<p>As one of&nbsp;3D printing&nbsp;methods, the selective laser melting (SLM) is capable of&nbsp;manufacturing&nbsp;products with complex shapes, greatly enhancing the design flexibility.&nbsp;However, SLM&nbsp;printed products usually have&nbsp;certain defects on surfaces, such as micro-cracks, unmelted metal powders&nbsp;and re-solidified pool&nbsp;traces, etc, limiting&nbsp;their&nbsp;applications.&nbsp;Therefore, it’s an urgent need to eliminate these defects through&nbsp;post-treatment&nbsp;in order to ensure the normal&nbsp;functions of SLM printed products.&nbsp;Recently, the femtosecond laser processing&nbsp;is considered as one of the most promising technologies, which has attracted tremendous attention. Compared with&nbsp;continuous wave&nbsp;and long pulse lasers, the femtosecond one&nbsp;possesses&nbsp;advantages of high precision, no pollution and low thermal&nbsp;effect. Furthermore, femtosecond laser treatment is able to provide&nbsp;abundant surface&nbsp;properties, such as super-hydrophobicity, super-hydrophilicity, corrosion resistance, self-cleaning and so forth.&nbsp;In the present work, the femtosecond laser was applied&nbsp;to treat the&nbsp;SLM printed samples made of 316L stainless steel. Specifically, the surface morphology and element&nbsp;composition&nbsp;of 3D printed samples&nbsp;were&nbsp;analyzed&nbsp;by changing three laser parameters (i.e., the laser power, scanning speed and number of scans).&nbsp;It’s shown that the amount of the removed material increases&nbsp;with increasing&nbsp;the number of scans and the laser power. For instance, as the number of scans&nbsp;gradually increases from 1 to 100&nbsp;(the laser power is 5&nbsp;W&nbsp;and the scanning speed is 100&nbsp;mm/s), the ablation depth expands from 98&nbsp;to 552&nbsp;μm. Moreover, as the laser power increases from 5 to 10&nbsp;W (the scanning speed is 100mm/s), the increment&nbsp;of the ablation depth depends on the number of scans (achieving the maximal value with 40 laser scans). Besides,&nbsp;the surface topography also changes with the laser parameters. As the number of scans&nbsp;increases from 1 to 100&nbsp;(the laser power is 5&nbsp;W&nbsp;and the scanning speed is 100&nbsp;mm/s), the morphology of the molten pool gradually changes from the original ones to sparsely&nbsp;and then to densely&nbsp;distributed micro-mountains. Another&nbsp;obvious phenomenon is that the oxygen content on the sample&nbsp;surface&nbsp;increases to some extent after femtosecond laser treatment, which could improve the corrosion resistance of materials.&nbsp;By reasonably&nbsp;controlling laser&nbsp;parameters, surface defects of 3D printed&nbsp;samples can&nbsp;be successfully&nbsp;removed. Meanwhile, femtosecond laser provided&nbsp;the surface with certain micro/nanostructures, which&nbsp;will&nbsp;improve the wettability and cell adhesion properties.&nbsp;Finally,&nbsp;this contribution demonstrated that the femtosecond laser can simultaneously eliminate defects and modify surface for&nbsp;3D printed components, facilitating&nbsp;the combination of 3D printing and femtosecond laser applied to more industry fields.</p>

Simultaneously Eliminate Defects and Modify Surface for 3d Printed Components Using Femtosecond Laser

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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