Study On Automatic Generation Of Assembly Dimension Chain And Its Realization Based On Pro/E

Three-dimensional CAD softwares have found their wide application in the manufacturing industry. But the application of Computer Aided Tolerancing (CAT) based on three-dimensional CAD softwares is not adaptive with them. Now the study of Computer Aided Tolerancing includes tolerance representation, tolerance analysis and tolerance synthesis. The tolerance analysis and tolerance synthesis base on the generation dimension chain. So, the study of generation dimension chain is necessary.In this paper, automatic generation principle of assembly dimension chain and its realization based on Pro/E have been studied. By using the application development tools (Pro/Toolkit), VC++ and ACCESS database, an assembly dimension chain automatic generation system based on Pro/E has been developed. The dimension and assembly constraints information is acquired from the 3D assembly model. The assembly dimension chain is generated automatically. Through the above study, results have been gotten in this paper are as following:(1) Automatic generation principle of the assembly dimension chain is presented based on Pro/E platform. Firstly, the closing loop is specified in the 3D assembly model by user. Secondly, the assembly constraint types and the features that take part in the constraints are acquired. Thirdly, the assembly constraints chain is generated by linking the closing loop after deleted the constraint types and the features that are independent of the closing loop. Lastly, the assembly dimension chain is generated when the requisite feature dimensions are acquired.(2)A database for assembly dimension chain is set up. The information is expressed by means of ACCESS database for saving and reading conveniently. The database structure and the relations between the data are given.(3)A prototype system of Computer Aided assembly dimension chain generating automatically is developed based on Pro/E platform. The system bases on Pro/E platform and uses VC++ and Pro/Toolkit as application development tools. The system can generate the assembly dimension chain automatically.