Noncontacting displacement transducers locate and quantify defects on magnets

During their manufacture, ferrite magnets are subject to thermal and mechanical loads which sometimes cause surface chipping or breakage.

During their manufacture, ferrite magnets are subject to thermal and mechanical loads which sometimes cause surface chipping or breakage. In order to single out defective magnets, a thorough visual examination is generally carried out in connection with the packaging process. In the case presented, automation of the packaging process made it necessary to search for a technique for automatic defect detection and quantification which would match the necessary criteria for speed and reliability. This article introduces a technique for automatic examination of dish-shaped permanent magnets using noncontacting displacement transducers. Advantages of the system include easy construction and uncomplicated signal processing.