Roughness measurement and characterization of machined surfaces using ultrasonic waves
Abstract
A surface roughness measurement technique suitable for in-process monitoring in production machining processes has been investigated analytically and experimentally. The technique is based on the utilization of focused ultrasonic beams with non-zero incidence angle and measurement of the reflected beam intensities. The characteristics of focused ultrasonic waves are analyzed by using the impulse response method with a sine-modulated Gaussian pulse as source. First, the beam profile in the focal plane of the focused ultrasonic transducer is analyzed both numerically and experimentally. Second, peak amplitude distribution and reflected waveforms from a flat surface with various incidence angles are analytically generated and compared with experimental results. Then, the peak amplitudes of the ultrasonic waves reflected from cusped surfaces that are easily found among machined surfaces are analyzed and compared with experimental data. The test of sensitivity and robustness of the proposed technique is also conducted with various milled surfaces of different materials. The analysis shows good agreement between analytical and experimental results. The excellent correlation between the measurements of a profilometer and of the proposed ultrasonic system demonstrates a good potential for surface roughness measurement by ultrasonic sensing. Finally, the successful reconstruction of a profile from an ultrasonic measurement demonstrated the ability of monitoring surface profiles through the use of a surface characterization technique utilizing Beta function parameters.
Degree
Ph.D.
Advisors
Furgason, Purdue University.
Subject Area
Mechanical engineering|Electrical engineering|Industrial engineering
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