Invited Speaker
Dr. Andrei POPESCU
Center for Advanced Laser Technologies, National Institute for Lasers, Plasma and Radiation Physics, Bucharest, RomaniaSpeech Title: Metal’s Laser Welding Defects Analysis
Abstract: As a Laboratory dedicated to technological transfer in the field of laser welding and additive manufacturing, a significant interest is devoted to the quality control of produced parts. During the development of technologies, we usually monitor in situ the experiments via high-speed imaging and thermography. One of our purposes is to identify as fast as possible the defects, so that to be able to separate the conform parts from the deviant ones non-destructively. If there are no possible associations between features of the plasma plume during laser processing and the defects that appear during processing, X-ray imaging (radiography/tomography) is the selection of choice for non-destructive defects assessment.
The presentation will focus on examples of technologies that are developed for various companies in Romania, that take into consideration the non-destructive defects assessment and possible correlations between processing features and defects outcome in case of processing of metal matrix composites and metal alloys.
Correlations between metallographic analyses and area/intensity of the hot vapor in various locations of the samples help to automize the in-situ quality control of samples. Based on the characterization of the hot vapor, it has been found that the increase of the vapor area that exceeded a threshold value was a sign of pores formation within the weld seam.
In parallel, X-ray tomography allows for fast defects identification, thus reducing the necessity for metallographic preparation of samples and manual optical microscopical observations, thus reducing significantly the time for quality control in case of companies adopting our technologies.
Keywords: laser welding, high-speed imaging, porosity control, hot vapor, process optimization, X-ray imaging characterization
Biography: Dr. Eng. Habil. Andrei Popescu worked in the last 10 years with high power lasers and CNC machines to develop new methods and technologies in the fields of additive manufacturing and laser welding for the industrial sector. Besides his academic work which comprises 82 papers in ISI journals, a Hirsch factor of 25 and 6 book chapters, his resume includes 5 national approved patents and 9 technologies with maturity levels TRL>6 transferred to national companies. His current interests lie in additive manufacturing of metallic large scale parts, metal matrix composite materials, welding of dissimilar materials, laser hardening and laser surface micro structuring.