Method for cooperatively detecting particles in laser welding plume through multiple laser beams

Abstract

The invention discloses a method for cooperatively detecting particles in laser welding plumes through multiple laser beams, and belongs to the technical field of laser welding. A measurement system is composed of a plurality of detection lasers with different wavelengths, a focusing system, a data acquisition card and a signal processing system. The plurality of detection lasers with different wavelengths are focused at the same position in the plume through the respective focusing systems, meanwhile, the detection lasers are scattered by the particles in the plume, and part of the scattered light enters the respective detection lasers again to cause a self-mixing effect and enable the output voltage signals of the detection lasers to change; and the information, such as the diameter and the density of the particles, etc., can be obtained by processing the output voltage signal. According to the present invention, the particles at the same position in the plume can be cooperatively detected through the plurality of detection lasers with different wavelengths, so that the measurement range of the diameter of the particles at the measurement position is wider (10 nm-50 micrometers), and the diameter of the particles in the plume and the corresponding density condition can be more accurately measured in situ in a large range.

Description

technical field [0001] The invention relates to a method for cooperatively detecting particles in a plume with multiple laser beams, belonging to the field of laser material processing. Background technique [0002] The rapid development of 1μm level lasers (fiber laser, Nd:YAG laser, disk laser and semiconductor laser) is an important progress in the field of laser science. This type of laser can be transmitted through optical fibers, and has the advantages of high absorption rate, high power, high processing flexibility, and low operating cost when used in metal material processing. Feather glow is an inherent physical phenomenon during laser welding with a wavelength of 1 μm, which has a significant negative impact on the welding process. The essence of the influence of the plume on laser welding is that there are a large number of particles in the plume, and the particles in the plume attenuate the laser energy and change the propagation direction of the beam through ab...

AI Technical Summary

Problems solved by technology

However, the diameter of the particles in the plume is between 10nm and 50μm, and the particles whose diameter is smaller than half the wavelength of the detection laser cannot be detected; while the particles whose diameter is much larger than the wavelength of the detection laser have too many interference fringes, which is difficult to count.

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