End-Face Position Measurement of Work Piece During Press Work Using Surface Wave Reflection

In press operations, accurate measurement of the edge position of the workpiece between the bolster and die leads to improved machining accuracy and productivity. In general, laser ranging is highly accurate, but ultrasonic ranging is effective considering the cost and ease of installation of a measurement system. In this study, we investigated high-precision ranging of workpiece edge positions based on surface wave reflections and their super-resolution. Surface waves are dispersive, which degrades the reflected waveform and affects the ranging accuracy. Therefore, we evaluated the effectiveness of suppressing the waveform degradation using dispersion-compensating ultrasonic transmission. This dispersion-compensating transmission was also found to be highly effective in super-resolving the echo pulse.