Trend Inspection Station for Printed Circuit Board Solder Joints, Ultrasonic Subsystem.

Abstract : This is the Final Engineering Report on Phase 2.2 work on the ultrasonic subsystem for the trend inspection station for printed circuit board solder joints. The report discusses activities during this contract period in six major areas. Probe assemblies have been refined by redesigning both receiver and transmitter to permit closer spacing of these probes for inspection of small joints. In addition, transmitter design has resulted in a new style probe. Based in part on the characteristics of ultrasonic spectra of the solder joint types of interest, and in part on the mental processes used in visual evaluation of joint spectra to make a judgment on joint quality, several algorithms have been investigated for computerizing the decision making process. A simple but effective algorithm has been devised for use with the latest probe set in inspecting good lap solder joints and those with heel cracks. A probe manipulator for the pilot model of the ultrasonic subsystem was designed and constructed during this contract period. It was used in some of the later experimentation in this period directed to defining performance capability.