The gears of new energy vehicles are required to withstand higher rotational speeds and greater loads,which puts forward higher precision essentials for gear manufacturing.However,machining process parameters can caus...The gears of new energy vehicles are required to withstand higher rotational speeds and greater loads,which puts forward higher precision essentials for gear manufacturing.However,machining process parameters can cause changes in cutting force/heat,resulting in affecting gear machining precision.Therefore,this paper studies the effect of different process parameters on gear machining precision.A multi-objective optimization model is established for the relationship between process parameters and tooth surface deviations,tooth profile deviations,and tooth lead deviations through the cutting speed,feed rate,and cutting depth of the worm wheel gear grinding machine.The response surface method(RSM)is used for experimental design,and the corresponding experimental results and optimal process parameters are obtained.Subsequently,gray relational analysis-principal component analysis(GRA-PCA),particle swarm optimization(PSO),and genetic algorithm-particle swarm optimization(GA-PSO)methods are used to analyze the experimental results and obtain different optimal process parameters.The results show that optimal process parameters obtained by the GRA-PCA,PSO,and GA-PSO methods improve the gear machining precision.Moreover,the gear machining precision obtained by GA-PSO is superior to other methods.展开更多
Preparation method of magnetic nanoparticles with core-shell structure was introduced,especially focusing on the preparation principle of sol-gel method,microemulsion method,and self-assembly technique.The application...Preparation method of magnetic nanoparticles with core-shell structure was introduced,especially focusing on the preparation principle of sol-gel method,microemulsion method,and self-assembly technique.The application of core-shell nanoparticles in precision machining was discussed.The Fe_(3)O_(4)@SiO_(2)composite particles were prepared by sol-gel method and were applied to the magnetorheological polishing of titanium alloy plates.Results show that core-shell nanoparticles with higher surface quality can be obtained after processing,compared with those after conventional abrasives.After polishing for 20 min,the surface roughness of the workpiece reaches 23 nm and the scratches are effectively reduced.Finally,the preparation and application of coreshell nanoparticles are summarized and prospected to provide a reference for further research on core-shell nanoparticles.展开更多
The investigation was carried out on the technical problems of finishing the inner surface of elbow parts and the action mechanism of particles in elbow precision machining by abrasive flow.This work was analyzed and ...The investigation was carried out on the technical problems of finishing the inner surface of elbow parts and the action mechanism of particles in elbow precision machining by abrasive flow.This work was analyzed and researched by combining theory,numerical and experimental methods.The direct simulation Monte Carlo(DSMC)method and the finite element analysis method were combined to reveal the random collision of particles during the precision machining of abrasive flow.Under different inlet velocity,volume fraction and abrasive particle size,the dynamic pressure and turbulence flow energy of abrasive flow in elbow were analyzed,and the machining mechanism of particles on the wall and the influence of different machining parameters on the precision machining quality of abrasive flow were obtained.The test results show the order of the influence of different parameters on the quality of abrasive flow precision machining and establish the optimal process parameters.The results of the surface morphology before and after the precision machining of the inner surface of the elbow are discussed,and the surface roughness Ra value is reduced from 1.125μm to 0.295μm after the precision machining of the abrasive flow.The application of DSMC method provides special insights for the development of abrasive flow technology.展开更多
To meet the demands for highly advanced components with ultra precise contour accuracy and optical surface quality arising in the fields of photonics and optics, automotive, medical applications and biotechnology, con...To meet the demands for highly advanced components with ultra precise contour accuracy and optical surface quality arising in the fields of photonics and optics, automotive, medical applications and biotechnology, consumer electronics and renewable energy, more advanced production machines and processes have to be developed. As the complexity of machine tools rises steadily, the automation of manufacture increases rapidly, processes become more integrated and cycle times have to be reduced significantly, challenges of engineering efficient machine tools with respect to these demands expand every day. Especially the manufacture of freeform geometries with non-continuous and asymmetric surfaces requires advanced diamond machining strategies involving highly dynamic axes movements with a high bandwidth and position accuracy. Ultra precision lathes additionally equipped with Slow Tool and Fast Tool systems can be regarded as state-of-the-art machines achieving the objectives of high quality optical components. The mechanical design of such ultra precision machine tools as well as the mechanical integration of additional highly dynamic axes are very well understood today. In contrast to that, neither advanced control strategies for ultra precision machining nor the control integration of additional Fast Tool systems have been sufficiently developed yet. Considering a complex machine setup as a mechatronic system, it becomes obvious that enhancements to further increase the achievable form accuracy and surface quality and at the same time decrease cycle times and error sensitivity can only be accomplished by innovative, integrated control systems. At the Fraunhofer Institute for Production Technology IPT a novel, fully integrated control approach has been developed to overcome the drawbacks of state-of-the-art machine controls for ultra precision processes. Current control systems are often realized as decentralized solutions consisting of various computational hardware components for setpoint generation, machine control, HMI （human machine interface）, Slow Tool control and Fast Tool control. While implementing such a distributed control strategy, many disadvantages arise in terms of complex communication interfaces, discontinuous safety structures, synchronization of cycle times and the machining accuracy as a whole. The novel control approach has been developed as a fully integrated machine control including standard CNC （computer numerical control） and PLC （programmable logic controller） functionality, advanced setpoint generation methods, an extended HMI as well as an FPGA （field programmable gate array）-based controller for a voice coil driven Slow Tool and a piezo driven Fast Tool axis. As the new control system has been implemented as a fully integrated platform using digital communication via EtherCAT, a continuous safety strategy could be realized, the error sensitivity and EMC susceptibility could be significantly decreased and the overall process accuracy from setpoint generation over path interpolation to axes movements could be enhanced. The novel control at the same time offers additional possibilities of automation, process integration, online data acquisition and evaluation as well as error compensation methods.展开更多
With the continuous collaborative innovation and development of Internet technology and mechanical manufacturing technology, the realization of precision machining process has become the leading innovative technology ...With the continuous collaborative innovation and development of Internet technology and mechanical manufacturing technology, the realization of precision machining process has become the leading innovative technology in the manufacturing industry. China is a big industrial country, and industry is one of the important industrial forms to promote economic development. The machinery manufacturing industry accounts for half of the construction work of industrial engineering projects. However, in order to transform China from an industrial power to an industrial power, the mechanical manufacturing industry needs to be improved from the material, structure, technology and other aspects, combined with advanced information technology means, using scientific and normative principles to complete the mechanical manufacturing content. Next, the article discusses the application of modern mechanical manufacturing technology and precision machining technology.展开更多
As the technical content of promoting industrial development in the industrial field, the in-depth study of modern mechanical manufacturing technology and precision machining technology is not only conducive to improv...As the technical content of promoting industrial development in the industrial field, the in-depth study of modern mechanical manufacturing technology and precision machining technology is not only conducive to improving the development level of China's manufacturing industry, but also of great significance to industrial enterprises. However, due to the late development of advanced technology in China, the development of mechanical manufacturing technology and precision machining technology is not perfect, and there are still some problems, such as insufficient degree of automation, inadequate application of machining technology and so on. Relevant enterprises should carry out analysis and research, understand the characteristics and advantages of modern machinery manufacturing and the application mode of precision machining technology, select the integrated application of technology according to different product characteristics and requirements, improve the quality of machinery manufacturing and service quality, promote the accelerated development of China’s machinery manufacturing industry and contribute to China’s economic construction.展开更多
In the process of machining, it is difficult to eliminate the errors due to various factors, which will affect the final product quality. In order to actively control the errors in mechanical processing, it is necessa...In the process of machining, it is difficult to eliminate the errors due to various factors, which will affect the final product quality. In order to actively control the errors in mechanical processing, it is necessary to effectively apply modern mechanical processing technology and actively adopt precision processing technology to ensure the product quality and meet the increasing demand of users. Precision machining technology and mechanical design and manufacturing technology are complementary relations. They are interrelated and promote each other. This benign relationship greatly promotes the development of China's economy and industry.展开更多
Modern mechanical manufacturing technology and precision machining technology have a positive role in promoting the whole industrial production. However, with the development of modern science and technology, the actu...Modern mechanical manufacturing technology and precision machining technology have a positive role in promoting the whole industrial production. However, with the development of modern science and technology, the actual requirements of modern mechanical manufacturing technology and precision machining technology are gradually improving, forcing the current enterprises to make appropriate adjustments in combination with the actual requirements of modern industrial production. Therefore, under the requirements of current production management, this paper makes a comprehensive analysis and exploration of the relationship between modern mechanical manufacturing technology and precision processing technology, further combs out the practical problems existing in the whole industrial production of modern mechanical manufacturing technology and precision processing technology, and judges the relevant contents involved in the modern mechanical manufacturing and processing technology, in order to promote the transformation of industrial production mode and improve the overall quality of industrial production management in our country.展开更多
In the workshop of Guangshan White Shark Card Clothing Co.,Ltd.,precision machines are meticulously crafting the tips of card clothing with millimeter-level accuracy.These seemingly tiny textile accessories play a cru...In the workshop of Guangshan White Shark Card Clothing Co.,Ltd.,precision machines are meticulously crafting the tips of card clothing with millimeter-level accuracy.These seemingly tiny textile accessories play a crucial role in the global cotton and chemical fiber industry chains.As China's textile industry encounters trade barriers in the process of globalization,this company specializing in card clothing manufacturing is striving to explore a differentiated path in overseas markets.展开更多
Machine tool thermal error is an important reason for poor machining accuracy. Thermal error compensation is a primary technology in accuracy control. To build thermal error model, temperature variables are needed to ...Machine tool thermal error is an important reason for poor machining accuracy. Thermal error compensation is a primary technology in accuracy control. To build thermal error model, temperature variables are needed to be divided into several groups on an appropriate threshold. Currently, group threshold value is mainly determined by researchers experience. Few studies focus on group threshold in temperature variable grouping. Since the threshold is important in error compensation, this paper arms to find out an optimal threshold to realize temperature variable optimization in thermal error modeling. Firstly, correlation coefficient is used to express membership grade of temperature variables, and the theory of fuzzy transitive closure is applied to obtain relational matrix of temperature variables. Concepts as compact degree and separable degree are introduced. Then evaluation model of temperature variable clustering is built. The optimal threshold and the best temperature variable clustering can be obtained by setting the maximum value of evaluation model as the objective. Finally, correlation coefficients between temperature variables and thermal error are calculated in order to find out optimum temperature variables for thermal error modeling. An experiment is conducted on a precise horizontal machining center. In experiment, three displacement sensors are used to measure spindle thermal error and twenty-nine temperature sensors are utilized to detect the machining center temperature. Experimental result shows that the new method of temperature variable optimization on optimal threshold successfully worked out a best threshold value interval and chose seven temperature variables from twenty-nine temperature measuring points. The model residual of z direction is within 3 μm. Obviously, the proposed new variable optimization method has simple computing process and good modeling accuracy, which is quite fit for thermal error compensation.展开更多
Smart machining has tremendous potential and is becoming one of new generation high value precision manufacturing technologies in line with the advance of Industry 4.0 concepts. This paper presents some innovative des...Smart machining has tremendous potential and is becoming one of new generation high value precision manufacturing technologies in line with the advance of Industry 4.0 concepts. This paper presents some innovative design concepts and, in particular, the development of four types of smart cutting tools, including a force-based smart cutting tool, a temperature-based internally-cooled cutting tool, a fast tool servo （FTS） and smart collets for ultra- precision and micro manufacturing purposes. Implemen- tation and application perspectives of these smart cutting tools are explored and discussed particularly for smart machining against a number of industrial application requirements. They are contamination-free machining, machining of tool-wear-prone Si-based infra-red devices and medical applications, high speed micro milling and micro drilling, etc. Furthermore, implementation tech- niques are presented focusing on： （a） plug-and-produce design principle and the associated smart control algo- rithms, （b） piezoelectric film and surface acoustic wave transducers to measure cutting forces in process, （c） critical cutting temperature control in real-time machining, （d） in- process calibration through machining trials, （e） FE-based design and analysis of smart cutting tools, and （f） applica- tion exemplars on adaptive smart machining.展开更多
The cutting burr is one of the common phenomena occurring in metal cutting.In this paper,the forming processes,main effect factors and change law of the cutting direction burr in orthogonal cutting have been studied a...The cutting burr is one of the common phenomena occurring in metal cutting.In this paper,the forming processes,main effect factors and change law of the cutting direction burr in orthogonal cutting have been studied and related theories are analyzed based on the cutting experiments.The result shows that:(1)the forming processes of cutting direction burr consist of normal cutting,flexure deformation of end surface of workpiece,plastic effect,continuous cutting and shear break separating in orthogonal cutting;(2)a new phenomenon is found that cutting direction burr is formed with the shear break separation of the chip and workpiece machined surfaces;(3)the size of cutting direction burr varies with workpiece materials,cutting parameters and geometric parameters of the cutting tool.展开更多
It is concluded from the results of testing the frequency characteristics of the sub micron precision machine tool servo control system, that the existence of several oscillating modalities is the main factor that aff...It is concluded from the results of testing the frequency characteristics of the sub micron precision machine tool servo control system, that the existence of several oscillating modalities is the main factor that affects the performance of the control system. To compensate for this effect,several concave filters are utilized in the system to improve the control accuracy. The feasibility of compensating for several oscillating modalities with a single concave filter is also studied. By applying a modified Butterworth concave filter to the practical system, the maximum stable state output error remains under ±10 nm in the closed loop positioning system.展开更多
Now vibration isolation of ultra precision machine tool is usually achieved through air springs systems. As far as HCM I sub micro turning machine developed by HIT, an active vibration isolation system that consists o...Now vibration isolation of ultra precision machine tool is usually achieved through air springs systems. As far as HCM I sub micro turning machine developed by HIT, an active vibration isolation system that consists of air springs and electro magnetic actuators was presented. The primary function of air springs is to support the turning machine and to isolate the high frequency vibration. The electro magnetic actuators controlled by fuzzy neural networks isolate the low frequency vibration. The experiment indicates that active vibration isolation system isolates base vibration effectively in all the frequency range. So the vibration of the machine bed is controlled under 10 -6 g and the surface roughness is improved.展开更多
Honing is a machining process which can economically produce exact bores regarding form, geometry and surface quality. During the honing process, the tool, equipped with one or several abrasive honing stones, combines...Honing is a machining process which can economically produce exact bores regarding form, geometry and surface quality. During the honing process, the tool, equipped with one or several abrasive honing stones, combines three movement components： rotation, oscillation in axial direction and radial feed movement of the honing stone. The feed movement is a decisive factor for the results of the honing process and can be controlled either by a gradual lining in fixed time intervals or by the regulation of the occurring forces. The presented studies show different approaches for the regulation of force controlled honing and their effects on the measured forces, the torque and the quality parameters of the process.展开更多
Inconel 718(IN718)alloy is widely applied to fabricate high temperature resistant or corrosion resistant parts due to its excellent mechanical performance.However,the machining of IN718 alloy is difficult as it may ca...Inconel 718(IN718)alloy is widely applied to fabricate high temperature resistant or corrosion resistant parts due to its excellent mechanical performance.However,the machining of IN718 alloy is difficult as it may cause serious tool wear and poor surface quality(SQ)of the workpiece.In this work,grinding experiments on IN718 alloy at different speeds were conducted by using a CBN grinding wheel.The relationship between grinding speed,SQ and subsurface damage(SSD)was well studied.With increasing grinding speed,surface roughness decreased,and SQ was greatly improved.Meanwhile,the microhardness of the grinding surface declined as the grinding speed increased.The SSD depth was almost unchanged when the grinding speed was lower than 15 m/s,then it decreased with higher grinding speeds.It was attributed to the mechanical-thermal synergistic effect in the grinding process.The results indicated that increasing grinding speed can effectively improve the SQ and reduce the SSD of IN718 alloy.The conclusion in the work may also provide insight into processing other hard-to-machining materials.展开更多
This paper conducts research on the hydrostatic gas bearings of precision machine tools,deeply analyzes their static characteristics and optimizes the basic parameters.Firstly,through theoretical modeling,the static c...This paper conducts research on the hydrostatic gas bearings of precision machine tools,deeply analyzes their static characteristics and optimizes the basic parameters.Firstly,through theoretical modeling,the static characteristic equation of the hydrostatic gas bearing was derived,covering key indicators such as stiffness and bearing capacity.Subsequently,combined with the numerical simulation method,the static characteristic performance of the bearing under different working conditions was simulated to verify the accuracy of the theoretical model.The research finds that the static characteristics of gas bearings are significantly affected by parameters such as gas supply pressure and bearing clearance.Based on this,the basic parameters of the bearing were optimized and designed by using the optimization algorithm,and the optimal parameter combination was determined,which significantly improved the load-bearing capacity and stiffness of the bearing while reducing power consumption.The experimental results show that the application of the optimized hydrostatic gas bearing in precision machine tools can significantly improve the processing accuracy and stability,providing a theoretical basis and technical support for the design of high-performance bearings in high-end precision machine tools,and has important engineering application value.展开更多
In this paper, a new forming model of the feed direction burr for drilling process is presented. The feed direction burr formation is experimented and studied. The related theories are analyzed, and the influential ...In this paper, a new forming model of the feed direction burr for drilling process is presented. The feed direction burr formation is experimented and studied. The related theories are analyzed, and the influential factors of the feed direction burrs are pointed out. Furthermore, a certain number of new measures to prevent and decrease the burr in drilling process are advanced.展开更多
基金Projects(U22B2084,52275483,52075142)supported by the National Natural Science Foundation of ChinaProject(2023ZY01050)supported by the Ministry of Industry and Information Technology High Quality Development,China。
文摘The gears of new energy vehicles are required to withstand higher rotational speeds and greater loads,which puts forward higher precision essentials for gear manufacturing.However,machining process parameters can cause changes in cutting force/heat,resulting in affecting gear machining precision.Therefore,this paper studies the effect of different process parameters on gear machining precision.A multi-objective optimization model is established for the relationship between process parameters and tooth surface deviations,tooth profile deviations,and tooth lead deviations through the cutting speed,feed rate,and cutting depth of the worm wheel gear grinding machine.The response surface method(RSM)is used for experimental design,and the corresponding experimental results and optimal process parameters are obtained.Subsequently,gray relational analysis-principal component analysis(GRA-PCA),particle swarm optimization(PSO),and genetic algorithm-particle swarm optimization(GA-PSO)methods are used to analyze the experimental results and obtain different optimal process parameters.The results show that optimal process parameters obtained by the GRA-PCA,PSO,and GA-PSO methods improve the gear machining precision.Moreover,the gear machining precision obtained by GA-PSO is superior to other methods.
基金National Natural Science Foundation of China(52265056)Lanzhou Youth Talent Project(2023-QN-38)Hongliu Youth Fund of Lanzhou University of Technology(07/062004)。
文摘Preparation method of magnetic nanoparticles with core-shell structure was introduced,especially focusing on the preparation principle of sol-gel method,microemulsion method,and self-assembly technique.The application of core-shell nanoparticles in precision machining was discussed.The Fe_(3)O_(4)@SiO_(2)composite particles were prepared by sol-gel method and were applied to the magnetorheological polishing of titanium alloy plates.Results show that core-shell nanoparticles with higher surface quality can be obtained after processing,compared with those after conventional abrasives.After polishing for 20 min,the surface roughness of the workpiece reaches 23 nm and the scratches are effectively reduced.Finally,the preparation and application of coreshell nanoparticles are summarized and prospected to provide a reference for further research on core-shell nanoparticles.
基金Projects(51206011,U1937201)supported by the National Natural Science Foundation of ChinaProject(20200301040RQ)supported by the Science and Technology Development Program of Jilin Province,China+1 种基金Project(JJKH20190541KJ)supported by the Education Department of Jilin Province,ChinaProject(18DY017)supported by Changchun Science and Technology Program of Changchun City,China。
文摘The investigation was carried out on the technical problems of finishing the inner surface of elbow parts and the action mechanism of particles in elbow precision machining by abrasive flow.This work was analyzed and researched by combining theory,numerical and experimental methods.The direct simulation Monte Carlo(DSMC)method and the finite element analysis method were combined to reveal the random collision of particles during the precision machining of abrasive flow.Under different inlet velocity,volume fraction and abrasive particle size,the dynamic pressure and turbulence flow energy of abrasive flow in elbow were analyzed,and the machining mechanism of particles on the wall and the influence of different machining parameters on the precision machining quality of abrasive flow were obtained.The test results show the order of the influence of different parameters on the quality of abrasive flow precision machining and establish the optimal process parameters.The results of the surface morphology before and after the precision machining of the inner surface of the elbow are discussed,and the surface roughness Ra value is reduced from 1.125μm to 0.295μm after the precision machining of the abrasive flow.The application of DSMC method provides special insights for the development of abrasive flow technology.
文摘To meet the demands for highly advanced components with ultra precise contour accuracy and optical surface quality arising in the fields of photonics and optics, automotive, medical applications and biotechnology, consumer electronics and renewable energy, more advanced production machines and processes have to be developed. As the complexity of machine tools rises steadily, the automation of manufacture increases rapidly, processes become more integrated and cycle times have to be reduced significantly, challenges of engineering efficient machine tools with respect to these demands expand every day. Especially the manufacture of freeform geometries with non-continuous and asymmetric surfaces requires advanced diamond machining strategies involving highly dynamic axes movements with a high bandwidth and position accuracy. Ultra precision lathes additionally equipped with Slow Tool and Fast Tool systems can be regarded as state-of-the-art machines achieving the objectives of high quality optical components. The mechanical design of such ultra precision machine tools as well as the mechanical integration of additional highly dynamic axes are very well understood today. In contrast to that, neither advanced control strategies for ultra precision machining nor the control integration of additional Fast Tool systems have been sufficiently developed yet. Considering a complex machine setup as a mechatronic system, it becomes obvious that enhancements to further increase the achievable form accuracy and surface quality and at the same time decrease cycle times and error sensitivity can only be accomplished by innovative, integrated control systems. At the Fraunhofer Institute for Production Technology IPT a novel, fully integrated control approach has been developed to overcome the drawbacks of state-of-the-art machine controls for ultra precision processes. Current control systems are often realized as decentralized solutions consisting of various computational hardware components for setpoint generation, machine control, HMI （human machine interface）, Slow Tool control and Fast Tool control. While implementing such a distributed control strategy, many disadvantages arise in terms of complex communication interfaces, discontinuous safety structures, synchronization of cycle times and the machining accuracy as a whole. The novel control approach has been developed as a fully integrated machine control including standard CNC （computer numerical control） and PLC （programmable logic controller） functionality, advanced setpoint generation methods, an extended HMI as well as an FPGA （field programmable gate array）-based controller for a voice coil driven Slow Tool and a piezo driven Fast Tool axis. As the new control system has been implemented as a fully integrated platform using digital communication via EtherCAT, a continuous safety strategy could be realized, the error sensitivity and EMC susceptibility could be significantly decreased and the overall process accuracy from setpoint generation over path interpolation to axes movements could be enhanced. The novel control at the same time offers additional possibilities of automation, process integration, online data acquisition and evaluation as well as error compensation methods.
文摘With the continuous collaborative innovation and development of Internet technology and mechanical manufacturing technology, the realization of precision machining process has become the leading innovative technology in the manufacturing industry. China is a big industrial country, and industry is one of the important industrial forms to promote economic development. The machinery manufacturing industry accounts for half of the construction work of industrial engineering projects. However, in order to transform China from an industrial power to an industrial power, the mechanical manufacturing industry needs to be improved from the material, structure, technology and other aspects, combined with advanced information technology means, using scientific and normative principles to complete the mechanical manufacturing content. Next, the article discusses the application of modern mechanical manufacturing technology and precision machining technology.
文摘As the technical content of promoting industrial development in the industrial field, the in-depth study of modern mechanical manufacturing technology and precision machining technology is not only conducive to improving the development level of China's manufacturing industry, but also of great significance to industrial enterprises. However, due to the late development of advanced technology in China, the development of mechanical manufacturing technology and precision machining technology is not perfect, and there are still some problems, such as insufficient degree of automation, inadequate application of machining technology and so on. Relevant enterprises should carry out analysis and research, understand the characteristics and advantages of modern machinery manufacturing and the application mode of precision machining technology, select the integrated application of technology according to different product characteristics and requirements, improve the quality of machinery manufacturing and service quality, promote the accelerated development of China’s machinery manufacturing industry and contribute to China’s economic construction.
文摘In the process of machining, it is difficult to eliminate the errors due to various factors, which will affect the final product quality. In order to actively control the errors in mechanical processing, it is necessary to effectively apply modern mechanical processing technology and actively adopt precision processing technology to ensure the product quality and meet the increasing demand of users. Precision machining technology and mechanical design and manufacturing technology are complementary relations. They are interrelated and promote each other. This benign relationship greatly promotes the development of China's economy and industry.
文摘Modern mechanical manufacturing technology and precision machining technology have a positive role in promoting the whole industrial production. However, with the development of modern science and technology, the actual requirements of modern mechanical manufacturing technology and precision machining technology are gradually improving, forcing the current enterprises to make appropriate adjustments in combination with the actual requirements of modern industrial production. Therefore, under the requirements of current production management, this paper makes a comprehensive analysis and exploration of the relationship between modern mechanical manufacturing technology and precision processing technology, further combs out the practical problems existing in the whole industrial production of modern mechanical manufacturing technology and precision processing technology, and judges the relevant contents involved in the modern mechanical manufacturing and processing technology, in order to promote the transformation of industrial production mode and improve the overall quality of industrial production management in our country.
文摘In the workshop of Guangshan White Shark Card Clothing Co.,Ltd.,precision machines are meticulously crafting the tips of card clothing with millimeter-level accuracy.These seemingly tiny textile accessories play a crucial role in the global cotton and chemical fiber industry chains.As China's textile industry encounters trade barriers in the process of globalization,this company specializing in card clothing manufacturing is striving to explore a differentiated path in overseas markets.
基金supported by Jiangsu Provincial Prospective Joint Research Foundation for Industry-University-Research of China (Grant No. BY2009102)Henan Provincial Major Scientific and Technological Projects of China (Grant No. 102102210050)
文摘Machine tool thermal error is an important reason for poor machining accuracy. Thermal error compensation is a primary technology in accuracy control. To build thermal error model, temperature variables are needed to be divided into several groups on an appropriate threshold. Currently, group threshold value is mainly determined by researchers experience. Few studies focus on group threshold in temperature variable grouping. Since the threshold is important in error compensation, this paper arms to find out an optimal threshold to realize temperature variable optimization in thermal error modeling. Firstly, correlation coefficient is used to express membership grade of temperature variables, and the theory of fuzzy transitive closure is applied to obtain relational matrix of temperature variables. Concepts as compact degree and separable degree are introduced. Then evaluation model of temperature variable clustering is built. The optimal threshold and the best temperature variable clustering can be obtained by setting the maximum value of evaluation model as the objective. Finally, correlation coefficients between temperature variables and thermal error are calculated in order to find out optimum temperature variables for thermal error modeling. An experiment is conducted on a precise horizontal machining center. In experiment, three displacement sensors are used to measure spindle thermal error and twenty-nine temperature sensors are utilized to detect the machining center temperature. Experimental result shows that the new method of temperature variable optimization on optimal threshold successfully worked out a best threshold value interval and chose seven temperature variables from twenty-nine temperature measuring points. The model residual of z direction is within 3 μm. Obviously, the proposed new variable optimization method has simple computing process and good modeling accuracy, which is quite fit for thermal error compensation.
基金Supported by the UK Technology Strategy Board(TSB)(SEEM Project,Contract No.:BD266E)Innovate UK(KTP Project,Contract No.:9277)
文摘Smart machining has tremendous potential and is becoming one of new generation high value precision manufacturing technologies in line with the advance of Industry 4.0 concepts. This paper presents some innovative design concepts and, in particular, the development of four types of smart cutting tools, including a force-based smart cutting tool, a temperature-based internally-cooled cutting tool, a fast tool servo （FTS） and smart collets for ultra- precision and micro manufacturing purposes. Implemen- tation and application perspectives of these smart cutting tools are explored and discussed particularly for smart machining against a number of industrial application requirements. They are contamination-free machining, machining of tool-wear-prone Si-based infra-red devices and medical applications, high speed micro milling and micro drilling, etc. Furthermore, implementation tech- niques are presented focusing on： （a） plug-and-produce design principle and the associated smart control algo- rithms, （b） piezoelectric film and surface acoustic wave transducers to measure cutting forces in process, （c） critical cutting temperature control in real-time machining, （d） in- process calibration through machining trials, （e） FE-based design and analysis of smart cutting tools, and （f） applica- tion exemplars on adaptive smart machining.
基金Supported by National Natural Science Foundation of China (No.59775071).
文摘The cutting burr is one of the common phenomena occurring in metal cutting.In this paper,the forming processes,main effect factors and change law of the cutting direction burr in orthogonal cutting have been studied and related theories are analyzed based on the cutting experiments.The result shows that:(1)the forming processes of cutting direction burr consist of normal cutting,flexure deformation of end surface of workpiece,plastic effect,continuous cutting and shear break separating in orthogonal cutting;(2)a new phenomenon is found that cutting direction burr is formed with the shear break separation of the chip and workpiece machined surfaces;(3)the size of cutting direction burr varies with workpiece materials,cutting parameters and geometric parameters of the cutting tool.
文摘It is concluded from the results of testing the frequency characteristics of the sub micron precision machine tool servo control system, that the existence of several oscillating modalities is the main factor that affects the performance of the control system. To compensate for this effect,several concave filters are utilized in the system to improve the control accuracy. The feasibility of compensating for several oscillating modalities with a single concave filter is also studied. By applying a modified Butterworth concave filter to the practical system, the maximum stable state output error remains under ±10 nm in the closed loop positioning system.
文摘Now vibration isolation of ultra precision machine tool is usually achieved through air springs systems. As far as HCM I sub micro turning machine developed by HIT, an active vibration isolation system that consists of air springs and electro magnetic actuators was presented. The primary function of air springs is to support the turning machine and to isolate the high frequency vibration. The electro magnetic actuators controlled by fuzzy neural networks isolate the low frequency vibration. The experiment indicates that active vibration isolation system isolates base vibration effectively in all the frequency range. So the vibration of the machine bed is controlled under 10 -6 g and the surface roughness is improved.
文摘Honing is a machining process which can economically produce exact bores regarding form, geometry and surface quality. During the honing process, the tool, equipped with one or several abrasive honing stones, combines three movement components： rotation, oscillation in axial direction and radial feed movement of the honing stone. The feed movement is a decisive factor for the results of the honing process and can be controlled either by a gradual lining in fixed time intervals or by the regulation of the occurring forces. The presented studies show different approaches for the regulation of force controlled honing and their effects on the measured forces, the torque and the quality parameters of the process.
基金Supported by Shenzhen Municipal Science and Technology Innovation Commission of China(Grant Nos.KQTD20190929172505711,JSGG20210420091802007,GJHZ20210705141807023).
文摘Inconel 718(IN718)alloy is widely applied to fabricate high temperature resistant or corrosion resistant parts due to its excellent mechanical performance.However,the machining of IN718 alloy is difficult as it may cause serious tool wear and poor surface quality(SQ)of the workpiece.In this work,grinding experiments on IN718 alloy at different speeds were conducted by using a CBN grinding wheel.The relationship between grinding speed,SQ and subsurface damage(SSD)was well studied.With increasing grinding speed,surface roughness decreased,and SQ was greatly improved.Meanwhile,the microhardness of the grinding surface declined as the grinding speed increased.The SSD depth was almost unchanged when the grinding speed was lower than 15 m/s,then it decreased with higher grinding speeds.It was attributed to the mechanical-thermal synergistic effect in the grinding process.The results indicated that increasing grinding speed can effectively improve the SQ and reduce the SSD of IN718 alloy.The conclusion in the work may also provide insight into processing other hard-to-machining materials.
文摘This paper conducts research on the hydrostatic gas bearings of precision machine tools,deeply analyzes their static characteristics and optimizes the basic parameters.Firstly,through theoretical modeling,the static characteristic equation of the hydrostatic gas bearing was derived,covering key indicators such as stiffness and bearing capacity.Subsequently,combined with the numerical simulation method,the static characteristic performance of the bearing under different working conditions was simulated to verify the accuracy of the theoretical model.The research finds that the static characteristics of gas bearings are significantly affected by parameters such as gas supply pressure and bearing clearance.Based on this,the basic parameters of the bearing were optimized and designed by using the optimization algorithm,and the optimal parameter combination was determined,which significantly improved the load-bearing capacity and stiffness of the bearing while reducing power consumption.The experimental results show that the application of the optimized hydrostatic gas bearing in precision machine tools can significantly improve the processing accuracy and stability,providing a theoretical basis and technical support for the design of high-performance bearings in high-end precision machine tools,and has important engineering application value.
文摘In this paper, a new forming model of the feed direction burr for drilling process is presented. The feed direction burr formation is experimented and studied. The related theories are analyzed, and the influential factors of the feed direction burrs are pointed out. Furthermore, a certain number of new measures to prevent and decrease the burr in drilling process are advanced.
