Digital Measurement And Reverse Design Of The Complex Box

With the rapid development of economy and society,the requirements on the shape design,manufacturing quality and inspection accuracy are more and more strict in the industrial fields.The technology of digital measurement and reverse design has been widely used in the production.The digital measurement,design and manufacturing which constitute the closed-loop digital chain of product manufacturing are more and more closely linked.The technology of digital measurement and reverse design is playing an increasingly important role in improving productivity and ensuring product quality.The key technologies of the digital measurement and reverse design for the complex box were studied such as digital measurement method,data processing method,surface reconstruction method and model precision evaluation.The structural features of the complex box were analyzed.The external surface of the box was measured with the 3D laser scanning based on the transfer station measurement.A new digital measurement method of box cavity based on the plaster model was proposed.The method based on feature point matching was used to match the point cloud of box external surface and the point cloud of the cavity and the whole point cloud data of the box surface was acquired.The generating causes of the noise point were analyzed.The denoising and simplification of the point cloud were researched.A fast k nearest neighborhood search method based on spatial cell was proposed for denoising of the box point cloud and a better denoising effect was obtained.A variety of point cloud simplification methods were analyzed.A composited method combining the curvature sampling and the uniform sampling was proposed for simplifying the point cloud data of the complex box and the certain effect was gained.The curve fitting modeling and surface fitting modeling were studied.The smoothing methods of curve and surface were studied and analyzed.The 3D CAD model of the box was constructed according to the surface point cloud data of the box.Then the method for point-to-surface minimum distance based on grid method was adopted to obtain the error results of complex box.Finally the error results were analyzed and the accuracy evaluation of the model was completed.The 3D digital model of the complex box was constructed and the accuracy evaluation of the model was completed.The study results can be beneficial to theoptimization design of the box casting mould and a useful reference can be provided for the casting manufacture.