System for controlled vibration stress relief of metal parts with residual internal stresses using wavelet filtering

This article presents the implementation of a controlled vibration stress relief system for the dimensional stabilization of metal parts. The goal is to eliminate as much as possible of the unsteady internal stress, without affecting the steady stress condition. The time and frequency analysis is more suitable for non-stationary signals, since separate time or frequency specifications are not enough to provide comprehensive information about non-stationary signals. The wavelet transform based on LabVIEW programming was used to remove noise from picked up vibration signals and then to extract features from them. The equipment for the stress relief through vibrations is a complex system including a process computer, a frequency converter, an eccentric vibrator, a flexible shaft, an induction motor and an acceleration transducer. The system reduces the level of residual internal stresses in a certain metal part, following its own stress relief algorithm implemented in LabVIEW environment, achieve automatic reports, store the evolution in a database and sending the reports to default email addresses. There are presented results of the system presented after vibration stress relief of a work piece. © 2019, Politechnica University of Bucharest. All rights reserved.