CBN grinding wheel is established, and the effective grain determination mechanism in grinding zone is revealed. Based on the known grinding force model and mechanical behavior of interaction between grains and workpiece in different stages, the concept of grain effective action area is proposed. The variation mechanism of effective action area under the influence of grain geometric and spatial characteristics is deeply analyzed, and the calculation method under random combination of five influencing parameters is obtained. The numerical simulation is carried out to reveal the dynamic variation process of grinding force in grinding zone. In order to verify the theoretical model, the experiments of dry grinding Ti-6Al-4 V are designed. The experimental results show that under different machining parameters, the results of numerical calculation and experimental measurement are in good agreement, and the minimum error value is only 2.1 %, which indicates that the calculation accuracy of grinding force model meets the requirements and is feasible. This study will provide a theoretical basis for optimizing the wheel structure, effectively controlling the grinding force range, adjusting the grinding zone temperature and improving the workpiece machining quality in the industrial grinding process.
基金financial support for this work by the National Natural Science Foundation of China (No. 51775275)the Funding of Jiangsu Innovation Program for Graduate Education of China (KYCX170245)+2 种基金the Funding for Outstanding Doctoral Dissertation in NUAA of China (BCXJ17-04)the Fundamental Research Funds for the Central University of China (No. NP2018110)the National Science and Technology Major Project and the Six Talents Summit Project in Jiangsu Province of China (No.JXQC-002)。
文摘Creep feed profile grinding of the fir-tree blade root forms of single crystal nickel-based superalloy was conducted using microcrystalline alumina abrasive wheels in the present study. The grinding force and the surface quality in terms of surface topography, subsurface microstructure,microhardness and residual stress obtained under different grinding conditions were evaluated comparatively. Experimental results indicated that the grinding force was influenced significantly by the competing predominance between the grinding parameters and the cross-sectional root workpiece profile. In addition, the root workpiece surface, including the root peak and valley regions, was produced with the large difference in surface quality due to the nonuniform grinding loads along the root workpiece profile in normal section. Detailed results showed that the surface roughness, subsurface plastic deformation and work hardening level of the root valley region were higher by up to25%, 20% and 7% in average than those obtained in the root peak region, respectively, in the current investigation. Finally, the superior parameters were recommended in the creep feed profile grinding of the fir-tree blade root forms. This study is helpful to provide industry guidance to optimize the machining process for the high-valued parts with complicated profiles.
基金financial support for this work by the National Natural Science Foundation of China(Nos.51775275,51921003 and 51905363)the Funding for Outstanding Doctoral Dissertation in NUAA of China(No.BCXJ19-06)+1 种基金the Natural Science Foundation of Jiangsu Province of China(No.BK20190940)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.19KJB460008)。
文摘In this article,a grinding force model,which is on the basis of cutting process of single abrasive grains combined with the method of theoretical derivation and empirical formula by analyzing the formation mechanism of grinding force,was established.Three key factors have been taken into accounts in this model,such as the contact friction force between abrasive grains and materials,the plastic deformation of material in the process of abrasive plowing,and the shear strain effect of material during the process of cutting chips formation.The model was finally validated by the orthogonal grinding experiment of powder metallurgy nickel-based superalloy FGH96 by using the electroplated CBN abrasive wheel.Grinding force values of prediction and experiment were in good consistency.The errors of tangential grinding force and normal grinding force were 9.8%and 13.6%,respectively.The contributions of sliding force,plowing force and chip formation force were also analyzed.In addition,the tangential forces of sliding,plowing and chip formation are 14%,19%and 11%of the normal forces on average,respectively.The pro-posed grinding forcemodel is not only in favor of optimizing the grinding parameters and improving grinding efficiency,but also contributes to study some other grinding subjects(e.g.abrasive wheel wear,grinding heat,residual stress).
基金Supported by National Natural Science Foundation of China(Grant Nos.52275405,52275311,51875050)Hunan Provincial Key Research and Development Program(Grant No.2021GK2021).
文摘The ability to predict a grinding force is important to control,monitor,and optimize the grinding process.Few theoretical models were developed to predict grinding forces when a structured wheel was used in a grinding process.This paper aimed to establish a single-grit cutting force model to predict the ploughing,friction and cutting forces in a grinding process.It took into the consideration of actual topography of the grinding wheel,and a theoretical grinding force model for grinding hardened AISI 52100 by the wheel with orderly-micro-grooves was proposed.The model was innovative in the sense that it represented the random thickness of undeformed chips by a probabilistic expression,and it reflected the microstructure characteristics of the structured wheel explicitly.Note that the microstructure depended on the randomness of the protruding heights and distribution density of the grits over the wheel.The proposed force prediction model was validated by surface grinding experiments,and the results showed(1)a good agreement of the predicted and measured forces and(2)a good agreement of the changes of the grinding forces along with the changes of grinding parameters in the prediction model and experiments.This research proposed a theoretical grinding force model of an electroplated grinding wheel with orderly-micro-grooves which is accurate,reliable and effective in predicting grinding forces.
文摘The grind-hardening method suitable for external grinding is proposed in this paper and the experiments are carried out on M1432B grinding machine. The hardened layer of the workpiece with cut depth 0.3 mm and speed 0.2 m/min is analyzed. The result indicates the metallurgical structure of the hardened layer is martensite and the top hardness value is 754 HV （about 62.3 HRC）. At the same time, the grinding force, one of the most important factors of external grind-hardening process is modeled, and the measurement method is provided with elastic core clampers. The measurement result shows that the values of both the tangential force and the normal force increase when the cut depth increases, and the top value is 146 N and 656 N with the cut depth value of 0.4 mm. The increment speed and the value of the normal force are larger than the tangential force.
文摘The force of grinding particle was disintegrated to study the physical and mathematical models. The grinding wheel can be characterized by grinding ratio, C, a steady constant. The moment and C of grinding wheel can be estimated with electrical parameters. The grinding force can be calculated quite easily in this way.
基金National Natural Science Foundation of China(No.51305301)Tianjin Research Program of Application Foundation and Advanced Technology,China(No.14JCQNJC05100)。
文摘In order to deal with the hard machining of TC4 alloy,coated graphite on grinding wheel surface by electrostatic device is proposed in this paper.This paper mainly completed the design of graphite electrostatic spraying grinding wheel device,force experimental analysis of grinding TC4 alloy with coated graphite grinding wheel,and summary of the influence of different grinding speeds and grinding depths on grinding force and grinding force ratio.The experimental results show that the lubrication coating can reduce the grinding force and grinding force ratio in the process of grinding TC4 alloy with graphite powder-coated wheel under electrostatic field force,compared to dry grinding with the uncoated wheel.
基金Supported by National Natural Science Foundation of China(Grant No.52475137)Sichuan Provincial Science and Technology Program(Grant No.2024YFHZ0280)Sichuan Provincial Nature and Science Foundation Innovation Research Group Project(Grant No.2023NSFSC1975).
文摘During the grinding train operation process,the grinding force between the grinding wheel and the rail is critical in ensuring the grinding quality and efficiency.The coupling vibration among the frame,the grinding wheels,and the wheelsets will seriously affect the stability of the grinding force.In this paper,the coupled mechanical model of the grinding wheel/rail is established based on the contact mechanics theory,which is embedded as a submodel into the dynamic model of the multi-rigid buggy.The interaction among the frame,the grinding wheels and the wheelsets is analysed by setting the convex irregularity on the rail.The grinding effect is evaluated in combination with the subway’s long wave corrugation grinding conditions.The results show that when the grinding buggy passes the convex irregularity,the vibration excited by the wheelset system has a significant impact on the dynamic behavior of the grinding wheels.The vibration of the grinding wheel is mainly transmitted between the grinding wheel and the frame,less affecting the wheelset.For the long wave corrugation of the subway,the grinding effect of the grinding wheel has a certain correlation with the phase angle of the wheelset through the corrugation.The research results provide an important reference for the setting of the grinding pattern.
基金Supported by National Natural Science Foundation of China(Grant Nos.52475480,51805334)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515030249,2023A1515110059)Shenzhen Science and Technology Program(Grant No.GJHZ20220913144212023).
文摘SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal toughness.However,the significant disparity in properties between SiC particles and the aluminum matrix results in severe tool wear and diminished surface quality during conventional machining.This study proposes an environmentally friendly and clean dry electrical discharge assisted grinding process as an efficient and low-damage machining method for SiCp/Al.An experimental platform was set up to study the impact of grinding and discharge process parameters on surface quality.The study compared the chip formation mechanism and surface quality between dry electrical discharge assisted grinding and conventional grinding,revealing relationships between surface roughness,grinding force,grinding temperature,and related parameters.The results indicate that the proposed grinding method leads to smaller chip sizes,lower grinding forces and temperatures,and an average reduction of 19.2%in surface roughness compared to conventional grinding.The axial,tangential,and normal grinding forces were reduced by roughly 10.5%,37.8%,and 23.0%,respectively.The optimized process parameters were determined to be N=2500 r/min,vf=30 mm/min,a=10μm,E=15 V,f=5000 Hz,dc=80%,resulting in a surface roughness of 0.161μm.
基金financially supported by the National Natural Science Foundation of China(Nos.92160301,92060203,52175415 and 52205475)the Science Center for Gas Turbine Project(Nos.P2022-AB-Ⅳ-002-001 and P2023-B-Ⅳ-003-001)+4 种基金the Natural Science Foundation of Jiangsu Province(No.BK20210295)the Superior Postdoctoral Project of Jiangsu Province(No.2022ZB215)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_0355)the Interdisciplinary Innovation Fund for Doctoral Students of Nanjing University of Aeronautics and Astronautics(KXKCXJJ202305)the Fundamental Research Funds for the Central Universities(Nos.NS2023028 and NG2024015)。
文摘Gamma titanium-aluminum intermetallic compounds(γ-TiAl)have gained considerable attentions in the aerospace industry due to their exceptional thermal resilience and comprehensive attributes,making them a prime example of lightweight and advanced materials.To address the frequent occurrence of burns and severe tool deterioration during the process of high-efficiency deep grinding(HEDG)onγ-TiAl alloys,ultrasonic vibration-assisted high-efficiency deep grinding(UVHEDG)has been emerged.Results indicate that in UVHEDG,the grinding temperature is on average 15.4%lower than HEDG due to the employment of ultrasonic vibrations,enhancing coolant penetration into the grinding area and thus reducing heat generation.Besides,UVHEDG possesses superior performance in terms of grinding forces compared to HEDG.As the material removal volume(MRV)increases,the tangential grinding force(F_(t))and normal grinding force(F_(n))of UVHEDG increase but to a lesser extent than in HEDG,with an average reduction of16.25%and 14.7%,respectively.UVHEDG primarily experiences microfracture of grains,whereas HEDG undergoes large-scale wear later in the process due to increased grinding forces.The surface roughness(R_(a))characteristics of UVHEDG are superior,with the average value of R_(a)decreasing by 46.5%compared to HEDG as MRV increases.The surface morphology in UVHEDG exhibits enhanced smoothness and a shallower layer of plastic deformation.Grinding chips generated by UVHEDG show a more shear-like shape,with the applied influence of ultrasonic vibration on chip morphology,thereby impacting material removal behaviors.These aforementioned findings contribute to enhanced machining efficiency and product quality ofγ-TiAl alloys after employing ultrasonic vibrations into HEDG.
基金Supported by National Science and Technology Major Project of China(Grant No.20133ZX04002-031)Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.551121063)State Key Laboratory of Mechanical System and Vibration of China(Grant No.MSV2D2014112)
文摘Recent research on the grinding force involved in cylindrical plunge grinding has focused mainly on steady-state conditions.Unlike in conventional external cylindrical plunge grinding,the conditions between the grinding wheel and the crankpin change periodically in path controlled grinding because of the eccentricity of the crankpin and the constant rotational speed of the crankshaft.The objective of this study is to investigate the effects of various grinding conditions on the characteristics of the grinding force during continuous path controlled grinding.Path controlled plunge grinding is conducted at a constant rotational speed using a cubic boron nitride（CBN）wheel.The grinding force is determined by measuring the torque.The experimental results show that the force and torque vary sinusoidally during dry grinding and load grinding.The variations in the results reveal that the resultant grinding force and torque decrease with higher grinding speeds and increase with higher peripheral speeds of the pin and higher grinding depths.In path controlled grinding,unlike in conventional external cylindrical plunge grinding,the axial grinding force cannot be disregarded.The speeds and speed ratios of the workpiece and wheel are also analyzed,and the analysis results show that up-grinding and down-grinding occur during the grinding process.This paper proposes a method for describing the force behavior under varied process conditions during continuous path controlled grinding,which provides a beneficial reference for describing the material removal mechanism and for optimizing continuous controlled crankpin grinding.
基金co-supported by the National Natural Science Foundation of China (Nos. 51175276 and 51575290)the Qingdao Science and Technology Program of Basic Research Projects (No. 14-2-4-18-jch) of Chinathe Huangdao District Application Science and Technology Project (No. 2014-1-55) of China
文摘Vegetable oil can be used as a base oil in minimal quantity of lubrication (MQL). This study compared the performances of MQL grinding by using castor oil, soybean oil, rapeseed oil, corn oil, sunflower oil, peanut oil, and palm oil as base oils. A K-P36 numerical-control precision surface grinder was used to perform plain grinding on a workpiece material with a high-temperature nickel base alloy. A YDM-III 99 three-dimensional dynamometer was used to measure grinding force, and a clip-type thermocouple was used to determine grinding temperature. The grinding force, grinding temperature, and energy ratio coefficient of MQL grinding were compared among the seven vegetable oil types. Results revealed that (1) castor oil-based MQL grinding yields the lowest grinding force but exhibits the highest grinding temperature and energy ratio coefficient; (2) palm oil-based MQL grinding generates the second lowest grinding force but shows the lowest grinding temperature and energy ratio coefficient; (3) MQL grinding based on the five other vegetable oils produces similar grinding forces, grinding temperatures, and energy ratio coefficients, with values ranging between those of castor oil and palm oil; (4) viscosity significantly influences grinding force and grinding temperature to a greater extent than fatty acid varieties and contents in vegetable oils; (5) although more viscous vegetable oil exhibits greater lubrication and significantly lower grinding force than less viscous vegetable oil, high viscosity reduces the heat exchange capability of vegetable oil and thus yields a high grinding temperature; (6) saturated fatty acid is a more efficient lubricant than unsaturated fatty acid; and (7) a short carbon chain transfers heat more effectively than a long carbon chain. Palm oil is the optimum base oil of MQL grinding, and this base oil yields 26.98 N tangential grinding force, 87.10 N normal grinding force, 119.6 degrees C grinding temperature, and 42.7% energy ratio coefficient. (C) 2015 The Authors. Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.
基金Projects(U1537202,51575305)supported by the National Natural Science Foundation of ChinaProject(61328302)supported by National Security Major Basic Research Program of China
文摘Single grit grinding is the simplified model to abstract the macro scale grinding.Finite element analysis is a strong tool to study the physical fields during a single grit grinding process,compared to experimental research.Based on the dynamic mechanical behavior of 2Cr12Ni4Mo3VNbN steel and the mathematical statistics of abrasive grit,modeling of the single grit grinding process was conducted by using commercial software AdvantEdge.The validation experiment was designed to validate the correctness of the FEA model by contrast with grinding force.The validation result shows that the FEA model can well describe the single grit grinding process.Then the grinding force and multi-physics fields were studied by experimental and simulation results.It was found that both the normal and tangential grinding forces were linearly related to the cutting speed and cutting depth.The maximum temperature is located in the subsurface of the workpiece in front of the grit,while the maximum stress and strain are located under the grit tip.The strain rate can reach as high as about 106 s–1 during the single grit grinding,which is larger than other traditional machining operations.
基金Supported by the State Major Science and Technology Special Projects(2010ZX04003081-03)
文摘The purpose of this study is to investigate the effect of graphite lubricant on the dry grinding performance of Ti-6Al-4Valloy,using graphite-coated,brazed monolayer,cubic boron nitride(cBN)wheels.Brazed monolayer cBN wheels both with and without a coating of polymer-based graphite lubricant are fabricated and subsequently compared for grinding performance based on measurements of grinding temperature,surface microstructure and grinding.In terms of grinding temperature,considerable improvement in dry grinding performance of titanium alloy is achieved using coated brazed monolayer cBN wheels,with 42%—47%reduction in grinding temperature as opposed to uncoated wheels.The grinding force ratio with the coated wheels is observed to remain between 1.45to1.85despite material removal rates reaching up to 1 950mm3/mm.No tangible change in ground titanium surface microstructure is noted as a result of grinding with the graphite coated wheels as opposed to the uncoated ones.
基金financially supported by the National Natural Science Foundation of China (Nos. 51921003, 92160301, 52175415 and 52205475)the Science Center for Gas Turbine Project (No. P2022-A-IV-002-001)+3 种基金the Natural Science Foundation of Jiangsu Province (No. BK20210295)the Superior Postdoctoral Project of Jiangsu Province (No. 2022ZB215)the Open Foundation State Key Laboratory of Mechanical Transmissions (No. SKLMT-MSKFKT-202101)the Special Projects for the Reengineering of Industrial Foundation and the High-quality Development of Manufacturing Industry (No. TC210H02X)
文摘Particle-reinforcing titanium matrix composites(PTMCs)exhibit the sharp raising applications in modern industries owing to its extraordinary physical and mechanical properties.However,the poor grindability and unstable grinding processes due to the existence of TiC particles and TiB short fibres inside PTMCs,leading to the sudden grinding burn and low material removal rate.In this work,a novel radial ultrasonic vibration-assisted grinding(RUVAG)device with a special cross structure was developed to improve machining efficiency and avoid grinding burns.Meanwhile,the resonant modal and transient dynamic characteristics of radial ultrasonic vibration system were discussed.Comparative grinding performance experiments were then conducted under the conventional grinding(CG)and RUVAG using mono-layer cubic boron nitride abrasive wheels,in views of the grinding forces and force ratio,grinding temperature,and ground surface morphology.Results show that the ultrasonic vibration direction can be transformed effectively using the special cross structure of vibration converter,and better vibration homogeneity can be obtained.RUVAG has a smaller tangential grinding force by 5.0%–17.2%than that of CG,but a higher normal grinding force of 6.5%–14.9%,owing to the periodic impact of grinding wheels.In addition,RUVAG possesses a remarkable lower grinding temperature in range of 24.2%–51.8%and a higher material removal rate by 2.8 times compared with CG,resulting from the intermittent cutting behavior between the grinding wheel and workpiece.In this case,the sudden burn can be avoided during high-speed grinding processes.Moreover,the proportion of micro-fracture defects on machined surface is slightly increased once the ultrasonic vibration mode is employed because of the periodic impact on reinforced particles,whereas the pull-out defects of reinforced particles are reduced significantly.
基金co-supported by the National Natural Science Foundation of China (Nos. 51235004, 51375235)the Fundamental Research Funds for the Central Universities (No. NE2014103) of ChinaPriority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) of China
文摘（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were discussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally beneficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.
基金Work supported by the Second Stage of Brain Korea 21 Project
文摘The purpose of this study is to develop a twin wheel creep-feed grinding machine using continuous dressing to machine precise axisymmetric turbine blades that have been difficult to machine using a conventional creep-feed machine.In order to develop such a machine,3D-modeling and machine simulations were performed and a twin wheel creep-feed grinding machine was manufactured.Furthermore,the axisymmetric precision of the machined workpieces through practical machining was evaluated and the quality of the continuous dressing effect of the developed machine was established.In addition,experimental considerations for a proper dresser-to-wheel speed ratio and proper feed rate of the dresser were carried out.As a result,a twin wheel creep-feed grinding machine with continuous dressing is developed through machine simulation,manufacturing and performance evaluation.Optimum condition for the dresser feed rate is 0.3μm/rev.In cases of large dressor-to-wheel speed ratio,grinding efficiency can be enhanced,but the surface roughness shows a conflicting trend.Developed twin wheel creep-feed grinding machine has satisfactory appraisal with regard to surface roughness,flatness,and parallelism.Satisfactory surface roughness below 0.1μm can be obtained for the blade of aircraft.However,in order to perform precise machining,it is necessary to improve the structure of the twin wheel creep-feed grinding machine.
