Research Of Computer-aided Assembly Tolerance Design Based On Three-dimensional CAD Model Module Division

The tolerance of the product’s design stage directly affects the product assembly, theerror of assembly is caused by the error accumulation in the process of assemebly. ComputerAided tolerance design (Computer Aided Tolerancing, referred to as "CAT) is one of the keytechnology of CAD/CAM integration, applying the technology of product assembly stage,could well reduce the cost of manufacturing and assembly phase, and comparing with thetraditional manual assembly, improving the accuracy, thus improving product quality.In the process of digital assembly structure design, as a result of the general CADplatform is not for a specific product digital assembly module structure design, assemblystructure design method in the application process is too scattered, design experience andknowledge to the reasonable reference and reuse, so the designer will not be able to better andfaster use of the experience and knowledge in terms of product design and development andimprovement.This paper aims to chart a three-dimensional model of the assembly dimension chain beautomatically generated based on tolerance analysis and tolerance synthesis technologyresearch to improve the usefulness of virtual assembly simulation.Through the analysis of theassembly information model of CAD environment, make clear the structure of the assemblymodel and data information; Build the assembly dimension chain oriented database, use CreoParametric TOOLKIT secondary development technique, extract information from assemblymodel and stored in the database, realize the data conversion from the3d CAD model tothe database; On the basis of the assemble database, this paper puts forward the strategies,methods of automatic generation of assembly dimension chain and the basic process, the useof innovative community structure discovery method in the complex network of modulepartition of assembly model, realized the computer aided tolerance analysis of complexassembly, combined with the monte carlo algorithm implementation of tolerance design andtolerance synthesis.In vs2008development platform, this paper using creo secondary development tools creoParametric TOOLKIT, integrated in creo tolerance design system is developed, the systemincludes automatic generation of assembly dimension chain, tolerance optimization designand assembly tolerance analysis three modules; discusses Tolerance Design System the basicfunction and use of the overall structure, and examples illustrate various modules of thesystem.