Abstract: A thickness monitoring system for measuring the thickness of layer disposed on both sides of a two sided strip includes a thickness measuring device, a first set of guide rollers mounted to guide the strip past the thickness measuring device along a first path, a set of guide pulleys mounted to invert the strip and to offset the strip laterally with respect to the first path, and a second set of guide rollers which guide the inverted strip past the thickness measuring device along the second path. The thickness measuring device is mounted for movement along a third path which is transverse to the first and second paths to allow the thickness measuring device to monitor either side of the strip by positioning the measuring device in alignment with the respective one of the first and second paths.

Abstract: An X-ray thickness monitor is mounted on a moveable carriage which also supports a duty cycle sensor and a shoulder find sensor. The duty cycle sensor is aligned to scan the same portion of a terminal strip as that which passes under the X-ray beam. The duty cycle sensor is used to measure the ratio between the widths of individual terminals in the terminal strip and the period between adjacent terminals. This duty cycle is then used as a correction factor to correct the measured thickness value in order to compensate for gaps between adjacent terminals. The shoulder find sensor monitors the duty cycle at a shoulder on the terminal and moves the carriage as necessary to maintain the shoulder find sensor in position over the shoulder, thereby maintaining the X-ray beam and the duty cycle sensor in position over the crown to be measured. The X-ray monitor is automatically standardized periodically in order to ensure the accuracy of the measurement.