Research On Valve Body Design Technology For Reverse Engineering

Valve body has free surfaces and lumen. The shape of lumen is one of factors which affect liquid flow velocity, flow rate and cause vibration, noise. But the geometry shape is irregular, called free surface, so it is difficult to be exactly expressed by two -dimension geometry graphs and mathematic formula, this always is a bottleneck difficulty to design valve body. In this condition, applying reverse engineering technology to complicated valve body design seems to be one tendency adapting to the development of modern manufacture technology.This thesis researches valve body model design applying reverse engineering technology.Firstly, research the key technology of reverse engineering. (1) Research the theory and methods of point clouds alignment, and validate the theory by example. (2) Research uniformity sampling method, chord warp sampling method, space sampling method, and test point cloud condense capability of the methods in different parameters. (3) Aim at the modern condense method exist the feature points losing, bring forward self-fitting point cloud condense method, and analyse the arithmetic capacity by testing.Secondly, research new technics of rapid exploring valve body. Use silicon rubber copy valve inside, apply reverse engineering technology to measure valve outside and silicon rubber outside. Adopt positive and reverse composition technology, use reverse software to establish valve free surfaces, use positive software to establish valve formula surfaces. In the end, assemble lumen CAD model and valve outside model, acquire the whole three- dimensional CAD model.Thirdly, discuss the possible error in the course of complicated valve body design based on reverse engineering, then modify the model according to prototype, symmetry, assembly, finite drawing and sample modification.This paper applys reverse engineering theory and methods can accurately establish complicated entity, these theory and methods can be applied in the objects with similar structure features.