Method for assessing composite space type face geometric error

Abstract

The invention relates to a method for evaluating geometrical error of a compound spatial moulding surface, belonging to the field of mechanic parts geometrical error evaluation. The method comprises the following steps: (1) a three-dimensional CAD model of a work piece to be evaluated is read and an ideal work piece model is reconstructed; (2) geometrical data of the work piece to be evaluated is measured to obtain the coordinate information of each measured point; (3) the error value of the measured moulding surface is calculated according to the geometrical error evaluation items of the work piece to be measured including spatial straightness accuracy, cylindricity and punch combination compound position; and (4) the error evaluation result is compared with the read ideal work piece model for analyzing, the processing error information is displayed by adopting colour cloud points, and the error evaluation report is obtained finally. The invention, by the approaching process for constructing minimum zone, realizes fast and accurate evaluation on the geometrical error of the compound spatial moulding surface.

Description

technical field [0001] The invention belongs to the field of geometric error evaluation of mechanical parts, and relates to a geometric error evaluation method. Background technique [0002] The error models and geometric error evaluation algorithms used in the existing geometric error evaluation systems are mostly approximate algorithms, the implementation process is complex, and there are problems of too many iterations or excessive calculations to varying degrees. The definition does not match, and the shape error value is often overestimated, resulting in the false rejection of qualified products. Or it is only limited to giving the normal deviation value of a certain number of discrete points on the space profile, but fails to give the geometric error information of the overall profile. After measuring the workpiece with advanced measurement technology and instruments, advanced shape and position error evaluation theory and precise algorithm are the key to obtain the a...

AI Technical Summary

Problems solved by technology

Scholars at home and abroad have proposed some optimization algorithms for different shape and position error items, but most of the existing evaluation algorithms use approximate error models and geometric error evaluation algorithms. The problem of too large, the evaluation standard does not match the definition of shape error in relevant standards, and the value of shape error is often overestimated, resulting in the wrong rejection of qualified products

[0004] Based on the above analysis, the main shortcomings of the current research work in related fields are: the lack of a geometric error evaluation system that can efficiently and accurately evaluate the composite space surface

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