A model-exchange method based on feature between isomerous CAD systems is put forward in this paper.In this method,CAD model information is accessed at both feature and geometry levels and converted according to stand...A model-exchange method based on feature between isomerous CAD systems is put forward in this paper.In this method,CAD model information is accessed at both feature and geometry levels and converted according to standard feature opera- tion.The feature information including feature tree,dimensions and constraints,which will be lost in traditional data conver- sion,as well as geometry are converted completely from source CAD system to destination one.So the transferred model can be edit- ed through feature operation,which cannot be implemented by general model-exchange interface.展开更多
The TangShan Research Institute of Group Technology has been engaged in the develop- ment of GT for the light industry machinery building factories since 1980.Under its overall supervision more than 8 factories have a...The TangShan Research Institute of Group Technology has been engaged in the develop- ment of GT for the light industry machinery building factories since 1980.Under its overall supervision more than 8 factories have applied GT to drawing control and process planning,while 4 of them reorga- nized their machine shops into GT cells and the throughput capabilities were raisd immediately by 15 to even 49%. Since the existing GT coding systems predict only the global characteristics of machine parts,their application alone is unable to transfer all the information needed for the CAD/CAM integration in a CIM environment.From the very beginning of 1989,we started to study the feasibility of introducing concepts of Functional Form Features into GT codes.Based on the exhaustive study of nearly 100,000 part drawings from machineries for making pottery and porcelain appliances,cigarette,paper pulp, glass bottles,plastics moulding,beer and beverage filling etc.,a new GT/FFF coding system was worked out and a corresponding set of standard drawings assembled from FFF primitives Was formulat- ed which can cover up to 65—75% of existing parts from light industry machineries.FFF based GT codes greatly facilitate the standardization control of released drawings,accelerate the engineering de- sign and process planning,and certainly will play an important role in the future CIM organization.展开更多
A design-with-feature system of rotational parts has been linked with a process planner bydirect file transfer. Although both systems take the feature-based approach, inconsistency exists inthe way of defining correla...A design-with-feature system of rotational parts has been linked with a process planner bydirect file transfer. Although both systems take the feature-based approach, inconsistency exists inthe way of defining correlation between adjacent form features, the representation schema of featurehierarchies, the way of dimensioning and tolerancing etc. Such discrepancies are outlined in this pa-per and expected to be taken into consideration in working out an improved Integrated Product Infor-mation Model for the CIM and concurrent engineering environment.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
By adopting the parameterized designing method of f ea ture assembled and feature unit, for the feature of non-conventional type parts , such as welding box and bearer, by use of Visual C++ and AutoCAD a s soft tools,...By adopting the parameterized designing method of f ea ture assembled and feature unit, for the feature of non-conventional type parts , such as welding box and bearer, by use of Visual C++ and AutoCAD a s soft tools, the system can successfully carry out the basic function of featur e assembled, the processing of two-dimensional figure, the building of three-d imensional feature, the automatic producing of technical papers, and so on. The thoughts and design methods of this system can be served as the preference to CA D/CAPP integrated for othernon-conventional type parts. For non-conventional parts, its feature is too much, so the parameter is much. By adopting interactive entry for graphic parameter, under the control of main c ontrol module, through inputting the feature parameter and calling the feature g raphic unit, the function for modeling is completed. To reduce input of feature parameter, the description of position feature is adopted in the feature descrip tion of non-conventional parts, that is, fix position is constraint through str ucture and dimension of non-conventional parts. In such a manner, the assembled process has been transformed the coordinate conversion process, and this is ver y important in the production of three-dimensional graphics. In the one hand, b y calling the feature of parts in the library of feature-graphic unit, the two -dimensional DXF file and three-dimensional SCR file are automatically produce d in AutoCAD. On the other hand, by calling the rules and standard operational s equences in the technologic knowledge base, through inferring of inference engin e, the assembled sequence of non-conventional parts and welding sequences are a utomatically produced. The two aspects constitute overall design philosophy for system. So the CAD/CAPP integration of feature-assembled for non-conventio nal parts are completed. The principle of dividing feature is based on the thought of group technology, t hat is, according to the function feature of parts. The feature-assembled p arameterized design method is to divide the parts into many feature-units, acco rding to the structure, function, and secondary feature, and the each unit is in teractively produced, so the whole part is assembled gradually. At the same time , to display the sequences which deviser chooses varied features, hidden feature code is adopted. The feature-unit parameterized design method is to assemble dimension, margin tolerance and fitting-in, and surface roughness into one unit that it becomes a fixed structure. However big it is, it could be added to or taken off like a ba sic feature-unit.By adopting above-mentioned methods, the module of parts is e stablished. Under the integrated environment, according to basic construct of expert system, CAPP system is made up of three sectionsdynamic database (document-view ), knowledge library and inference engine. Dynamic database is served as storing initialized and middle information as well as ultimate design result. The knowl edge library is composed of static database, rule set, and standard welding proc ess library.展开更多
A brief discussion of the content and methodology of STEP is given, and STEP based strategies for CAD/CAPP information integration is pointed out. A STEP based feature technology in which a three layer feature defini...A brief discussion of the content and methodology of STEP is given, and STEP based strategies for CAD/CAPP information integration is pointed out. A STEP based feature technology in which a three layer feature definition is included is discussed, the content of feature information is analyzed and a stratified CAD feature library is shown. On these bases, a commonly shared part information model is proposed. The architecture of the integrated CAD/CAPP system is presented.展开更多
The information integration of CAD/CAPP is one of the crucial techniques in CIM. Thispaper desicribes an integrated CAD/CAPP system which is implemented by connecting MPIM to BR-CAPP via an interface for data exchange...The information integration of CAD/CAPP is one of the crucial techniques in CIM. Thispaper desicribes an integrated CAD/CAPP system which is implemented by connecting MPIM to BR-CAPP via an interface for data exchange between them. The data exchange between MPIM and BR-CAPP is accomplished through STEP neutral file.展开更多
基金Supported by Science&Technology Sponsoring Project of Ministry of Education(105161)
文摘A model-exchange method based on feature between isomerous CAD systems is put forward in this paper.In this method,CAD model information is accessed at both feature and geometry levels and converted according to standard feature opera- tion.The feature information including feature tree,dimensions and constraints,which will be lost in traditional data conver- sion,as well as geometry are converted completely from source CAD system to destination one.So the transferred model can be edit- ed through feature operation,which cannot be implemented by general model-exchange interface.
文摘The TangShan Research Institute of Group Technology has been engaged in the develop- ment of GT for the light industry machinery building factories since 1980.Under its overall supervision more than 8 factories have applied GT to drawing control and process planning,while 4 of them reorga- nized their machine shops into GT cells and the throughput capabilities were raisd immediately by 15 to even 49%. Since the existing GT coding systems predict only the global characteristics of machine parts,their application alone is unable to transfer all the information needed for the CAD/CAM integration in a CIM environment.From the very beginning of 1989,we started to study the feasibility of introducing concepts of Functional Form Features into GT codes.Based on the exhaustive study of nearly 100,000 part drawings from machineries for making pottery and porcelain appliances,cigarette,paper pulp, glass bottles,plastics moulding,beer and beverage filling etc.,a new GT/FFF coding system was worked out and a corresponding set of standard drawings assembled from FFF primitives Was formulat- ed which can cover up to 65—75% of existing parts from light industry machineries.FFF based GT codes greatly facilitate the standardization control of released drawings,accelerate the engineering de- sign and process planning,and certainly will play an important role in the future CIM organization.
文摘A design-with-feature system of rotational parts has been linked with a process planner bydirect file transfer. Although both systems take the feature-based approach, inconsistency exists inthe way of defining correlation between adjacent form features, the representation schema of featurehierarchies, the way of dimensioning and tolerancing etc. Such discrepancies are outlined in this pa-per and expected to be taken into consideration in working out an improved Integrated Product Infor-mation Model for the CIM and concurrent engineering environment.
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By adopting the parameterized designing method of f ea ture assembled and feature unit, for the feature of non-conventional type parts , such as welding box and bearer, by use of Visual C++ and AutoCAD a s soft tools, the system can successfully carry out the basic function of featur e assembled, the processing of two-dimensional figure, the building of three-d imensional feature, the automatic producing of technical papers, and so on. The thoughts and design methods of this system can be served as the preference to CA D/CAPP integrated for othernon-conventional type parts. For non-conventional parts, its feature is too much, so the parameter is much. By adopting interactive entry for graphic parameter, under the control of main c ontrol module, through inputting the feature parameter and calling the feature g raphic unit, the function for modeling is completed. To reduce input of feature parameter, the description of position feature is adopted in the feature descrip tion of non-conventional parts, that is, fix position is constraint through str ucture and dimension of non-conventional parts. In such a manner, the assembled process has been transformed the coordinate conversion process, and this is ver y important in the production of three-dimensional graphics. In the one hand, b y calling the feature of parts in the library of feature-graphic unit, the two -dimensional DXF file and three-dimensional SCR file are automatically produce d in AutoCAD. On the other hand, by calling the rules and standard operational s equences in the technologic knowledge base, through inferring of inference engin e, the assembled sequence of non-conventional parts and welding sequences are a utomatically produced. The two aspects constitute overall design philosophy for system. So the CAD/CAPP integration of feature-assembled for non-conventio nal parts are completed. The principle of dividing feature is based on the thought of group technology, t hat is, according to the function feature of parts. The feature-assembled p arameterized design method is to divide the parts into many feature-units, acco rding to the structure, function, and secondary feature, and the each unit is in teractively produced, so the whole part is assembled gradually. At the same time , to display the sequences which deviser chooses varied features, hidden feature code is adopted. The feature-unit parameterized design method is to assemble dimension, margin tolerance and fitting-in, and surface roughness into one unit that it becomes a fixed structure. However big it is, it could be added to or taken off like a ba sic feature-unit.By adopting above-mentioned methods, the module of parts is e stablished. Under the integrated environment, according to basic construct of expert system, CAPP system is made up of three sectionsdynamic database (document-view ), knowledge library and inference engine. Dynamic database is served as storing initialized and middle information as well as ultimate design result. The knowl edge library is composed of static database, rule set, and standard welding proc ess library.
文摘A brief discussion of the content and methodology of STEP is given, and STEP based strategies for CAD/CAPP information integration is pointed out. A STEP based feature technology in which a three layer feature definition is included is discussed, the content of feature information is analyzed and a stratified CAD feature library is shown. On these bases, a commonly shared part information model is proposed. The architecture of the integrated CAD/CAPP system is presented.
文摘The information integration of CAD/CAPP is one of the crucial techniques in CIM. Thispaper desicribes an integrated CAD/CAPP system which is implemented by connecting MPIM to BR-CAPP via an interface for data exchange between them. The data exchange between MPIM and BR-CAPP is accomplished through STEP neutral file.
