Development of a test system to make circularity measurements of rubber metal bushes after stress relief

Rubber metal bushings, which are one of the important parts of the suspension system, are expressed as comfort and safety structures that are specially designed to minimize the vibrations and noises that vehicles are exposed to while driving. It is aimed to detect the errors that may occur in the parts earlier by obtaining tight fit conditions and to minimize these errors that may occur in the process of breaking the circularity of the rubber metal parts after the production, placing them with tight fit. After the production of rubber metal parts, the circularity checks are carried out manually so that the errors that may occur in the part can be overlooked. On the other hand, the effect of the diametering process on the rubber-metal connection strength and thus on the mechanical properties of the bush is observed. For this reason, automatic control of circularity measurement after stress relief of rubber metal bushings prevents operator error and provides more accurate and stable measurements. At the first stage, the tolerance values of the bushings in the inventory were determined and the design was provided modularly according to the bushing diversity. Secondly, the preliminary design of the system, material selections, laser sensor to be used, servo motor and motor driver, Raspberry pi-4, industrial type camera and PLC and HMI as controller were determined. With deep learning and image processing algorithms, laser circularity measurements are verified with reference to the circularity of the bush, and spots where the circularity is corrupted or deformed are detected, and the faulty area is transferred to the HMI screen. Laser sensors are equipped in such a way that the height adjustment can be made without error, according to the bushing inventory. Thirdly, the system was assembled and pre-series trials were carried out. With this study, it was ensured that the circularity errors in rubber metal bushings were controlled and that the problems to be encountered after the production were eliminated and a quality production was ensured, and accurate results were obtained by providing a more precise solution by taking the margin of error from the operator. In the current system, circularity measurements in rubber bushings can be measured mechanically. With this study, measurements can be performed with 90% more precision thanks to laser sensor, image processing and deep learning.. Laser measurement method has a wide usage in industrial. However, in practice, laser and deep learning measurement of bushings, which are suspension system components, has not been encountered. With the successful completion of the study, the potential to initiate new studies has been provided so that it can be extended to all stages of production.