Microstructural origin of physical and mechanical properties of polyamide 12 processed by laser sintering

Dupin, Stéphane; Lame, Olivier; Barrès, Claire; Charmeau, Jean‐Yves

doi:10.1016/j.eurpolymj.2012.06.007

Cited by 139 publications

(92 citation statements)

References 18 publications

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“…The capabilities of polyamide 12 to produce these crystals, occurs when hydrogen bonding in the crystal takes place either in parallel or antiparallel fashions (refer Figure 14). However, it is well documented, that the dominant crystalline phase in polyamide 12 is represented by γ-form crystals [49][50][51].…”

Section: Thermal Properties 331 Differential Scanning Calorimetry mentioning

confidence: 99%

The improvement of mechanical and thermal properties of polyamide 12 3D printed parts by fused deposition modelling

Rahim¹,

Abdullah²,

Akil³

et al. 2017

Express Polym. Lett.

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Abstract. This paper addresses the utilisation of fused deposition modelling (FDM) technology using polyamide 12, incorporated with bioceramic fillers (i.e. zirconia and hydroxyapatite) as a candidate for biomedical applications. The entire production process of printed PA12 is described, starting with compounding, filament wire fabrication and finally, FDM printing. The potential to process PA12 using this technique and mechanical, thermal and morphological properties were also examined. Commonly, a reduction of mechanical properties of printed parts would occur in comparison with injection moulded parts despite using the same material. Therefore, the mechanical properties of the samples prepared by injection moulding were also measured and applied as a benchmark to examine the effect of different processing methods. The results indicated that the addition of fillers improved or maintained the strength and stiffness of neat PA12, at the expense of reduced toughness and flexibility. Melting behaviours of PA12 were virtually insensitive to the processing techniques and were dependent on additional fillers and the cooling rate. Incorporation of fillers slightly lowered the melting temperature, however improved the thermal stability. In summary, PA12 composites were found to perform well with FDM technique and enabling the production of medical implants with acceptable mechanical performances for non-load bearing applications.

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Section: Thermal Properties 331 Differential Scanning Calorimetry mentioning

confidence: 99%

The improvement of mechanical and thermal properties of polyamide 12 3D printed parts by fused deposition modelling

Rahim¹,

Abdullah²,

Akil³

et al. 2017

Express Polym. Lett.

View full text Add to dashboard Cite

show abstract

“…A comparison of the processing behavior and the part properties on at least two materials, as in this study, is rarely done [10,13]. This is surprising, as from a commercial point of view, LS materials have been available for a long time from different sources.…”

Section: Introductionmentioning

confidence: 98%

“…• Energy density (A n ) and part orientation in a build envelope [6]; • Incomplete coalescence of polymer melt and resulting process problems [7]; • Influence of powder refreshment and build temperature at a constant energy density (A n ) [8]; • Influence of Energy density (A n ) in combination with powder layer thickness [9]; • Influence of Energy density (A n ) in combination with powder shape [10]; • Variations of temperature in a build envelope and part cylinder [11].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Origin of Polyamide 12 Powder on the Laser Sintering Process and Laser Sintered Parts

et al. 2017

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Different features of polymer powders influence the process of laser sintering (LS) and the properties of LS-parts to a great extent. This study investigates important aspects of the "powder/process/part"-property relationships by comparing two polyamide 12 (PA12) powders commercially available for LS, with pronounced powder characteristic differences (Duraform ® PA and Orgasol ® Invent Smooth). Due to the fact that the primary influence factor on polymer behaviour, the chemical structure of the polymer chain, is identical in this case, the impacts resulting from powder distribution, particle shape, thermal behaviour, and crystalline and molecular structure, can be studied in detail. It was shown that although both systems are PA12, completely different processing conditions must be applied to accomplish high-resolution parts. The reason for this was discovered by the different thermal behaviour based on the powder production and the resulting crystalline structure. Moreover, the parts built from Orgasol ® Invent Smooth unveil mechanical properties with pronounced anisotropy, caused from the high melt viscosity and termination of polymer chains. Further differences are seen in relation to the powder characteristics and other significant correlations could be revealed. For example, the study demonstrated how the particle morphology and shape impact the surface roughness of the parts.

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“…The actual temperature and thus the viscosity are influenced by the absorption behavior of the powder mainly. The resulting material and mechanical properties are dependent on the laser energy input which is dominated by the interaction of the beam with the powder bed [4,5]. While thermal modeling of the process is conducted with simplified absorption models [6,7], a mesoscopic model at the powder scale is still missing.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Laser Beam Absorption in a Polymer Powder Bed

et al. 2018

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Abstract:In order to understand the absorption characteristic, a ray trace model is developed by taking into account the reflection, absorption and refraction. The ray paths are resolved on a sub-powder grid. For validation, the simulation results are compared to analytic solutions of the irradiation of the laser beam onto a plain surface. In addition, the absorptance, reflectance and transmittance of PA12 powder layers measured by an integration sphere setup are compared with the numerical results of our model. It is shown that the effective penetration depth can be lower than the penetration depth in bulk material for polymer powders and, therefore, can increase the energy density at the powder bed surface. The implications for modeling of the selective laser sintering (SLS) process and the processability of fine powder distributions and high powder bed densities are discussed.

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Microstructural origin of physical and mechanical properties of polyamide 12 processed by laser sintering

Cited by 139 publications

References 18 publications

The improvement of mechanical and thermal properties of polyamide 12 3D printed parts by fused deposition modelling

The improvement of mechanical and thermal properties of polyamide 12 3D printed parts by fused deposition modelling

Influence of the Origin of Polyamide 12 Powder on the Laser Sintering Process and Laser Sintered Parts

Modeling of Laser Beam Absorption in a Polymer Powder Bed

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