Device and method for measuring laser absorptivity of powder

Abstract

The invention discloses a device and method for measuring laser absorptivity of powder. The measuring device comprises a laser, a light path system, an inert gas protection box, a powder container, aheating system, a temperature measuring system and a computer. The measuring method comprises the following steps of: paving powder with thickness in the powder container, and then placing the powdercontainer in the protection box filled with inert gas. The powder is preheated through the heating system to be maintained at a certain temperature. A laser beam with a certain wavelength output by the laser system is amplified and collimated by the light path system and irradiates the surface of the powder. Powder temperature data at different moments are collected through the temperature measuring system, laser energy absorbed by powder is obtained through analysis of a computer, and the absorptivity of the powder to laser with the wavelength is obtained by solving the ratio of the laser energy to laser irradiation energy. Compared with other measuring methods, the method has the advantages that the absorptivity of the powder to incident laser at different temperatures can be obtained, meanwhile, the influence of powder oxidation on the absorptivity in measurement is avoided, and the method is easy and convenient to build and easy to implement.

Description

technical field [0001] The invention belongs to the technical field of laser additive manufacturing, and relates to a measuring device and a measuring method for laser absorption rate of powder. Background technique [0002] During the interaction between the laser and the material, part of the laser light irradiated on the material is absorbed by the material, and the other part is reflected. After the material absorbs the laser energy, it will heat up, melt, gasify and even generate plasma. Based on these phenomena, the material can be processed to a certain extent. It can be seen that the absorption rate of the material to the laser is an important factor affecting laser processing. [0003] Selective laser melting is a method of laser additive manufacturing, which uses high-energy laser beams to selectively melt powder layer by layer, and manufactures three-dimensional solid parts by layer-by-layer powder spreading, layer-by-layer melting, solidification and accumulation...

AI Technical Summary

Problems solved by technology

[0008] (1) The problem of material oxidation in the measurement is not solved;

[0009] (2) Only for the measurement of the absorptivity of the block structure with a flat surface, the gaps in the powder accumulation and the uneven temperature distribution of the powder caused by the concentration of local powder absorption light intensity are not considered;

[0010] (3) It is impossible to measure the absorption rate of laser light by powders with different temperatures

[0011] The above-mentioned defects So far, the existing measurement devices and methods have not been able to accurately measure the laser absorption rate of powders with different temperatures

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