Research On Standardization Of CATIA Drafting And Computer Aided Tolerance

As the extensive application of modern commercial CAD software, engineering drawing is now drawn by computers instead of hands, and the efficiency of design has a great improvement. Nowadays, CATIA is widely accepted and used in the domestic aviation companies because of its accuracy, safety, and reliability. But as a general CAD software, it can not meet all the needs of domestic aviation companies, for example: the drafting module of CATIA does not introduce the GB (National standard of China), so not all the annotations and symbols conform with GB; Besides, CATIA hasn't offer effective tools to aid tolerance design.This paper researches and develops software tools integrated with CATIA conforming to GB to mark symbols and aid tolerance design. The work is summarized as follows:1. The software functions are summarized based on the study of drafting module of CATIA and the need of company. With the Comparison of several technologies of CATIA secondary development, this paper established CAA as main development method and VBScript as a supplement, and the four-layer software architecture is also designed.2. Based on the encapsulated CAA-API classes, this paper redevelops the functions of drawing-setting, BOM, Technical Requirements and so on. The new developed functions conform to the GB and have higher degree of automation. So they can support the engineers to design the drawings quickly and efficiently.3. A computer aided tolerance (CAT) database is developed to support the tolerance inquire tool, fit design tool and shaft/hole tolerance marking tool. These tools are easy to manipulate and efficient.