China-made 5-axis simultaneous contouring CNC machine tool and domestically developed industrial computer-aided manufacture （CAM） technology were used for full crown fabrication and measurement of crown accuracy, wi...China-made 5-axis simultaneous contouring CNC machine tool and domestically developed industrial computer-aided manufacture （CAM） technology were used for full crown fabrication and measurement of crown accuracy, with an attempt to establish an open CAM system for dental processing and to promote the introduction of domestic dental computer-aided design （CAD）/CAM system. Commercially available scanning equipment was used to make a basic digital tooth model after preparation of crown, and CAD software that comes with the scanning device was employed to design the crown by using domestic industrial CAM software to process the crown data in order to generate a solid model for machining purpose, and then China-made 5-axis simultaneous contouring CNC machine tool was used to complete machining of the whole crown and the internal accuracy of the crown internal was measured by using 3D-MicroCT. The results showed that China-made 5-axis simultaneous contouring CNC machine tool in combination with domestic industrial CAM technology can be used for crown making and the crown was well positioned in die. The internal accuracy was successfully measured by using 3D-MicroCT. It is concluded that an open CAM system for den-tistry on the basis of China-made 5-axis simultaneous contouring CNC machine tool and domestic industrial CAM software has been established, and development of the system will promote the introduction of domestically-produced dental CAD/CAM system.展开更多
Cam mechanics is one of the most popular devices for generating irregular motions and is widely used in automatic equipment,such as textile machines,internal combustion engines,and other automatic devices.In order to ...Cam mechanics is one of the most popular devices for generating irregular motions and is widely used in automatic equipment,such as textile machines,internal combustion engines,and other automatic devices.In order to obtain a positive motion from the follower using a rotating cam,its shape should be correctly designed and manufactured.The development of an adequate CAD/CAM system for a cam profile CNC grinding machine is necessary to manufacture high-precision cams.The purpose of this study is the development of a CAD/CAM system and profile measuring device for a CNC grinding machine to obtain an optimal grinding speed with a constant surface roughness.Three types of disk cams were manufactured using the proposed algorithm and procedures to verify effectiveness of the developed CAD/CAM system.展开更多
Automatic straightening process is a nonlinear process, and affected by manyfactors. The straightening technology CAM system has been designed and built up to straightenshafts, which mainly consists of the straighteni...Automatic straightening process is a nonlinear process, and affected by manyfactors. The straightening technology CAM system has been designed and built up to straightenshafts, which mainly consists of the straightening technology's database and the model ofstroke-controlled precise straightening calculation model. The operational test of the CAM systemhas been passed.展开更多
The dynamic responses of roller gear indexing cam mechanism are investigated .With applying Lagarange equation and Gear method,motion equations of this mechanism including clearance,motor characteristic,torsion flexib...The dynamic responses of roller gear indexing cam mechanism are investigated .With applying Lagarange equation and Gear method,motion equations of this mechanism including clearance,motor characteristic,torsion flexibility are developed and solved.The results show that clearance affects primarily the response on turret,and has little effects on the responses on rotary table.At the same time,the velocity fluctuation of motor shaft is not serious for the existence of inertia of reducer,and the high frequency of velocity fluctuation of camshaft is related with the torsion stiffness of shaft and the clearance between pairs.展开更多
An integrated CAD/CAPP/CAM system modeling for Electric Discharge Machining (EDM) is constructed on the basis of an integrated engineering database. EDM feature objects are developed using the object oriented database...An integrated CAD/CAPP/CAM system modeling for Electric Discharge Machining (EDM) is constructed on the basis of an integrated engineering database. EDM feature objects are developed using the object oriented database provided by AutoCAD R14, and EDM feature modeling is realized in AutoCAD environments.展开更多
In order to improve competitive ability of market, mo torcycle enterprises, special the small and middle sized ones must use IT to org anize social resource and adopt effective production mode, namely the dispersed ne...In order to improve competitive ability of market, mo torcycle enterprises, special the small and middle sized ones must use IT to org anize social resource and adopt effective production mode, namely the dispersed networked design and manufacturing (DNDM), which was put forward and proved to b e one of vitality production modes in recent years. In responding to the new pro duction mode of VMCE, a dispersed networked CAD/CAM system (DNCADMS) of motorcyc le products should be developed. The objective of this paper is to investigate a new design and manufacturing mode and technical environment of motorcycle produ ction based on the concept of the DNDM for the small and meddle sized motorcycle enterprises. Because there are various CAx software systems, including differen t kinds of isolated CD, CAD, CAE, CAPP, CAM, PDM, and so on, are used at differe nt stages of the life period of motorcycle products under heterogeneous environm ents, to build a DNCADMS of motorcycle with high performance, some key issues, n amely the architecture of the DNCADMS, the integration of the isolated CAx softw are systems (CAxs), the data communication and exchange between these isolated s ystems and the data share problem under the dispersed heterogeneous database env ironment, should be solved well. For this, the idea we propose is the combinatio n of Web, CORBA, STEP and Java, which provides an effective mechanism to support the integration of isolated CAxs, and support communication and interoperabilit y among CAx systems. Each isolated CAx has been encapsulated respectively by a c ontainer, which is implemented by the ORBs and the IDL of the COBRA technology s tandard, and managed by the application index server. Each container is connecte d with the others by a local network or intranet/Extranet/internet and communica tes through network. For exchanging design and manufacturing information and kno wledge via a local network or the Internet, a commmerical product data translato r has been employed as a product data translating server to complete product dat a communication and exchange between the isolated CAx systems. And for solving t he data share problem under the dispersed networked heterogeneous database envir onment, the idea we propose is to build a meta-database for the native database s, which is a dispersed database, and links various native databases into a whol e logical database. For managing the meta-database, the database index server, a Java-based integrating mechanism, has been also put forward in this paper. Th e application and database index servers have been implemented with Java lan guage. Moreover, the native data base and knowledge base related to each isolate d CAx are be integrated into a dispersed database system by a meta-base.展开更多
In this paper, a 'free surface intersection' algorithm is presented. This algorithm consists of two main stages: caculation of initial intersection points and tracing along an intersection curve. This procedur...In this paper, a 'free surface intersection' algorithm is presented. This algorithm consists of two main stages: caculation of initial intersection points and tracing along an intersection curve. This procedure is valid for any parametric bicubic splint surface patch with a'convex hull', or a patch lies within the conwx hull of the control points.展开更多
The purpose of this study was to evaluate and compare the microleakage and marginal discrepancy of ceramic crown-copings fabricated by three different CAD/CAM systems. Material and methods: Thirty extracted premolars ...The purpose of this study was to evaluate and compare the microleakage and marginal discrepancy of ceramic crown-copings fabricated by three different CAD/CAM systems. Material and methods: Thirty extracted premolars were prepared for complete all-ceramic crowns with: total convergence 10-degree, 2 mm occlusal reduction, 4.5 mm height, 1.3 mm circular reduction and chamfer marginal preparation. They were divided into three groups and each group (n = 10) received a ceramic crown-coping fabricated by one of three CAD/CAM systems: Procera, KaVo Everest and Cerec inLab. The copings were cemented with Panavia F 2.0. After thermal cycling, the teeth were immersed in 2% basic fuchsine dye for 24 hours. Microleakage was scored using a five-point scale and evaluated under a stereomicroscope at ×18. Marginal discrepancies were assessed with scanning electronic microscope at ×150, with measurements at 50 different points. Data were subjected to a chisquare test, Kolmogorov-Smirnov test and using Rho Spearman’s correlation test (P 0.05). No significant differences were found in marginal discrepancies for the Procera (62.58 ± 8.98 μm) and KaVo Everest systems (65.54 ± 18.56 μm), (P = 0.941). Significant differences were found for Cerec inLab (132.18 ± 27.75 μm) compared with Procera and KaVo Everest (P = 0.0001). No correlation between the marginal discrepancies and microleakage for the three CAD/CAM crown-copings systems. Conclusions: Cerec inLab CAD/CAM crown-copings showed significantly higher values for microleakage and marginal discrepancy in comparison with Procera and KaVo Everest CAD/CAM crown-copings.展开更多
How CAD design and simulation tools can assist in developing vacuum circuit breaker （VCB） in general is demonstrated. The electric field calculation has been widely utilized for electrical insulation design of VCB. ...How CAD design and simulation tools can assist in developing vacuum circuit breaker （VCB） in general is demonstrated. The electric field calculation has been widely utilized for electrical insulation design of VCB. ADAMS is applied in dynamic simulation to fulfill the complex calculation of mechanical characteristics. Satisfactory simulation results can be obtained by iteratively refining parameters of the model, and it is shown that this scheme can be used to provide a good basis for optimum design of VCB.展开更多
This paper introduces a domestically developed CAD/CAM system,CAX,which is able to meet the needs of small and medium sized enterprises.Firstly,the motivations and principles for the developing of the system are prese...This paper introduces a domestically developed CAD/CAM system,CAX,which is able to meet the needs of small and medium sized enterprises.Firstly,the motivations and principles for the developing of the system are presented.Then,the functions and features of CAX are described.In the 3rd section,the algorithms for generating blending surfaces with both constant radius and variant radii are detailed.Six color plates showing the applications of CAX are included in section 4.Finally,dis- cussed are some enhancements being added to CAX in th future.展开更多
目的:观察微创超薄与计算机辅助设计与制造(Computer Aided Design/Computer Aided Manufacturing,CAD/CAM)全瓷贴面修复前牙间隙的美学效果及对口腔菌群微环境的影响。方法:选取笔者医院2023年2月-2025年2月收治的94例(共135颗患牙)前...目的:观察微创超薄与计算机辅助设计与制造(Computer Aided Design/Computer Aided Manufacturing,CAD/CAM)全瓷贴面修复前牙间隙的美学效果及对口腔菌群微环境的影响。方法:选取笔者医院2023年2月-2025年2月收治的94例(共135颗患牙)前牙间隙患者为研究对象,采用随机数字表法分为两组。微创组47例(67颗患牙),采用微创超薄贴面修复;研究组47例(68颗患牙),采用CAD/CAM全瓷贴面修复。比较两组患者炎症反应、口腔菌群微环境、牙体美观度、修复效果及并发症发生率。结果:治疗后1个月,研究组肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、白细胞介素-1β(IL-1β)水平低于微创组(P<0.05);研究组牙卟啉单胞菌、具核梭杆菌、伴放线放线杆菌数量均低于微创组(P<0.05)。治疗后6个月,研究组红色美学指数评分(Pink Esthetic Score,PES)、改良版美国公共卫生服务(United States Public Health Service,USPHS)评分均高于微创组(P<0.05)。研究组并发症发生率低于微创组(P<0.05)。结论:CAD/CAM全瓷贴面修复前牙间隙修复效果和安全性良好,不仅对患者口腔菌群微环境影响较小,有利于减轻修复后炎症反应,还能明显提升牙体美观度。展开更多
This study investigated the impacts of key parameters in CAM6's deep convection and cloud physics schemes on the simulation of summer-mean precipitation over East Asia through conducting perturbed parameter ensemb...This study investigated the impacts of key parameters in CAM6's deep convection and cloud physics schemes on the simulation of summer-mean precipitation over East Asia through conducting perturbed parameter ensemble(PPE)experiments.Utilizing the experimental platform of CAM6,a suite of 128 PPE simulations spanning 19792014 were generated through simultaneously perturbing 12 selected parameters.Using EOF analysis,this study firstly extracted the first two leading modes of the precipitation simulation biases.The authors further pinpointed the most critical parameters that have the most influential effects on the precipitation simulation biases,through conducting generalized linear model analysis.The first leading mode of precipitation simulation biases is primarily influenced by parameters from the cloud physics scheme,including the linear effects of dcs and eii,and the nonlinear effect of rhminl*dcs.These parameters influence the simulated total precipitation(PrecT)mainly by altering the large-scale precipitation(PrecL).The second leading mode is predominantly governed by the convection scheme parameter dmpdz,reflecting a competition between the changes in convective precipitation(PrecC)and PrecL in response to variations in dmpdz.An increase in dmpdz induces decreased PrecC and increased PrecL in East Asia,and both of the changes collectively shape the ultimate PrecT response to the adjusted dmpdz.Lastly,it is noteworthy that the nonlinear effect due to the interaction among parameters warrants attention when concurrently adjusting multiple parameters,and the precipitation biases from the PPE simulations resemble those identified through EOF analysis on the AMIP simulations,implying our findings may provide potential reference for other AGCMs.展开更多
基金supported by a grant from the PLA Program for Clinical High-tech Projects for Military Hospitals (No. 2010GXJS053)
文摘China-made 5-axis simultaneous contouring CNC machine tool and domestically developed industrial computer-aided manufacture （CAM） technology were used for full crown fabrication and measurement of crown accuracy, with an attempt to establish an open CAM system for dental processing and to promote the introduction of domestic dental computer-aided design （CAD）/CAM system. Commercially available scanning equipment was used to make a basic digital tooth model after preparation of crown, and CAD software that comes with the scanning device was employed to design the crown by using domestic industrial CAM software to process the crown data in order to generate a solid model for machining purpose, and then China-made 5-axis simultaneous contouring CNC machine tool was used to complete machining of the whole crown and the internal accuracy of the crown internal was measured by using 3D-MicroCT. The results showed that China-made 5-axis simultaneous contouring CNC machine tool in combination with domestic industrial CAM technology can be used for crown making and the crown was well positioned in die. The internal accuracy was successfully measured by using 3D-MicroCT. It is concluded that an open CAM system for den-tistry on the basis of China-made 5-axis simultaneous contouring CNC machine tool and domestic industrial CAM software has been established, and development of the system will promote the introduction of domestically-produced dental CAD/CAM system.
基金Project(RTI04-01-03) supported by the Regional Technology Innovation Program of Ministry of Knowledge Economy (MKE),Korea
文摘Cam mechanics is one of the most popular devices for generating irregular motions and is widely used in automatic equipment,such as textile machines,internal combustion engines,and other automatic devices.In order to obtain a positive motion from the follower using a rotating cam,its shape should be correctly designed and manufactured.The development of an adequate CAD/CAM system for a cam profile CNC grinding machine is necessary to manufacture high-precision cams.The purpose of this study is the development of a CAD/CAM system and profile measuring device for a CNC grinding machine to obtain an optimal grinding speed with a constant surface roughness.Three types of disk cams were manufactured using the proposed algorithm and procedures to verify effectiveness of the developed CAD/CAM system.
文摘Automatic straightening process is a nonlinear process, and affected by manyfactors. The straightening technology CAM system has been designed and built up to straightenshafts, which mainly consists of the straightening technology's database and the model ofstroke-controlled precise straightening calculation model. The operational test of the CAM systemhas been passed.
文摘The dynamic responses of roller gear indexing cam mechanism are investigated .With applying Lagarange equation and Gear method,motion equations of this mechanism including clearance,motor characteristic,torsion flexibility are developed and solved.The results show that clearance affects primarily the response on turret,and has little effects on the responses on rotary table.At the same time,the velocity fluctuation of motor shaft is not serious for the existence of inertia of reducer,and the high frequency of velocity fluctuation of camshaft is related with the torsion stiffness of shaft and the clearance between pairs.
文摘An integrated CAD/CAPP/CAM system modeling for Electric Discharge Machining (EDM) is constructed on the basis of an integrated engineering database. EDM feature objects are developed using the object oriented database provided by AutoCAD R14, and EDM feature modeling is realized in AutoCAD environments.
文摘In order to improve competitive ability of market, mo torcycle enterprises, special the small and middle sized ones must use IT to org anize social resource and adopt effective production mode, namely the dispersed networked design and manufacturing (DNDM), which was put forward and proved to b e one of vitality production modes in recent years. In responding to the new pro duction mode of VMCE, a dispersed networked CAD/CAM system (DNCADMS) of motorcyc le products should be developed. The objective of this paper is to investigate a new design and manufacturing mode and technical environment of motorcycle produ ction based on the concept of the DNDM for the small and meddle sized motorcycle enterprises. Because there are various CAx software systems, including differen t kinds of isolated CD, CAD, CAE, CAPP, CAM, PDM, and so on, are used at differe nt stages of the life period of motorcycle products under heterogeneous environm ents, to build a DNCADMS of motorcycle with high performance, some key issues, n amely the architecture of the DNCADMS, the integration of the isolated CAx softw are systems (CAxs), the data communication and exchange between these isolated s ystems and the data share problem under the dispersed heterogeneous database env ironment, should be solved well. For this, the idea we propose is the combinatio n of Web, CORBA, STEP and Java, which provides an effective mechanism to support the integration of isolated CAxs, and support communication and interoperabilit y among CAx systems. Each isolated CAx has been encapsulated respectively by a c ontainer, which is implemented by the ORBs and the IDL of the COBRA technology s tandard, and managed by the application index server. Each container is connecte d with the others by a local network or intranet/Extranet/internet and communica tes through network. For exchanging design and manufacturing information and kno wledge via a local network or the Internet, a commmerical product data translato r has been employed as a product data translating server to complete product dat a communication and exchange between the isolated CAx systems. And for solving t he data share problem under the dispersed networked heterogeneous database envir onment, the idea we propose is to build a meta-database for the native database s, which is a dispersed database, and links various native databases into a whol e logical database. For managing the meta-database, the database index server, a Java-based integrating mechanism, has been also put forward in this paper. Th e application and database index servers have been implemented with Java lan guage. Moreover, the native data base and knowledge base related to each isolate d CAx are be integrated into a dispersed database system by a meta-base.
文摘In this paper, a 'free surface intersection' algorithm is presented. This algorithm consists of two main stages: caculation of initial intersection points and tracing along an intersection curve. This procedure is valid for any parametric bicubic splint surface patch with a'convex hull', or a patch lies within the conwx hull of the control points.
文摘The purpose of this study was to evaluate and compare the microleakage and marginal discrepancy of ceramic crown-copings fabricated by three different CAD/CAM systems. Material and methods: Thirty extracted premolars were prepared for complete all-ceramic crowns with: total convergence 10-degree, 2 mm occlusal reduction, 4.5 mm height, 1.3 mm circular reduction and chamfer marginal preparation. They were divided into three groups and each group (n = 10) received a ceramic crown-coping fabricated by one of three CAD/CAM systems: Procera, KaVo Everest and Cerec inLab. The copings were cemented with Panavia F 2.0. After thermal cycling, the teeth were immersed in 2% basic fuchsine dye for 24 hours. Microleakage was scored using a five-point scale and evaluated under a stereomicroscope at ×18. Marginal discrepancies were assessed with scanning electronic microscope at ×150, with measurements at 50 different points. Data were subjected to a chisquare test, Kolmogorov-Smirnov test and using Rho Spearman’s correlation test (P 0.05). No significant differences were found in marginal discrepancies for the Procera (62.58 ± 8.98 μm) and KaVo Everest systems (65.54 ± 18.56 μm), (P = 0.941). Significant differences were found for Cerec inLab (132.18 ± 27.75 μm) compared with Procera and KaVo Everest (P = 0.0001). No correlation between the marginal discrepancies and microleakage for the three CAD/CAM crown-copings systems. Conclusions: Cerec inLab CAD/CAM crown-copings showed significantly higher values for microleakage and marginal discrepancy in comparison with Procera and KaVo Everest CAD/CAM crown-copings.
文摘How CAD design and simulation tools can assist in developing vacuum circuit breaker （VCB） in general is demonstrated. The electric field calculation has been widely utilized for electrical insulation design of VCB. ADAMS is applied in dynamic simulation to fulfill the complex calculation of mechanical characteristics. Satisfactory simulation results can be obtained by iteratively refining parameters of the model, and it is shown that this scheme can be used to provide a good basis for optimum design of VCB.
文摘This paper introduces a domestically developed CAD/CAM system,CAX,which is able to meet the needs of small and medium sized enterprises.Firstly,the motivations and principles for the developing of the system are presented.Then,the functions and features of CAX are described.In the 3rd section,the algorithms for generating blending surfaces with both constant radius and variant radii are detailed.Six color plates showing the applications of CAX are included in section 4.Finally,dis- cussed are some enhancements being added to CAX in th future.
文摘目的:观察微创超薄与计算机辅助设计与制造(Computer Aided Design/Computer Aided Manufacturing,CAD/CAM)全瓷贴面修复前牙间隙的美学效果及对口腔菌群微环境的影响。方法:选取笔者医院2023年2月-2025年2月收治的94例(共135颗患牙)前牙间隙患者为研究对象,采用随机数字表法分为两组。微创组47例(67颗患牙),采用微创超薄贴面修复;研究组47例(68颗患牙),采用CAD/CAM全瓷贴面修复。比较两组患者炎症反应、口腔菌群微环境、牙体美观度、修复效果及并发症发生率。结果:治疗后1个月,研究组肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、白细胞介素-1β(IL-1β)水平低于微创组(P<0.05);研究组牙卟啉单胞菌、具核梭杆菌、伴放线放线杆菌数量均低于微创组(P<0.05)。治疗后6个月,研究组红色美学指数评分(Pink Esthetic Score,PES)、改良版美国公共卫生服务(United States Public Health Service,USPHS)评分均高于微创组(P<0.05)。研究组并发症发生率低于微创组(P<0.05)。结论:CAD/CAM全瓷贴面修复前牙间隙修复效果和安全性良好,不仅对患者口腔菌群微环境影响较小,有利于减轻修复后炎症反应,还能明显提升牙体美观度。
基金jointly supported by the National Key Research and Development Program of China [grant number 2022YFF0802004]the Excellent Youth Natural Science Foundation of Jiangsu Province [grant number BK20230061]the Joint Open Project of KLME&CIC-FEMD[grant number KLME202501]。
文摘This study investigated the impacts of key parameters in CAM6's deep convection and cloud physics schemes on the simulation of summer-mean precipitation over East Asia through conducting perturbed parameter ensemble(PPE)experiments.Utilizing the experimental platform of CAM6,a suite of 128 PPE simulations spanning 19792014 were generated through simultaneously perturbing 12 selected parameters.Using EOF analysis,this study firstly extracted the first two leading modes of the precipitation simulation biases.The authors further pinpointed the most critical parameters that have the most influential effects on the precipitation simulation biases,through conducting generalized linear model analysis.The first leading mode of precipitation simulation biases is primarily influenced by parameters from the cloud physics scheme,including the linear effects of dcs and eii,and the nonlinear effect of rhminl*dcs.These parameters influence the simulated total precipitation(PrecT)mainly by altering the large-scale precipitation(PrecL).The second leading mode is predominantly governed by the convection scheme parameter dmpdz,reflecting a competition between the changes in convective precipitation(PrecC)and PrecL in response to variations in dmpdz.An increase in dmpdz induces decreased PrecC and increased PrecL in East Asia,and both of the changes collectively shape the ultimate PrecT response to the adjusted dmpdz.Lastly,it is noteworthy that the nonlinear effect due to the interaction among parameters warrants attention when concurrently adjusting multiple parameters,and the precipitation biases from the PPE simulations resemble those identified through EOF analysis on the AMIP simulations,implying our findings may provide potential reference for other AGCMs.
