EDDY-CURRENT NONDESTRUCTIVE TESTING METHODS FOR ON-LINE DETECTION OF CABLE MANUFACTURING DEFECTS

THE MAGNETS FOR THE SUPERCONDUCTING SUPER COLLIDER (SSC) WILL REQUIRE APPROXIMATELY 60 MILLION FEET OF CABLE THAT MUST BE MANUFACTURED TO STRICT MECHANICAL AND ELECTRICAL TOLERANCES. DURING THE RESEARCH AND DEVELOPMENT (R&D) PHASE OF THE SSC PROJECT, SEVERAL TYPES OF CABLE DEFECTS THAT CAN COMPROMISE THE PERFORMANCE OF THE MAGNETS HAVE BEEN IDENTIFIED. AT PRESENT, THESE DEFECTS ARE MONITORED AND DETECTED BY A TRAINED OPERATOR WHO MUST OBSERVE THE CABLE DURING MANUFACTURE. ALTHOUGH THIS APPROACH IS ADEQUATE FOR THE RELATIVELY SMALL QUANTITY OF CABLE BEING PRODUCED IN THE R&D PHASE, THIS APPROACH IS NOT FEASIBLE FOR THE PRODUCTION PHASE. EDDY-CURRENT TECHNOLOGY HAS GAINED WIDE ACCEPTANCE AS A TOOL FOR DETECTING SURFACE AND NEAR-SURFACE FLAWS IN METALS. THE OVERALL OBJECTIVE OF THE PHASE I EFFORT IS TO DEMONSTRATE THE FEASIBILITY OF USING EDDY-CURRENT TECHNOLOGY FOR DETECTING SUPERCONDUCTING CABLE MANUFACTURING DEFECTS IN A PRODUCTION ENVIRONMENT. SPECIFICALLY, PROBE CONCEPTS FOR DETECTING BROKEN OR MISSING WIRE, CROSS OVERS, SHARP CORNERS, AND COLD WELDS ARE BEING PROVED. DIGITAL DATA PROCESSING TECHNIQUES FOR ENHANCING SIGNALS AND INCREASING SIGNAL-TO-NOISE RATIOS FROM EACH DEFECT TYPE ARE BEING EVALUATED. PHASE I RESULTS ARE INTENDED TO PROVIDE THE BASIS FOR DEVELOPMENT OF A PROTOTYPE INSPECTION SYSTEM IN PHASE II.