Dimensional quality control of screw using machine vision technique

In most industries, screws are used to mount and connect parts to each other, as well as to adjust industrial devices or to transfer motion. For this reason, it is important to follow with the standards developed in screws to prevent accidents. This study describes the application of machine vision scanner to measure the external thread hex head bolts geometric dimensions. The parameters, including thickness of head, thread length, thread diameter, the screw pitch, width across corners, and width across flats were measured by an industrial camera and with the help of image processing software. According to the accuracy of calibration, the measurement has been done with an average error percentage of ۰.۸۲. In the next step, the sizes obtained from the machine vision scanner have also been compared with the values provided in the DIN standard. The results show that measurement with the help of machine vision can be used as a powerful tool for automation during the screw manufacturing stage in order to increase the production quality