A Proposed Scan Strategy Used on SLM Inner Structure Part.

Jitai Han,Meiping Wu,Weipeng Duan

doi:10.3390/ma13040937

Abstract

A model with an inner structure was designed to study the relationship between the surface quality of the inner structure and the scan strategy in this study. The test results showed that the precision of the inner structure was highly affected by the scan strategy, and the specimens printed using different strategies showed different performances on the surface quality of the inner structure. The specimen printed using the square-framed scan strategy had a lower flatness value on the positive face of the inner structure compared to that of the other two specimens printed using Z-shape scan strategies, while the specimen printed using the Z-shape scan strategy (along the inner structure) had a relative optimal surface roughness on the side surface of the inner structure in all three specimens. The bending deformation caused by the scan strategies was considered to be the main factor affecting the flatness on the positive surface, while laser energy fluctuation showed a significant impact on side surface roughness. Combined with the experimental data, a new scan strategy was proposed; we found that the specimen printed using this new strategy improved positive surface flatness and side surface roughness.

Highlights

Three-dimensional printing (3DP) has attracted increasing attention all over the world due to its near net-shape formability, which is both time- and cost-saving [1]
The flatness value on the positive inner structure surface printed by the square-framed scan strategy was much lower the positive inner structure surface printed by the square-framed scan strategy was much lower than that printed by the other two scan strategies
The performance of the positive surface roughness printed using different scan strategies was similar according to our experimental data

Summary

Introduction

Three-dimensional printing (3DP) has attracted increasing attention all over the world due to its near net-shape formability, which is both time- and cost-saving [1]. There are about 100 factors affecting the properties of the printed parts, but only about 20 of them are considered to be controllable, including layer thickness, hatch spacing, scan speed, scan strategy, laser power, and built orientation [3]. Scan strategy was the only variable parameter due to its commonality and high impact on the properties of printed parts. Cheng et al [4] found that different scan patterns had a great impact on residual stress, and a 45◦ -line scan case led to less deformation in all their results. Lu et al [5] studied different island scan strategies They found that the sample printed using a 2 mm × 2 mm island scan strategy had the lowest residual stress, while the samples printed using 5 mm

Methods

Results

Conclusion