Characterisation of a laser droplet formation process by acoustic emission

• Published in: Ultrasonics Vol. 42; no. 1; pp. 99 - 103
• Main Authors: Govekar, E., Klemenčič, J., Kokalj, T., Jahrsdörfer, B., Mužič, P., Grabec, I.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2004; Elsevier Science
• Subjects: Acoustic emission; Acoustics; Droplet detachment; Droplet formation; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Laser beam; Physics; Ultrasonics, quantum acoustics, and physical effects of sound; Droplet formation; Acoustic emission; Laser beam; Droplet detachment; Acoustic emission testing; Heat source; Liquid metal; Metal coating; On line; Acoustic measurement; Reliability; Droplet; Non destructive test; Operating conditions
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/j.ultras.2004.01.026

The aim of this article is to describe an application of acoustic emission to characterise a process of laser droplet formation from a metal wire. Laser droplet formation is a crucial process in new laser droplet welding technology, where parts are joined by means of the heat content of a liquid metal droplet deposited onto the parts to be joined. A laser beam is used for heating and melting the wire tip, and for detaching the molten pendant droplet. Depending on the process parameters, three different outcomes of the process can be observed: (1) no droplet formed; (2) a droplet formed but not detached; (3) a droplet formed and detached from the wire. It is shown that AE can be used to monitor the process and to indicate the different process outcomes.