Research On Axis Straightness Inspection System Of Deep Hole Parts

Deep hole parts are widely used in military industry,instrument and energy exploration and other important fields.In order to better evaluate the quality of deep hole parts,it is often necessary to test the straightness of its axis line and straighten the unqualified parts in time.However,the traditional detection methods commonly used at present are mostly limited by the characteristics of large aspect ratio and small inner hole space of deep hole parts,so the detection is more difficult and the accuracy is not high.In order to accurately measure the axis straightness of deep hole parts and meet the needs of related industries,this paper carries out in-depth research on the detection method of axis straightness of deep hole parts.This paper takes the small-caliber barrels in deep-hole parts as the main research object.Based on the photoelectric detection method,aiming at the problem that the inner hole of the barrel is too small to be built-in photoelectric measuring element,a method for detecting the axis straightness of deep hole parts with external measuring element is proposed,and a corresponding straightness detection system is designed to complete the measurement work.Firstly,the straightness error measurement model is established according to the proposed detection method,and a set of axis straightness detection system of deep hole parts is designed,and the composition and working principle of the system are analyzed and explained.Secondly,using 3D modeling software to design the overall structure of the straightness detection device,including traction mechanism,clamping mechanism and optical imaging system,etc.,and completed the selection of some hardware;At the same time,combined with the specific characteristics of the inner hole surface of the tested part,a versatile self-adaptive centering device with a cross-shaped light hole is designed,which can avoid interference with the spiral rifling in the inner hole of the gun barrel;Then,using the calibration plate calibration method combined with HALCON software,the camera calibration operation is completed,and the internal and external parameters of the camera are obtained.After preprocessing the collected light spot image,the center point extraction method based on the image skeleton is used to obtain the center point coordinates of the cross-shaped light spot;Aiming at the problem that the center line of the centering mechanism and the axis line of the measured part are not strictly collinear,the extracted center point coordinates are corrected according to the rotation angle and coordinate transformation principle,so as to reduce the influence of assembly error.Finally,combined with the secondary development of the camera SDK,the software system of straightness detection was designed using the Visual Studio 2019 software development platform,and each functional module of the software was introduced.A large number of experiments have been carried out on the established experimental platform.The experimental results show that the straightness detection method proposed in this paper has the advantages of simple operation,high detection accuracy and good repeatability,which can meet the required detection requirements.In addition,the detection system can detect the axis straightness of the deep hole parts within the inner diameter of 25-35 mm,which has certain practical application value.