Innovative high-performance process for dry manufacturing of sheet metal armatures and their integrated on-line cleanliness examination

At present armatures and cores in electromagnetic contactor systems consist of soft-iron, soft-magnetic castings or stampings fixed with rivet joints. To guarantee the reliability of the product, it is necessary to integrate a remanence air gap into the magnet system. Today’s state-of-the-art technologies for integrating the remanence air gap lead to high production costs and tolerance problems. To avoid these problems, an innovative high-performance process was developed using a nonmagnetic foil for realizing the remanence air gap. Because of the high demands on the lifespan of the contactors and the critical function of the foil, special attention has to be paid to bonding. Prior to bonding, surface cleanliness has to be guaranteed. To accomplish this task, a cleanliness examination system is being developed consisting of an image processing system and an analytical measurement method. The image processor detects whether or not residues are present and provides the subsequent modified spectroscopy method with a priori information concerning the character of the residue and its location. Out of the analysis of the identified region an objective index is generated describing the extent of contamination. The analysis results support the decision whether or not the foil may be bonded to the armature’s surface.