As a subversive manufacturing technology, additive manufacturing technology has many technical advantages such as high freedom of design and not limited by complex structure of parts. The application of additive manuf...As a subversive manufacturing technology, additive manufacturing technology has many technical advantages such as high freedom of design and not limited by complex structure of parts. The application of additive manufacturing technology to the charge molding of energetic materials will subvert the traditional manufacturing concept of energetic materials, realize the advanced charge design concept, shorten the research and development time of weapons and equipment, and improve the comprehensive performance of weapons and equipment, which is of great significance for the rapid development of high-tech weapons and equipment. This paper analyzes the research progress of additive manufacturing technology in the field of energetic materials at home and abroad and puts forward some suggestions for future research of this technology. .展开更多
By vermicularizing agent containing RE (REFeSi), austempered vermicular graphite cast iron (AVGCI) with RE can be produced with austempered treatment. The process of austenitization of vermicular graphite cast iron (V...By vermicularizing agent containing RE (REFeSi), austempered vermicular graphite cast iron (AVGCI) with RE can be produced with austempered treatment. The process of austenitization of vermicular graphite cast iron (VGCI) with RE and the transformation of AVGCI with RE with temperature increasing were studied by SEM with heating device. Properties of AVGCI with RE, such as tensile strength, elongation, impact toughness, hardness, thermal fatigue resistance, thermal expansive coefficient and weight increasing by oxidation were measured by electron universal testing machine with heating device. Experimental results indicate that AVGCI with RE possesses good comprehensive properties at room and elevated temperatures.展开更多
In order to realize the optimal design of the industrial robot arm structure,an optimization method of the industrial robot arm structure based on green manufacturing technology is proposed.The stability of arm struct...In order to realize the optimal design of the industrial robot arm structure,an optimization method of the industrial robot arm structure based on green manufacturing technology is proposed.The stability of arm structure parameter acquisition can be controlled.The quantitative adjustment model of structural optimization parameters is constructed.The differential fusion control of the arm structure is realized.This paper analyzes the structure parameter law of the robot arm.We use dynamic parameter prediction and output torque parameter compensation method to control the arm structure.According to the adaptive iterative processing results,the arm structure parameter identification is realized.According to the identification results,the cutting parameter optimization method is adopted for the analytical control of the arm structure,and finally the optimized design of the industrial robot arm structure is realized through the green manufacturing technology.The simulation test results show that for the accuracy of the industrial robot arm structure design,this method is better,the output stability is higher,and the arm motion trajectory has a low deviation from the actual motion trajectory,which improves the optimization control and design capabilities of the industrial robot arm structure.展开更多
This paper reviews the development of manufacturing technology and the progress that has so far been made in this field.It points out that manufacturing technology is not only the pillar of material civilization and t...This paper reviews the development of manufacturing technology and the progress that has so far been made in this field.It points out that manufacturing technology is not only the pillar of material civilization and the base of spiritual civilization of man,but also the foundation of a country's competitivendess.The paper also attempts to review the future of manufacturing technology through the description of the new pattern of manufacturing market,new features of manufactured products,new characteristics of technologies as well as the emerging trends of manufacturing enterprises and man-agement in the 21 st cetury.展开更多
Some of the major manufacturing processes and corresponding mechanical properties of titanium clad steel plates were analyzed, and the consequences of research, manufacturing, and application of titanium clad steel pl...Some of the major manufacturing processes and corresponding mechanical properties of titanium clad steel plates were analyzed, and the consequences of research, manufacturing, and application of titanium clad steel plates in both markets of China and overseas were also summarized. As an economical and environmentally friendly technology, the roll bonding process is expected to become the next-generation mainstream process for the manufacturing of titanium clad steel plate. Some of the crucial and most important technical problems of this particular process, including vacuum sealing technology, surface treatment process technology, application of a transition layer, and rolling process, were discussed along with the advantageous mechanical properties and life-cycle economy of these plates processed by this technology. Finally, the market needs, application trends, and requirements of titanium clad steel plate were also considered from industries of petrochemical, shipbuilding, marine, and electric power.展开更多
The advanced manufacturing technology of mechanical products features interaction, and high simulation, etc. In this paper, a digital geometry model for the processing is established with the aid of computer technolog...The advanced manufacturing technology of mechanical products features interaction, and high simulation, etc. In this paper, a digital geometry model for the processing is established with the aid of computer technology, so that the needs of machinery manufacturing production and precision machining can be fulfilled, and also the simulation, validation, comparison, and optimization of many plans can be implemented for ultimately finding out an optimal processing method and realizing the benefit of low cost and high quality. From two different levels of activity and parts, the configuration principle of mechanical products＇ advanced manufacturing technology is defined. Therefore, the advanced manufacturing technology for customizing different products can be derived, and also the reuse of different types of parts is realized. Finally, this is verified with an example.展开更多
Manufacturing of a product is constituted of the va ri ous attributes such as quality, cost, performance, and time to market. Manufactu ring can also be understood as the entire product realization process, from spec ...Manufacturing of a product is constituted of the va ri ous attributes such as quality, cost, performance, and time to market. Manufactu ring can also be understood as the entire product realization process, from spec ification through design and production to marketing and distribution. The induc tion of Information Technology (IT) in manufacturing includes the hardware that computes and communicates, the software that provides data, knowledge, and infor mation while at the same time controlling the hardware, and the interfaces betwe en computers and the tools and machines on the shop floor. The manufacturing pro cess utilizes IT in the design of products and processes, production, and manufa cturing-related business practices. IT applications applied to manufacturing helps in rapid shifts in production fro m one product to another, faster implementation of new concepts in products, fas ter delivery of products to customers, full utilization of capital and human res ources, streamlining of operations to focus on essential business needs, and eli mination of unnecessary or wasteful activities. IT can be used to meet a range of needs of manufacturing decision makers. It can be said that IT is an enabler and facilitator of radical change to culture of manufacturing which is highly co nservative for many good reasons. With increasing global competition, applications of global information technolog y is giving manufacturing unit an opportunity to increase control and enhance co ordination, while opening doors to new global markets and businesses. In some st udies conducted it ahs been shown that how information technology can produce pr oductivity gains and job losses in specific areas, whereas dynamic stability was also achieved through IT in some cases. In a study of an industry the IT has cu t manufacturers cost from eProcurement to web based supply chain management and after sales service. IT has certainly revolutionized the manufacturing and the i ndustries have completely redefined their business by switching over to World Wi de Web. This paper, attempts to review the significant advances and practical applicatio ns of information technology in the field of manufacturing.展开更多
An abstract model and representation method for manufacturing environment is presented based on analysis of process planning tasks and factory configuration capable of handling the process plans. This model has been p...An abstract model and representation method for manufacturing environment is presented based on analysis of process planning tasks and factory configuration capable of handling the process plans. This model has been proved to be applicable to the generative process planning and to shopflow control information integration. A general manufacturing environment modelling tool has been developed under the X-window support to verity the mentioned model and modelling technology.展开更多
Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties,corrosion resistance and good biocompatibility.However,problems such as rejection,shedding and ...Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties,corrosion resistance and good biocompatibility.However,problems such as rejection,shedding and infection will occur after titanium alloy implantation due to the low biological activity of titanium alloy surface.The structures with specific functions,which can enhance osseointegration and antibacterial properties,are fabricated on the surface of titanium implants to improve the biological activity between the titanium implants and human tissues.This paper presents a comprehensive review of recent developments and applications of surface functional structure in titanium and titanium alloy implants.The applications of surface functional structure on different titanium and titanium alloy implants are introduced,and their manufacturing technologies are summarized and compared.Furthermore,the fabrication of various surface functional structures used for titanium and titanium alloy implants is reviewed and analyzed in detail.Finally,the challenges affecting the development of surface functional structures applied in titanium and titanium alloy implants are outlined,and recommendations for future research are presented.展开更多
With unique manufacturing technology,the additive manufacturing technology divides the three-dimensional object into countless two-dimensional laminates.Compared with the traditional material reduction manufacturing m...With unique manufacturing technology,the additive manufacturing technology divides the three-dimensional object into countless two-dimensional laminates.Compared with the traditional material reduction manufacturing method,it has the characteristics of saving materials,being fast,and especially suitable for single and small batch parts and the rapid manufacturing of parts with complex shapes and internal structures.In this paper,various methods of additive manufacturing technology are reviewed.This paper introduces the characteristics of selective laser melting technology and its forming equipment system.On this basis,the technical defects of selective laser melting technology are analyzed,and the status of controlling defects in SLM technology is explained.In the end,the prospects of additive manufacturing technology are described.展开更多
Synchronous rolling-casting freeform manufacturing for Metal(SRCFMM) means that the refined liquid metal is continuously pressed out from the bottom of crucible. There is a horizontal movable plate beneath the outlet....Synchronous rolling-casting freeform manufacturing for Metal(SRCFMM) means that the refined liquid metal is continuously pressed out from the bottom of crucible. There is a horizontal movable plate beneath the outlet. The clearance between the outlet and the plate is about several hundred micrometers. SRCFMM, similar to additive manufacturing, implies layer by layer shaping and consolidation of feedstock to arbitrary configurations, normally using a computer controlled movable plate. The primary dendritic crystal is easily crushed by movement of substrate in the rolling-casting area. ZL104 was used as the test materials, determining the control temperature by differential scanning thermal analysis(DSC), preparing a kind of samples by SR CFMM, then analyzing microstructures and mechanical property of the samples. Characteristics and distribution of the primary particles were assessed by optical microscopy(OM), scanning electron microscopy(SEM), energy dispersive spectrum(EDS) and image analysis software. Mechanical property of the samples was assessed by vickers hardness. The results show that the samples fabricated by SRCFMM have uniform structures and good performances with the velocity of the substrate controlled about 10 cm/s and temperature at about 580 ℃.展开更多
The Chen Zhang Pot, made in the late Warring States period is an openwork bronze pot with gold and silver inlay. It was identified as a first-class historical relic of the nation by the State Administration of Cultura...The Chen Zhang Pot, made in the late Warring States period is an openwork bronze pot with gold and silver inlay. It was identified as a first-class historical relic of the nation by the State Administration of Cultural Heritage in 2001. To explore its manufacturing techniques, XRF, CT and X-Ray photograph microscopic observation were adopted for the non-destructive examination of the Chen Zhang Pot. The analysis data show that many parts of the Chen Zhang Pot were cast separately, and then assembled. It also shows that the composition proportion of each part of the Chen Zhang Pot is different; and the bronze color, hardness and tensile strength are different for each alloy proportion. A variety of decoration techniques were adopted in the manufacturing process, which make the color more diverse and gorgeous. The openwork decoration is the most complex part of the pot, and the gold and silver decoration technique also represents the high level manufacturing technology in the Warring States period. In summary, the Chen Zhang Pot is a unique art treasure, and as a specimen it allows us to study the bronze casting technology in the Warring States period.展开更多
Based on the traditional re-entrant honeycomb,a novel re-entrant octagon honeycomb(ROH)is proposed.The deformation mode of the honeycomb under quasi-static compression is analyzed by numerical simulation,and the resul...Based on the traditional re-entrant honeycomb,a novel re-entrant octagon honeycomb(ROH)is proposed.The deformation mode of the honeycomb under quasi-static compression is analyzed by numerical simulation,and the results are in good agreement with the experimental ones.The deformation modes,mechanical properties,and energy absorption characteristics of ROH along the impact and perpendicular directions gradient design are investigated under different velocities.The results indicated that the deformation mode of ROH is affected by gradient design along the direction of impact and impact speed.In addition,gradient design along the direction of impact can increase the initial peak stress of ROH and accelerate its densification phase.Gradient design perpendicular to the impact direction can enhance the energy absorption performance of ROH,especially for ROH,with wall thickness increasing from the inside outwards.Compared to ROH with uniform wall thickness at the same relative density,ROH with a gradient design can increase the plateau stress by over half.With the elevation of impact velocity,the plateau stress and specific energy absorption exhibit an upward trend,aligning with the dynamic performance pattern observed in conventional honeycombs.The results can be used as a reference for the design and application of honeycomb and provide a new idea for developing more efficient and reliable energy-absorbing materials.展开更多
At present, the most common micro/nano-scale fabri ca tion processes include the plane silicon process based on IC technology, stereo silicon process, LIGA, quasi-LIGA based on near ultra violet deep lithography, MEMS...At present, the most common micro/nano-scale fabri ca tion processes include the plane silicon process based on IC technology, stereo silicon process, LIGA, quasi-LIGA based on near ultra violet deep lithography, MEMS, energy beam etching and micro/nano-machining, etc. A common problem for t hese processes is the difficulty to fabricate arbitrary form for 3-dimensional micro/nano-parts, devices or mechanisms. To develop advanced MEMS manufacturin g technology, and to achieve fabrication of true 3-dimensional parts, devices or mechanisms, this paper proposes a nanofabrication technology for rapid proto typing of 3-dimensional parts, using plasma chemical vapor deposition (PCVD). This process can be describes as follows: A laser beam is produced by a low power, quasi molecule laser. It enters the vac uum chamber through a window, and is focused on with the substrate surface. A ga s in the chamber is ionized by the laser beam to produce PCVD on the substrate s urface, and forms a particle of the size of Ф100 nm (its thickness is about 100 nm). When the laser beam moves along X-axis, many particles form a line. Then the laser beam moves one step in Y-axis to form a new line. A plane is complete d by many lines. Then the substrate moves in Z-axis to form new plane. Eventu ally, many planes form a 3-dimensional component. Using available CAD/CAM softw are with this process, rapid prototyping of complex components can be achieved. A nanometer precision linear motor, such as that described in Chinese national p atent (patent No. ZL 98 2 16753.9), can be used to obtain the nanometer precisio n movements in the process. The process does not require mask, can be used for v arious rapid prototyping materials, to obtain high fabrication precision (its sc ale precision is 15 nm), and larger ratio of height to width of micro/nano-stru cture. It can find widespread applications in the fabrication of micro-mechani sm, trimming IC, and fabricating minilens, etc.展开更多
Surgical meshes have been employed in the management of a variety of pathological conditions including hernia,pelvic floor dysfunctions,periodontal guided bone regeneration,wound healing and more recently for breast p...Surgical meshes have been employed in the management of a variety of pathological conditions including hernia,pelvic floor dysfunctions,periodontal guided bone regeneration,wound healing and more recently for breast plastic surgery after mastectomy.These common pathologies affect a wide portion of the worldwide population;therefore,an effective and enhanced treatment is crucial to ameliorate patients’living conditions both from medical and aesthetic points of view.At present,non-absorbable synthetic polymers are the most widely used class of biomaterials for the manufacturing of mesh implants for hernia,pelvic floor dysfunctions and guided bone regeneration,with polypropylene and poly tetrafluoroethylene being the most common.Biological prostheses,such as surgical grafts,have been employed mainly for breast plastic surgery and wound healing applications.Despite the advantages of mesh implants to the treatment of these conditions,there are still many drawbacks,mainly related to the arising of a huge number of post-operative complications,among which infections are the most common.Developing a mesh that could appropriately integrate with the native tissue,promote its healing and constructive remodelling,is the key aim of ongoing research in the area of surgical mesh implants.To this end,the adoption of new biomaterials including absorbable and natural polymers,the use of drugs and advanced manufacturing technologies,such as 3D printing and electrospinning,are under investigation to address the previously mentioned challenges and improve the outcomes of future clinical practice.The aim of this work is to review the key advantages and disadvantages related to the use of surgical meshes,the main issues characterizing each clinical procedure and the future directions in terms of both novel manufacturing technologies and latest regulatory considerations.展开更多
This paper compares Chinese, Korean, and Japanese shipyard production technology. Development in the world shipbuilding over recent years has influenced focus areas related to shipyard manufacturing technologies and p...This paper compares Chinese, Korean, and Japanese shipyard production technology. Development in the world shipbuilding over recent years has influenced focus areas related to shipyard manufacturing technologies and product performance. Software systems, information technology, production technology, and local challenges of shipyards are compared with shipbuilding outputs among these three countries. Various technologies developments, shipyard production and the problems in Chinese, Japanese, and Korean shipyards are discussed respectively. Finally, future areas of research are pointed out.展开更多
Industry 4.0 as referred to a fourth industrial revolution has endorsed in several national manufacturing development plans such as in Germany, the UK, and China. A set of important pervasive and secondary technologie...Industry 4.0 as referred to a fourth industrial revolution has endorsed in several national manufacturing development plans such as in Germany, the UK, and China. A set of important pervasive and secondary technologies for future manufacturing activities have been identified such as additive manufacturing, sensor technology, big data analytics, Internet of things, robotics, cloud computing, and nanotechnology.展开更多
On January 7, 2015 the project ＂Study on the technology formanufacture of high-spheroidicity FCC catalysts ＂undertakenby the SINOPEC Research Institute of Petroleum Processing（RIPP） has passed the technical apprai...On January 7, 2015 the project ＂Study on the technology formanufacture of high-spheroidicity FCC catalysts ＂undertakenby the SINOPEC Research Institute of Petroleum Processing（RIPP） has passed the technical appraisal organized by theScience and Technology Division of the Sinopec Corp.展开更多
文摘As a subversive manufacturing technology, additive manufacturing technology has many technical advantages such as high freedom of design and not limited by complex structure of parts. The application of additive manufacturing technology to the charge molding of energetic materials will subvert the traditional manufacturing concept of energetic materials, realize the advanced charge design concept, shorten the research and development time of weapons and equipment, and improve the comprehensive performance of weapons and equipment, which is of great significance for the rapid development of high-tech weapons and equipment. This paper analyzes the research progress of additive manufacturing technology in the field of energetic materials at home and abroad and puts forward some suggestions for future research of this technology. .
文摘By vermicularizing agent containing RE (REFeSi), austempered vermicular graphite cast iron (AVGCI) with RE can be produced with austempered treatment. The process of austenitization of vermicular graphite cast iron (VGCI) with RE and the transformation of AVGCI with RE with temperature increasing were studied by SEM with heating device. Properties of AVGCI with RE, such as tensile strength, elongation, impact toughness, hardness, thermal fatigue resistance, thermal expansive coefficient and weight increasing by oxidation were measured by electron universal testing machine with heating device. Experimental results indicate that AVGCI with RE possesses good comprehensive properties at room and elevated temperatures.
基金the Research Fund of Faculty of Engineering,University of Malaya(Grant No.GPF052A-2018)
文摘In order to realize the optimal design of the industrial robot arm structure,an optimization method of the industrial robot arm structure based on green manufacturing technology is proposed.The stability of arm structure parameter acquisition can be controlled.The quantitative adjustment model of structural optimization parameters is constructed.The differential fusion control of the arm structure is realized.This paper analyzes the structure parameter law of the robot arm.We use dynamic parameter prediction and output torque parameter compensation method to control the arm structure.According to the adaptive iterative processing results,the arm structure parameter identification is realized.According to the identification results,the cutting parameter optimization method is adopted for the analytical control of the arm structure,and finally the optimized design of the industrial robot arm structure is realized through the green manufacturing technology.The simulation test results show that for the accuracy of the industrial robot arm structure design,this method is better,the output stability is higher,and the arm motion trajectory has a low deviation from the actual motion trajectory,which improves the optimization control and design capabilities of the industrial robot arm structure.
文摘This paper reviews the development of manufacturing technology and the progress that has so far been made in this field.It points out that manufacturing technology is not only the pillar of material civilization and the base of spiritual civilization of man,but also the foundation of a country's competitivendess.The paper also attempts to review the future of manufacturing technology through the description of the new pattern of manufacturing market,new features of manufactured products,new characteristics of technologies as well as the emerging trends of manufacturing enterprises and man-agement in the 21 st cetury.
文摘Some of the major manufacturing processes and corresponding mechanical properties of titanium clad steel plates were analyzed, and the consequences of research, manufacturing, and application of titanium clad steel plates in both markets of China and overseas were also summarized. As an economical and environmentally friendly technology, the roll bonding process is expected to become the next-generation mainstream process for the manufacturing of titanium clad steel plate. Some of the crucial and most important technical problems of this particular process, including vacuum sealing technology, surface treatment process technology, application of a transition layer, and rolling process, were discussed along with the advantageous mechanical properties and life-cycle economy of these plates processed by this technology. Finally, the market needs, application trends, and requirements of titanium clad steel plate were also considered from industries of petrochemical, shipbuilding, marine, and electric power.
文摘The advanced manufacturing technology of mechanical products features interaction, and high simulation, etc. In this paper, a digital geometry model for the processing is established with the aid of computer technology, so that the needs of machinery manufacturing production and precision machining can be fulfilled, and also the simulation, validation, comparison, and optimization of many plans can be implemented for ultimately finding out an optimal processing method and realizing the benefit of low cost and high quality. From two different levels of activity and parts, the configuration principle of mechanical products＇ advanced manufacturing technology is defined. Therefore, the advanced manufacturing technology for customizing different products can be derived, and also the reuse of different types of parts is realized. Finally, this is verified with an example.
文摘Manufacturing of a product is constituted of the va ri ous attributes such as quality, cost, performance, and time to market. Manufactu ring can also be understood as the entire product realization process, from spec ification through design and production to marketing and distribution. The induc tion of Information Technology (IT) in manufacturing includes the hardware that computes and communicates, the software that provides data, knowledge, and infor mation while at the same time controlling the hardware, and the interfaces betwe en computers and the tools and machines on the shop floor. The manufacturing pro cess utilizes IT in the design of products and processes, production, and manufa cturing-related business practices. IT applications applied to manufacturing helps in rapid shifts in production fro m one product to another, faster implementation of new concepts in products, fas ter delivery of products to customers, full utilization of capital and human res ources, streamlining of operations to focus on essential business needs, and eli mination of unnecessary or wasteful activities. IT can be used to meet a range of needs of manufacturing decision makers. It can be said that IT is an enabler and facilitator of radical change to culture of manufacturing which is highly co nservative for many good reasons. With increasing global competition, applications of global information technolog y is giving manufacturing unit an opportunity to increase control and enhance co ordination, while opening doors to new global markets and businesses. In some st udies conducted it ahs been shown that how information technology can produce pr oductivity gains and job losses in specific areas, whereas dynamic stability was also achieved through IT in some cases. In a study of an industry the IT has cu t manufacturers cost from eProcurement to web based supply chain management and after sales service. IT has certainly revolutionized the manufacturing and the i ndustries have completely redefined their business by switching over to World Wi de Web. This paper, attempts to review the significant advances and practical applicatio ns of information technology in the field of manufacturing.
文摘An abstract model and representation method for manufacturing environment is presented based on analysis of process planning tasks and factory configuration capable of handling the process plans. This model has been proved to be applicable to the generative process planning and to shopflow control information integration. A general manufacturing environment modelling tool has been developed under the X-window support to verity the mentioned model and modelling technology.
基金Supported by National Natural Science Foundation of China (Grant Nos.52235011,51905352)Shenzhen Municipal Excellent Science and Technology Creative Talent Training Program (Grant No.RCBS20210609103819021)+1 种基金Guangdong Provincial Basic and Applied Basic Research Foundation (Grant No.2023B1515120086)Shenzhen Municipal Science and Technology Planning Project (Grant No.CJGJZD20230724093600001)。
文摘Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties,corrosion resistance and good biocompatibility.However,problems such as rejection,shedding and infection will occur after titanium alloy implantation due to the low biological activity of titanium alloy surface.The structures with specific functions,which can enhance osseointegration and antibacterial properties,are fabricated on the surface of titanium implants to improve the biological activity between the titanium implants and human tissues.This paper presents a comprehensive review of recent developments and applications of surface functional structure in titanium and titanium alloy implants.The applications of surface functional structure on different titanium and titanium alloy implants are introduced,and their manufacturing technologies are summarized and compared.Furthermore,the fabrication of various surface functional structures used for titanium and titanium alloy implants is reviewed and analyzed in detail.Finally,the challenges affecting the development of surface functional structures applied in titanium and titanium alloy implants are outlined,and recommendations for future research are presented.
基金Sailing Plan in Guangdong Province(Grant No.2015YT02G090)Development of Additive Manufacturing Powder Materials and Preparation Technology(Grant No.2018002)+1 种基金Yangjiang High Power Laser Application Laboratory Construction(Grant No.2018057)Yangjiang High Power Laser Application Laboratory Co.,Ltd.supports the Construction of New R&D Institutions in the East and Northwest of Guangdong Province(Grant No.20180902).
文摘With unique manufacturing technology,the additive manufacturing technology divides the three-dimensional object into countless two-dimensional laminates.Compared with the traditional material reduction manufacturing method,it has the characteristics of saving materials,being fast,and especially suitable for single and small batch parts and the rapid manufacturing of parts with complex shapes and internal structures.In this paper,various methods of additive manufacturing technology are reviewed.This paper introduces the characteristics of selective laser melting technology and its forming equipment system.On this basis,the technical defects of selective laser melting technology are analyzed,and the status of controlling defects in SLM technology is explained.In the end,the prospects of additive manufacturing technology are described.
基金Funded by the National Natural Science Foundation of China(No.51341009)
文摘Synchronous rolling-casting freeform manufacturing for Metal(SRCFMM) means that the refined liquid metal is continuously pressed out from the bottom of crucible. There is a horizontal movable plate beneath the outlet. The clearance between the outlet and the plate is about several hundred micrometers. SRCFMM, similar to additive manufacturing, implies layer by layer shaping and consolidation of feedstock to arbitrary configurations, normally using a computer controlled movable plate. The primary dendritic crystal is easily crushed by movement of substrate in the rolling-casting area. ZL104 was used as the test materials, determining the control temperature by differential scanning thermal analysis(DSC), preparing a kind of samples by SR CFMM, then analyzing microstructures and mechanical property of the samples. Characteristics and distribution of the primary particles were assessed by optical microscopy(OM), scanning electron microscopy(SEM), energy dispersive spectrum(EDS) and image analysis software. Mechanical property of the samples was assessed by vickers hardness. The results show that the samples fabricated by SRCFMM have uniform structures and good performances with the velocity of the substrate controlled about 10 cm/s and temperature at about 580 ℃.
文摘The Chen Zhang Pot, made in the late Warring States period is an openwork bronze pot with gold and silver inlay. It was identified as a first-class historical relic of the nation by the State Administration of Cultural Heritage in 2001. To explore its manufacturing techniques, XRF, CT and X-Ray photograph microscopic observation were adopted for the non-destructive examination of the Chen Zhang Pot. The analysis data show that many parts of the Chen Zhang Pot were cast separately, and then assembled. It also shows that the composition proportion of each part of the Chen Zhang Pot is different; and the bronze color, hardness and tensile strength are different for each alloy proportion. A variety of decoration techniques were adopted in the manufacturing process, which make the color more diverse and gorgeous. The openwork decoration is the most complex part of the pot, and the gold and silver decoration technique also represents the high level manufacturing technology in the Warring States period. In summary, the Chen Zhang Pot is a unique art treasure, and as a specimen it allows us to study the bronze casting technology in the Warring States period.
基金This work is supported by the National Natural Science Foundation of China(No.11902232).
文摘Based on the traditional re-entrant honeycomb,a novel re-entrant octagon honeycomb(ROH)is proposed.The deformation mode of the honeycomb under quasi-static compression is analyzed by numerical simulation,and the results are in good agreement with the experimental ones.The deformation modes,mechanical properties,and energy absorption characteristics of ROH along the impact and perpendicular directions gradient design are investigated under different velocities.The results indicated that the deformation mode of ROH is affected by gradient design along the direction of impact and impact speed.In addition,gradient design along the direction of impact can increase the initial peak stress of ROH and accelerate its densification phase.Gradient design perpendicular to the impact direction can enhance the energy absorption performance of ROH,especially for ROH,with wall thickness increasing from the inside outwards.Compared to ROH with uniform wall thickness at the same relative density,ROH with a gradient design can increase the plateau stress by over half.With the elevation of impact velocity,the plateau stress and specific energy absorption exhibit an upward trend,aligning with the dynamic performance pattern observed in conventional honeycombs.The results can be used as a reference for the design and application of honeycomb and provide a new idea for developing more efficient and reliable energy-absorbing materials.
文摘At present, the most common micro/nano-scale fabri ca tion processes include the plane silicon process based on IC technology, stereo silicon process, LIGA, quasi-LIGA based on near ultra violet deep lithography, MEMS, energy beam etching and micro/nano-machining, etc. A common problem for t hese processes is the difficulty to fabricate arbitrary form for 3-dimensional micro/nano-parts, devices or mechanisms. To develop advanced MEMS manufacturin g technology, and to achieve fabrication of true 3-dimensional parts, devices or mechanisms, this paper proposes a nanofabrication technology for rapid proto typing of 3-dimensional parts, using plasma chemical vapor deposition (PCVD). This process can be describes as follows: A laser beam is produced by a low power, quasi molecule laser. It enters the vac uum chamber through a window, and is focused on with the substrate surface. A ga s in the chamber is ionized by the laser beam to produce PCVD on the substrate s urface, and forms a particle of the size of Ф100 nm (its thickness is about 100 nm). When the laser beam moves along X-axis, many particles form a line. Then the laser beam moves one step in Y-axis to form a new line. A plane is complete d by many lines. Then the substrate moves in Z-axis to form new plane. Eventu ally, many planes form a 3-dimensional component. Using available CAD/CAM softw are with this process, rapid prototyping of complex components can be achieved. A nanometer precision linear motor, such as that described in Chinese national p atent (patent No. ZL 98 2 16753.9), can be used to obtain the nanometer precisio n movements in the process. The process does not require mask, can be used for v arious rapid prototyping materials, to obtain high fabrication precision (its sc ale precision is 15 nm), and larger ratio of height to width of micro/nano-stru cture. It can find widespread applications in the fabrication of micro-mechani sm, trimming IC, and fabricating minilens, etc.
文摘Surgical meshes have been employed in the management of a variety of pathological conditions including hernia,pelvic floor dysfunctions,periodontal guided bone regeneration,wound healing and more recently for breast plastic surgery after mastectomy.These common pathologies affect a wide portion of the worldwide population;therefore,an effective and enhanced treatment is crucial to ameliorate patients’living conditions both from medical and aesthetic points of view.At present,non-absorbable synthetic polymers are the most widely used class of biomaterials for the manufacturing of mesh implants for hernia,pelvic floor dysfunctions and guided bone regeneration,with polypropylene and poly tetrafluoroethylene being the most common.Biological prostheses,such as surgical grafts,have been employed mainly for breast plastic surgery and wound healing applications.Despite the advantages of mesh implants to the treatment of these conditions,there are still many drawbacks,mainly related to the arising of a huge number of post-operative complications,among which infections are the most common.Developing a mesh that could appropriately integrate with the native tissue,promote its healing and constructive remodelling,is the key aim of ongoing research in the area of surgical mesh implants.To this end,the adoption of new biomaterials including absorbable and natural polymers,the use of drugs and advanced manufacturing technologies,such as 3D printing and electrospinning,are under investigation to address the previously mentioned challenges and improve the outcomes of future clinical practice.The aim of this work is to review the key advantages and disadvantages related to the use of surgical meshes,the main issues characterizing each clinical procedure and the future directions in terms of both novel manufacturing technologies and latest regulatory considerations.
文摘This paper compares Chinese, Korean, and Japanese shipyard production technology. Development in the world shipbuilding over recent years has influenced focus areas related to shipyard manufacturing technologies and product performance. Software systems, information technology, production technology, and local challenges of shipyards are compared with shipbuilding outputs among these three countries. Various technologies developments, shipyard production and the problems in Chinese, Japanese, and Korean shipyards are discussed respectively. Finally, future areas of research are pointed out.
文摘Industry 4.0 as referred to a fourth industrial revolution has endorsed in several national manufacturing development plans such as in Germany, the UK, and China. A set of important pervasive and secondary technologies for future manufacturing activities have been identified such as additive manufacturing, sensor technology, big data analytics, Internet of things, robotics, cloud computing, and nanotechnology.
文摘On January 7, 2015 the project ＂Study on the technology formanufacture of high-spheroidicity FCC catalysts ＂undertakenby the SINOPEC Research Institute of Petroleum Processing（RIPP） has passed the technical appraisal organized by theScience and Technology Division of the Sinopec Corp.
