scholarly journals Selective laser sintering of copper filled polyamide 12: Characterization of powder properties and process behavior

2018 ◽  
Vol 40 (5) ◽  
pp. 1801-1809 ◽  
Author(s):  
Lydia Lanzl ◽  
Katrin Wudy ◽  
Sandra Greiner ◽  
Dietmar Drummer
2021 ◽  
Vol 33 (3) ◽  
pp. 658-664
Author(s):  
H. Chiririwa

Selective laser sintering (SLS) had been recognized as production expertise (additive manufacturing). The complication restricting the use of SLS in additive manufacturing in an extensive range of industrial scope is the limited selection of usable polymers as it is only limited to polyamide 12. Other polymeric materials such as polypropylene and polyethylene are needed to establish pristine market avenues in industry. In selective laser sintering, the powder is reused in consecutive cycles of the route for the reason that it is sustainable and cost effective. Characterization procedures, including the many available techniques has been proposed to determine changes in chemical microstructures, morphology along with flowability. Subtle disimilarities linking virgin and used powder have been identified through characterization.


2018 ◽  
Vol 24 (5) ◽  
pp. 813-820 ◽  
Author(s):  
Junjie Wu ◽  
Xiang Xu ◽  
Zhihao Zhao ◽  
Minjie Wang ◽  
Jie Zhang

Purpose The purpose of this paper is to investigate the effect of selective laser sintering (SLS) method on morphology and performance of polyamide 12. Design/methodology/approach Crystallization behavior is critical to the properties of semi-crystalline polymers. The crystallization condition of SLS process is much different from others. The morphology of polyamide 12 produced by SLS technology was investigated using scanning electron microscopy, polarized light microscopy, differential scanning calorimetry, X-ray diffraction and wide-angle X-ray diffraction. Findings Too low fill laser power brought about bad fusion of powders, while too high energy input resulted in bad performance due to chain scission of macromolecules. There were three types of crystal in the raw powder material, denoted as overgrowth crystal, ring-banded spherulite and normal spherulite. Originality/value In this work, SLS samples with different sintering parameters, as well as compression molding sample for the purpose of comparison, were made to study the morphology and crystal structure of sintered PA12 in detail.


Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5285
Author(s):  
Babette Goetzendorfer ◽  
Thomas Mohr ◽  
Ralf Hellmann

We introduced a new approach in selective laser sintering for hybrid multicomponent systems by fabricating the sintered polyamide 12 (PA12) part directly onto a similar (PA12) or dissimilar (polyamide 6 (PA6) and tool steel 1.2709) joining partner. Thus, the need for adhesive substances or joining pressure was completely circumvented, leading to the possibility of pure hybrid lightweight bi-polymer or metal–polymer systems. By taking advantage of the heating capabilities of the sinter laser regarding the substrate surface, different exposure strategies circumvented the lack of overlapping melting temperatures of dissimilar polymers. Therefore, even sintering on non-PA12 polymers was made possible. Finally, the transfer on metallic substrates—made up by selective laser melting (SLM)—was successfully performed, closing the gap between two powder-based additive processes, selective laser sintering (SLS) and SLM.


2019 ◽  
Vol 80 ◽  
pp. 106094 ◽  
Author(s):  
Sean Petzold ◽  
James Klett ◽  
Andrew Schauer ◽  
Tim A. Osswald

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 609 ◽  
Author(s):  
Nicolas Hesse ◽  
Maximilian Dechet ◽  
Juan Bonilla ◽  
Christian Lübbert ◽  
Stephan Roth ◽  
...  

Powder flowability is key to achieving high process stability and part quality by application of smooth and dense layers in selective laser sintering (SLS). This study sheds light on the rarely investigated effect of tribo-electric charge build-up during powder delivery in the SLS process. This is achieved by a novel approach to quantify electrostatic potentials during doctor blading. The presented model setup is used in combination with charge spectrometry and impedance spectroscopy to investigate the alterations in tribo-electric charging behavior for the most commonly used laser sintering material polyamide 12 in its virgin and aged, c.f. reused, states. We show that the electrostatic charge build-up is significantly enhanced for aged polymer powder material, likely contributing to altered performance in SLS processing.


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