Currently in the traditional industrial production, sand defect detection is mainly rely on workers eyes visual, measuring the size with the defect rulers.

This paper analyzes the system of the online measuring of sand defect Image acquisition, determine the camera and light in the sand defects detection equipment and complete set of hardware.

By setting chills on the defect locations to isolate the molten iron in those areas from contact with the resin sand, the defects were successfully avoided.