| At present, the numerical control bend tube obtains the widespread application in the aviation manufacture domain. It's design and manufacture quality have very important influence to the integrity, the reliability of airplane and the engine organization. The NC bend tube welding jig is the key of the NC bend tube's quality.But now there are some shortcomings in the CAD modeling of aero NC bend tube and it's welding jig, such as poor quality of models, low efficiency of modeling, little design reuse and awful specification in models. To solve these problems, we summing-up a flow about the design and manufacture process of NC bend tube, and developing a CAD system for the NC bend tube welding Jig. The main jobs of this thesis are as followed:1) The frame of NC bend tube welding jig CAD system is proposed. Leading by the NC bend tube welding jig design flow, develop a series of tools in the CAD software platform, then construct the NC bend tube welding jig CAD system under the tools collection;2) Use the reverse technology of NC bend tube's modeling, Aim to the most general NC bend tube, reevaluation the bend tube's essential feature by using the vector transformation algorithm, and establish bend tube model above this foundation. Aim to the special model NC bend tube, use the modeling method that essential parameter drive product sample model;3) In the foundation that summing up a rule of optimized welding assembly underside of tube, develop the NC bend tube welding underside optimization design tool, then complete the optimization design united with two application methods: rotation method and the least squares method;4) Propose a design method of NC bend tube welding jig bottom base, then establish model storehouse according to the design rules, and endow the foundation model with assembly feature. Design knowledge is packaged with the idea of relationship among features to make assembly and part modeling conducted simultaneously;... |
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