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An improved medial axis path generation algorithm for selective laser melting

Li Zhang (School of Mechanical Science and Technology, Huazhong University of Science and Technology, Wuhan, China)
Linshan Ding (School of Mechanical Science and Technology, Huazhong University of Science and Technology, Wuhan, China)
Saif Ullah (Department of Industrial Engineering, University of Engineering and Technology, Lahore, Pakistan)
Tao Hu (School of Mechanical Science and Technology, Huazhong University of Science and Technology, Wuhan, China)
Yangyang Xu (School of Mechanical Science and Technology, Huazhong University of Science and Technology, Wuhan, China)
Li Chen (School of Mechanical Science and Technology, Huazhong University of Science and Technology, Wuhan, China)
Muhammad Hanif (School of Mechanical Science and Technology, Huazhong University of Science and Technology, Wuhan, China)

Rapid Prototyping Journal

ISSN: 1355-2546

Article publication date: 19 September 2020

Issue publication date: 28 November 2020

242

Abstract

Purpose

The principle of the medial axis calculation is complicated and difficult to implement. Moreover, the accuracy is not high. Then, as the generated path has an endpoint at the boundary of the polygon, burrs may appear on the surface of the molded piece. This paper aims to improve the warpage deformation of SLM molded parts and the surface quality of molded parts, an improved mid-axis path generation algorithm is proposed.

Design/methodology/approach

First, the center point is calculated by the seed point growth method based on the distance transform, and the obtained medial axis has high precision and is suitable for simple polygons and complex polygons. Then, based on the extracted medial axis, a preliminary path is generated, the path is trimmed with MATLAB to remove the redundant path. Finally, a scan along the contour of the polygon is performed to improve the surface quality of the molded part.

Findings

The algorithm reduces the internal stress generated during the molding process by continuously changing the scanning direction of the path along the boundary curve of the scanning area, thereby reducing the amount of warpage of the molded part. The result of extraction has a higher precision and wider scope of application than other methods to extract central axis, such as the Voronoi diagram-based method. The path is trimmed to remove redundant paths and the polygon boundaries are scanned to further improve the surface quality of the molded part. The results show that warpage deformation of the proposed algorithm is significantly smaller than the other two methods, thus the forming precision is higher.

Originality/value

An improved medial axis path generation algorithm is proposed in this paper. The proposed method is applied to improve warpage deformation occurring in the SLM process. Seed point growth of distance transformation is used to extracted central axis. The result of extraction has a higher precision and wider scope of application than other methods to extract central axis, such as the Voronoi diagram-based method.

Keywords

Acknowledgements

This work was financially supported by:

National Key R&D Program of China (Number: 2019YFB 1311100).

The Open Topics of State Key Lab of Digital Manufacturing Equipment and Technology of Huazhong University of Science and Technology (Number: DMETKF2020003).

Citation

Zhang, L., Ding, L., Ullah, S., Hu, T., Xu, Y., Chen, L. and Hanif, M. (2020), "An improved medial axis path generation algorithm for selective laser melting", Rapid Prototyping Journal, Vol. 26 No. 10, pp. 1751-1759. https://doi.org/10.1108/RPJ-04-2019-0109

Publisher

:

Emerald Publishing Limited

Copyright © 2020, Emerald Publishing Limited

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