ULTRASONIC MEASUREMENTS OF SURFACE-ROUGHNESS

Pulsed ultrasound propagating in water was used at megahertz carrier f requencies (nominally 10-50 MHz) to reflect and scatter from rough sur faces in the same way as light. We have considered noncontact ultrason ic techniques as complementary to optical techniques in several ways: (a) for specific applications such as wet surfaces, (b) for rougher su rfaces with average roughness, R(a) greater-than-or-equal-to 0.1 mum, and (c) for (simultaneous) profilometry by time-of-flight measurements . Stylus and ultrasonic data are compared. An example of application t o the manufacturing environment is for on-line, real-time sensor feedb ack and process control in the cutting or grinding of metals and ceram ics.