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
The design solutions for breadth cam mechanism was presented. The main topics of the shape design for breadth cam was to calculate the coordinate at each contact point to determine the cam profile. The proposed method...The design solutions for breadth cam mechanism was presented. The main topics of the shape design for breadth cam was to calculate the coordinate at each contact point to determine the cam profile. The proposed method according to velocity and geometric relationships of instant velocity centers can easily determine each contact point at any instant moment. The cam profile was defined by contouring of the contact points. And also a program was developed by using Microsoft Visual C++ program,which can quickly and easily draw a 2D cam profile through the displacement diagram. Finally,the program was used to confirm the accuracy on the breadth cam profile design by computer animation graphically.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.
基金Work supported by the Second Stage of Brain Korea 21 Projects
文摘The design solutions for breadth cam mechanism was presented. The main topics of the shape design for breadth cam was to calculate the coordinate at each contact point to determine the cam profile. The proposed method according to velocity and geometric relationships of instant velocity centers can easily determine each contact point at any instant moment. The cam profile was defined by contouring of the contact points. And also a program was developed by using Microsoft Visual C++ program,which can quickly and easily draw a 2D cam profile through the displacement diagram. Finally,the program was used to confirm the accuracy on the breadth cam profile design by computer animation graphically.
