Laser scanning method for fabricating three-dimensional objects

Abstract

The invention provides a laser scanning method for manufacturing a three-dimensional object. The method comprises: a current cross section contour is divided into a plurality of to-be-scanned areas, wherein all boundaries of the current cross section contour are divided, the to-be-scanned areas are in shapes of regular hexagons or partial regular hexagons, and the gaps among the adjacent to-be-scanned areas are larger than or equal to zero; filling scanning is carried out on the insides of the multiple to-be-scanned areas and the scanning lines employed by the adjacent to-be-scanned areas form preset included angles, wherein the preset angles are larger than 0 degree and are less than 180 degrees; and for all adjacent to-be-scanned area gaps, scanning is carried out by using at least one scanning line. According to the invention, compared with the regular-triangle partition scanning, the regular-hexagon partition areas are proper and no shortest scanning filling path exists, and the laser does not need to be turned on or off frequently, so that the scanning efficiency is high. Moreover, compared with the chessboard partition scanning, the scanning lines of the regular-hexagon partition are different, so that the residual stress between the adjacent scanning lines can be released easily. Therefore, with the laser scanning method, the residual stress influence is reduced; the scanning efficiency is not affected; and the workpiece molding quality is improved.

Description

technical field [0001] The invention belongs to the technical field of rapid prototyping, and in particular relates to a laser scanning method for manufacturing three-dimensional objects. Background technique [0002] Rapid Prototyping (RP) is an advanced manufacturing technology with distinctive features such as digital manufacturing, high flexibility and adaptability, direct CAD model drive, fast speed, and rich and diverse material types. Since the late 1980s, So far, it has become a pillar technology in modern advanced manufacturing technology. Taking the selective laser melting technology as an example, the specific process mainly includes layered slicing, powder feeding, and laser scanning steps. In the laser scanning step, the planning of the scanning path has a great influence on the heat distribution, residual stress distribution, and workpiece in the forming process. Accuracy as well as scan rate etc. play a crucial role. [0003] In the prior art, laser scanning...

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Problems solved by technology

[0003] In the existing technology, laser scanning with checkerboard partitions is mostly used. However, the residual stress distribution of the checkerboard partition scanning method is discrete, and the scanning strategy needs to be changed frequently, and the span is large, which affects the scanning efficiency.

[0004] In the prior art, laser scanning is also carried out by using equilateral triangular partitions. Although this scanning method can solve the technical problem of discrete residual stress distribution, due to the positions of the three corners of the equilateral triangle, the scanning line is relatively short, which requires frequent switching of the laser. , which not only affects the service life of the laser, but also greatly reduces the scan rate

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