A method for measuring the inner surface of narrow and deep cavity of castings based on 3D scanning

Abstract

The invention provides a casting narrow deep cavity inner surface measuring method based on three-dimension scanning. The method comprises the steps that a theoretical module is structured to a theoretical surface associated with casting dimensions by using three-dimension scanning equipment; a typical point is selected in the inner surface of the casting; a marked ring is arranged on the outer surface of the casting, the center of a circle of the marked ring is located on a straight line which is perpendicular to axis of rotational symmetry of the casting in an intersecting mode and pass through the typical point; three-dimension scanning is carried out on the casting; a contract color ribbon is adjusted, obvious differences exist in three-dimension scanning point cloud of the outer surface of the casting in the marked ring and a ring inner area; the distance from center of the circle of the marked ring to the theoretical surface is calibrated; the wall thickness of the casting in theposition of the center of the circle of the marked ring is measured; and the distance from the typical point to the theoretical surface is calculated by using the distance and the wall thickness of the center of the circle of the marked ring to the theoretical surface. According to the casting narrow deep cavity inner surface measuring method based on the three-dimension scanning, the casting narrow deep cavity inner surface typical point and the outer surface are combined accurately by using the marked ring, and efficient and rapid measurement of the casting inner surface dimensions is realized.

Description

technical field [0001] The invention relates to a method for measuring the inner surface of a narrow and deep cavity of a casting based on three-dimensional scanning, and belongs to the technical field of casting detection. Background technique [0002] With the continuous promotion and application of 3D scanning technology, the size inspection of parts is becoming faster and more comprehensive, especially for the inspection of complex spatial surfaces, which has incomparable advantages compared with other inspection methods. However, limited by the principle of 3D scanning technology, there are scanning blind areas in the inner surface of narrow and deep cavities, and the surface size data of these parts cannot be collected. Three-dimensional scanning has been unable to make breakthroughs in the measurement of the inner surface of narrow and deep cavities. [0003] The measurement of the inner surface of the narrow and deep cavity of traditional castings is mainly divided ...

AI Technical Summary

Problems solved by technology

However, limited by the principle of 3D scanning technology, there are scanning blind spots on the inner surface of narrow and deep cavities, and the surface size data of these parts cannot be collected.

Three-dimensional scanning has been unable to make breakthroughs in the measurement of the inner surface of narrow and deep cavities

For direct measurement, it is necessary to destroy the casting body, convert the narrow and deep cavity into an open surface or a small segmented cavity, and then measure it, which cannot directly reflect the size and dimensional changes of other castings; indirect measurement, due to the low dimensional accuracy of the casting surface, has no The regular smooth surface is used as a reference, and the outer surface needs to be measured after machining as a whole. The measurement cycle is long and the feedback lags behind, so it cannot guide the production of castings in time.

[0004] Aiming at the scanning blind area of ​​3D scanning on the inner surface of the narrow and deep cavity, especially the inner surface of the narrow and deep cavity of the casting, a rapid measurement method is proposed to solve the problem of rapid detection of the circumferential dimension of the inner surface of the narrow and deep cavity of the casting

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