Abstract

Although numerous references present the beneficial effects on surface integrity of ultrasonic vibration-assisted ball burnishing (UVABB), nothing has been reported about the dynamic behavior of the UVABB tool, workpiece, and machine triad during the process. In this paper, a dynamic monitorization through a set of 5 accelerometers is tested to analyze the interactions between the tool–workpiece–machine mechanical assembly. A UVABB tool attached to a milling machine and equipped with a piezoelectric stack that is able to assist the process with a 40-kHz vibration is tested on a milled C45 steel surface. First, the natural frequencies of the mechanical system are obtained through hammer impact tests. Then, the vibratory signals transmitted during the execution of the process are monitored and compared to those: two feed velocities and two burnishing preloads, all with and without vibration-assistance. Results show that the proposed accelerometer set is valid to assess the behavior of a UVABB process. The system’s natural frequencies are not varied by vibration-assistance and are not excited when the piezoelectric is functioning. It is confirmed that UVABB is safe for the machine and the tool, and there is no unexpected excited frequencies due to the piezoelectric excitation.

Highlights

  • The high standards that today’s industry demands from workpieces has had no precedents in history due to the high competitiveness present in key sectors foreconomical development

  • It is expressed like this to differentiate it to the actual burnishing force, which can vary during the non-vibration-assisted ball burnishing (NVABB) and ultrasonic vibration-assisted ball burnishing (UVABB) process due to different sources

  • The presented results take us to the conclusion that during the ball-burnishing process performed with an UVABB tool, whether transmitting vibrations or not, the natural frequencies of that tool are excited

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Summary

Introduction

The high standards that today’s industry demands from workpieces has had no precedents in history due to the high competitiveness present in key sectors foreconomical development. Babitski et al [18] observed that systems that could work under different amplitude regimes showed unstable behaviour, and that caused a fall of almost 50% in the final surface roughness obtained This kind of linear vibratory system, ideal for transmitting a high-frequency 1D oscillating movement, is based on a slender sonotrode on whose tip the burnishing ball or the machining insert is installed. The ultrasonic-vibration-assisted ball-burnishing (UVABB) process has been extensively reported by Jerez-Mesa et al (2018) [20] This tool works so that vibrations are introduced through a sonotrode at whose tip the burnishing ball is installed, and whose length changes as an effect of thickness variation of a piezoelectric stack subjected to a difference of potential [21]. The authors have not found previous bibliographical references dealing with this kind of monitoring and modal study of a process where so many excitation sources are present

Experimental Setup
Monitoring of the UVABB Force
Monitoring of Vibrations during UVABB
Impact Tests
Vibration Monitoring
Monitoring of the Burnishing Force
Findings
Conclusions
Full Text
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