内螺纹自动检测机台设计

Design of Internal Thread Automatic Inspection Machine Station

由于内螺纹特殊的结构与空间位置的限制,传统的螺纹检测方法效率低且容易造成漏检,因此开发出光学螺纹塞规(OTPG),对内螺纹工件进行非接触式的自动化检测。OTPG以内视镜及电荷藕合元件(CCD)组成取像光学模组,通过触发器与两组马达控制单元,逐步拼贴连续拍摄到的部分螺纹影像,以重建出360°内螺纹壁的二维全周影像图,然后运用傅立叶转换法将影像还原,并配合统计控制图的二值化法来突显依附在内螺纹上的瑕疵,如螺纹坡上凸起状的刮痕、螺峰或螺谷上凹陷状的崩塌或裂痕等。实验结果显示,自动化检测机台的检测率可达97. 72%,克服了接触式螺纹塞规仅能检测出凸起状瑕疵的限制,确保了内螺纹的品质。

Due to the special structure and spatial position of internal thread,traditional thread detection methods are inefficient and easily to cause undetected,so the optical thread plug gauge (OTPG)is developed,it enables non -contact automated inspection of internally threaded workpieces.OTPG consists of an endoscope and a charge coupled device (CCD),through trigger and two sets of motor control unit,realizing step-by-step collage of successively captured partial thread images,to reconstruct a 2D full-circle image of a 360-degree internally threaded wall.Then,using the Fourier transform method to restore the image,in conjunction with statistical control chart binarization method to highlight the attachment to the internal thread,such as convex scratches on the thread slope,collapsed or cracked depressions on spiral or spiral valleys.Experiment results show,that detecting rate of automatic inspection machine reaches 97.72%,overcoming the limitation of contact-type thread plug gauges can only detect raised ridges,it can further ensure the quality of internal thread.