Device and method for detecting roundness and straightness of cylindrical holes by coaxial light

Abstract

The invention relates to a device and a method for detecting roundness and straightness of cylindrical holes by coaxial light and belongs to the technical field of optical detection. The prior art is low in detection precision and narrow in detection range and possibly causes damage to the surface of a cylindrical hole being detected. The device is disposed between a detecting laser source and a camera. An iris diaphragm, a light barrier ring, a conical lens and a frosted glass imaging screen are axially arranged in sequence. The bottom of the conical lens faces to the light barrier ring and is provided with a central through hole. The method includes: the cylindrical hole to be detected is located between the conical lens and the frosted glass imaging screen and is axial with coaxial light; the distance of hollow beams from outer wall to inner wall is changed by regulating the iris diaphragm; the hollow beams emerging from a conical surface of the conical lens converge and reflect once at different sectional positions of the cylindrical hole being detected, and light ring images for each section are present on the frosted glass imaging screen successively; the images are acquired by the camera and processed by a computer, roundness of different sectional positions of the cylindrical hole to be detected is calculated first by the least square circle method, and straightness of the cylindrical hole is obtained then.

Description

technical field [0001] The invention relates to a device and method for detecting the roundness and straightness of a cylindrical hole with coaxial light. Under the premise of non-contact and non-destructive, the concentric laser beam formed by a conical lens with a small hole in the center is used to detect the cylindrical hole of a part in real time. The roundness and straightness belong to the field of optical detection technology. Background technique [0002] In the field of precision or ultra-precision machining, how to control the roundness and straightness of the column hole is related to the fit and rotation accuracy of the parts, and is directly related to friction, vibration, noise, etc., which in turn affects the service life and energy consumption of the parts. Therefore, it is necessary to accurately evaluate the roundness and straightness of the column hole. The evaluation results not only provide the basis for the acceptance of the parts, but also help to imp...

AI Technical Summary

Problems solved by technology

However, the detection scheme has its shortcomings: one is that the scheme is only suitable for the detection of large-diameter inner holes, and if the inner hole diameter is smaller, the measuring trolley cannot enter; the other is that the measuring trolley does not have its own dedicated and precise track. The walking roll angle and the shape error of the measured workpiece will reduce the detection accuracy; the third is that the measuring trolley may scratch the inner surface of the measured workpiece during the walking process

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