The Assembly Size Establishment And Application Of The Road Map

With the rapid development of computer technology, great breakthrough andresplendent achievement have been made in CAD/CAM at present. But thedevelopment of an important part of mechanical product design andmanufacturing—computer aided tolerancing design has lagged behind themgreatly, it has become the bottleneck of their further development, which makesit necessary to do research on it. It is an important part in CAT field and of greatsignificance in engineering to utilize computer aid engineers to make sure of thereasonable dimensioning mode, complete the automatic dimensioning of partsand realize tolerance analysis and comprehensive reasonably.So,the concept ofthe schematics of assembly dimension route has been put forward, whichcombined advantages of the graphics expression intuitive and text descriptionaccurate, using the text graphics to ensure the reasonable dimensioning mode ofthe parts. Moreover, after the path diagram has been confirmed, a mode systemof mounting dimensions can be established for the target sizes in the ensemble,and a complete model of total correlative mounting dimensions can be obtained.Under the drive of the entire target sizes and the tolerances, the dimensions andthe tolerances of all the components can be solved so that the demands ofcomputer-aided design of tolerance and parameterization can be better met.In this paper, tasks has been accomplished as follows:(1)Being defined the name method of the element and dimension in parts,the concept of the target size and its select principle.(2)Put the computer aided tolerancing design problem to ascend to theassembly levels, Based on "finding the shortest path" and "giving high-precisionpriority", two essentials of establishing path diagrams are put forward. Throughestablishing The Schematics of Assembly Dimension Route to ascertain thereasonable dimension mode of parts.(3)Through establishing The Assembly Dimensioning Model to implementthe reasonable tolerance analysis and synthesis of parts, and realized theparameter of dimension and tolerance. (4)Based on VB.net2005software development environment, using ActiveXtechnique provided by CAD, the corresponding system has been developed.(5)Use the example to introduce the entire realizing process of the automaticdimensioning technique.