Scanning laser ultrasound and wavenumber spectroscopy for in process inspection of additively manufactured parts
We present a new in process laser ultrasound inspection technique for additive manufacturing. Ultrasonic energy was introduced to the part by attaching an ultrasonic transducer to the printer build plate and driving it with a single tone, harmonic excitation. The full field response of the part was measured using a scanning laser Doppler vibrometer after each printer layer. For each scan, we analyzed both the local amplitudes and wavenumbers of the response in order to identify defects. For this study, we focused on the detection of delamination between layers in a fused deposition modeling process. Foreign object damage, localized heating damage, and the resulting delamination between layers were detected in using the technique as indicated by increased amplitude and wavenumber responses within the damaged area.
SPIE Smart Structures and Materials Nondestructive Evaluation and Health Monitoring