Method for monitoring laser weld quality via plasma light intensity measurements
US6060685A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1997 |
| Grant date | May 9, 2000 |
| Priority date | — |
| Expiry date | Oct 23, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K26/21
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method for monitoring the quality of a laser process such as a laser welding process includes monitoring the light emitted from the weld plasma above the surface of the workpiece irradiated by the laser beam. The intensity of the light emitted from the plasma is compared to a predetermined value of the light emission as determined under process and workpiece conditions that produce welds of acceptable quality. Variations of the monitored light intensity greater than a preselected value can be valuated as unacceptable welds. Such variations can be caused by changes in the laser beam power, the workpiece speed, laser focusing problems, insufficient shield gas flow, workpiece deformation and weld contamination. The process monitors the light emission for a selected range of wavelengths that correspond to the major emission peaks of the light spectrum. The method enables in-process control of laser processes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.