A Method of On-line Identifying Deviated State of Incident Laser

Abstract

The invention discloses a method for identifying a deviation state of incident laser in an online manner. The method is used for carbon dioxide laser welding on metal plates which are of sandwich structures. The method includes shooting light-induced plasma cloud images by the aid of a high-speed camera in welding procedures; computing feature parameters of the plasma cloud images; computing process statistic quantities of the feature parameters of the images in set time periods; determining comprehensive indexes by the aid of a principle component analysis process; judging a position deviation degree of the incident laser according to the comprehensive indexes. The method has the advantages that the position deviation state of the incident laser can be accurately and quickly judged in the dioxide laser welding procedures for the metal plates which are of the sandwich structures, devices are simple, interference on the laser welding procedures can be prevented, and the method can be widely applied to the field of carbon dioxide laser welding on metal plates which are of sandwich structures.

Description

technical field [0001] The invention relates to the technical field of carbon dioxide laser welding, in particular to a method for on-line identification of incident laser deviation states during carbon dioxide laser welding of sandwich-structured metal plates. Background technique [0002] As a lightweight structure, sandwich steel plate has the advantages of light specific gravity, good rigidity, and strong impact resistance. It is widely used in the fields of ships, bridges, and buildings. Usually, the panel and the core plate of the sandwich structure are connected by high-power laser welding of the T-shaped joint, that is, the laser is irradiated on the panel, reaches the core plate through the keyhole on the panel and causes the core plate to melt, and finally forms the panel and Welding between core plates. This special welding method requires the incident laser to be aligned with the center line of the core plate, but in the actual production process, factors such a...

AI Technical Summary

Problems solved by technology

This method is not feasible for laser welding of sandwich-structured metal sheets

[0004] 2) The seam tracking method described in the patent "A laser welding seam tracking device and its control method" (application number: 200910012657.9) is based on the light pattern information at the groove or joint, and can only be applied to butt joints or laser welding of lap joints

[0005] 3) The patent "Active Short-wavelength Laser Welding Small Hole Monitoring and Weld Seam Tracking Integrated Device" (application number: 201110382357.7) integrates weld seam tracking and small hole monitoring in the welding process into an imaging system, but the weld seam tracking However, it is still a joint image-based method, which limits its application in sandwich structures

On the one hand, in its disclosed information, it does not involve whether this method can be used to judge the deviation degree of the incident laser; Causes serious interference, and puts forward high requirements on the exposure intensity of the auxiliary light source, as well as the synchronization of the light source and the camera, so the detection system is very complicated and expensive

[0007] It can be seen that there is currently no effective means for online identification of the incident laser deviation state of the high-power laser deep penetration welding of the sandwich structure metal plate, and the qualified joint between the panel and the core plate cannot be guaranteed, which will eventually weaken the mechanical properties of the sandwich structure. even cause serious safety hazards

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