Reverse Engineering Key Technologies And The Error Factor Analysis

As an important means to develop new products and digest,absorb advanced manufacturing technology,reverse engineering can modify,re-design prototype through CAD model of reconstructing product that provide a digital prototype for re-design products as well as innovative design.Through reverse engineering,on the basis of digest,absorb advanced technologies,we can construct,control our product development design technology and to do product innovative design,that is the only way to improve China's manufacturing industry.This paper has researched the key technology of,reverse engineering concluding physical surface data acquisition technology(physical prototype digital technology) and product modeling technology(CAD model reconstruction technology),done error factor analysis.First of all analyze physical data acquisition method concluding contact method and non-contact method and various measurement equipments,we choose measurement methods and equipment according to different measurement targets and measurement needs.Selecting Germany ATOS optical measurement equipment to scan and access the data cloud of auto rearview mirror, then use relative software to do point cloud pretreatment,and we can see Uniform grid method can be better streamlined point cloud data,and the relevant parameters setting in the actual operation influences much to the accuracy of point cloud data.Research principle of point cloud data alignment and three benchmarks alignment,compare different alignment methods.Through practical application to compare error between various alignment methods,we can select different point cloud data alignment method on the basis of the positional accuracy of the different requirements.Research on point cloud data processing method concluding data smoothing and data streamlining,use three different methods of filtering point cloud data to do data smoothing,compare several point cloud data streamlining methods, and at last identify uniform grid method to do point cloud data streamlining processing.Research on the whole process from pretreatment point cloud to surface reconstruction,analyze error model and surface quality.Using mathematical B-spline curves approximation and lofting method to reconstructed surface,splice a number of surface slices after sub-surface fitting.Use professional software UG/Imageware to complete the reconstruction of point cloud data to curves and surfaces,and make comparison,analyze the error resource,and combine with the evaluation standard of surface quality to value the surface modeling effectiveness with methods such as reflection method,high light method and uniform illumination method.Make the summarization that the precision control must consider the factors such as efficiency,technical competence and innovative design.Research on reverse engineering error model,and ultimately select lofting method to construct surface which face's curvature changes slowly,make adjustment to control the overall error no more than 0.5mm to meet modeling requirement.Consider precision adjustment must give attention to work efficiency balance,manufacturing technical capability and influence of innovative design.Give the practical project from Yunnei-power ltd. to further clarify the actual application of the key technologies of reverse engineering.