A robust in-process monitoring of pulsed laser spot welding using a point infrared sensor

• Published in: Proceedings of the Institution of Mechanical Engineers. Part B, Journal of engineering manufacture Vol. 212; no. 3; pp. 241 - 250
• Main Authors: Lim, D-C, Cho, Y-B, Gweon, D-G
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.01.1998; Mechanical Engineering Publications; SAGE PUBLICATIONS, INC
• Subjects: Analysing. Testing. Standards; Applied sciences; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Industrial metrology. Testing; Infrared detectors; Infrared imaging; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Materials science; Materials testing; Mechanical engineering. Machine design; Metals. Metallurgy; Monitoring; Non-destructive testing: methods and equipments; Nondestructive examination; Nondestructive testing; Physics; Pulsed laser applications; Robustness (control systems); Spot welding; Testing for defects; Thermal analysis, differential thermal analysis (DTA), differential thermogravimetric analysis; Thermal instruments, apparatus and techniques; Thermometry; Nd:YAG laser; non-destructive monitoring; pulsed laser spot welding; infrared sensor; in-process monitoring; Infrared thermography; On line; Surface temperature; Experimental study; Modeling; Laser welding; Pulsed laser; Sheet metal; Quality control; Testing equipment; Spot welding; Measurement method; Non destructive test; Monitoring; Heat transfer
• ISSN: 0954-4054; 2041-2975
• DOI: 10.1243/0954405981515653

Abstract Many manufactured goods employ pulsed laser spot welding in joining and it is important to monitor the weld quality. The weld quality is highly related to the thermal history of the weld and there have been many trials to monitor the quality using an infrared (IR) sensor. Though the emitted thermal radiation is a function of the emissivity and the surface temperature, the measuring condition has an important influence on the detectable radiation. To increase the reliability of monitoring, it is useful to find the robust feature that is immune to the change of measuring condition. This paper suggests an in-process monitoring method using a point IR sensor for the pulsed laser spot welding of thin metal sheet. The suggested monitoring method is robust to the change of the measuring condition and it can detect the variation of the absorbed energy as well as any serious defect in the weldment.