电极圆锥内螺纹的无损检测

将CT技术和图像处理技术相结合,提出了电极圆锥内螺纹的无损检测方法。目前普通螺纹常用的测量方法大多为接触测量,有关文献介绍了非接触检测方法,但它们仅限于圆柱内螺纹,圆锥内螺纹的图像处理及非接触测量未见报道。从CT技术入手,探讨了电极圆锥内螺纹的图像检测方法,即在一个系统中实现对工件内部缺陷的检测及几何参数的测量。通过使用图像预处理、阈值选取及二值化、边缘检测及提取等方法,提取了螺纹轴截面齿形轮廓,并对不同处理方法进行了比较。使用自编程序测量计算了内螺纹的螺距、牙型角和锥角,测量精度分别达到了0 03mm,0 24°和0 02°。分析了误差产生的原因。理论分析及实验结果表明该方法正确可行。

Non-damage measurement on internal taper thread of electrode

In order to perform non-damage measurement on internal taper thread of electrode, a new measurement method based on CT technology and the image processing technology is put forward. The measurement methods of ordinary thread are contact measurement methods. Non-contact measurements introduced in some literatures are limited to cylinder internal thread. Image processing and detecting of internal taper thread is not still reported. The new method can perform image processing, detect inner false of the work piece and measure geometrical size in one system. Image processing mainly deals with gray-scale transformation, image smoothing & filtering, noise reducing, threshold selecting, binary image, edge detecting and its extracting and so on. Different processing methods are compared. When measuring, based on the segmented contour line of thread, the measurement program to calculate and measure the geometrical parameters of internal taper thread is compiled. Precisions of pitch, thread angle and taper angle reach ±0.03mm、±0.24°and ±0.02°. The reasons of measurement error are analyzed. Theory analysis and experiment results show that this method is feasible and correct. 