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Communication Dans Un Congrès Année : 2023

Thermal conductivity of glass/talc filled Polyamide 12 as function of tapping level

J. Lopez-Cuesta
Yannick Le Maoult
Marcos Batistella
Rémi Gilblas
Fabrice Schmidt

Résumé

Selective laser sintering is a layer-by-layer process that allows complex shapes to be processed but requires specific properties for the powder used to build the final object. The advantages of free crucible processing and freedom of design makes this process interesting for several applications. Despite the large number of SLS printer available in the market, a deep understanding of the physical phenomena of this process is still lacking, due to the number of parameters involved, directly influencing the final part’s properties through the microstructure. In this work, glass beads or talc were added to Polyamide 12 (PA 12) matrix in order to evaluate these filler’s influence on powder bed. We started with PA 12 and glass beads (PA90/GB10 in wt%) untill 70/30 wt%, with a 5 wt% increment. As SLS operates with CO2 laser working at 10.6μm to melt powders, it is fundamental to investigate how heat will be conducted through the different sintered layer. Various parameters can influence thermal conductivity of filled Polyamide 12 powder bed such as particle shape, aspect ratio, chemical composition, presence of impurities and also the packing of the particles from powder bed. Hence, porosity is such an important parameter as air inside is highly insulating the material and reduces its thermal conductivity by convection between pores. This convection is also governed by the pores size. (Rayleigh criterion) Several experiments were carried out in order to evaluate the thermal conductivity as a function of porosity which highly depends on how particles are settled, thus how the powder bed is tapped. These results were obtained using a hot wire conductivity meter from Neotim which can give thermal conductivity through a powder bed. To determine samples porosity, we used a powder tester which returned powder densities for different tapping levels. As we are working with filled polyamide 12 matrix, a huge drop of flowability has to be considered upon addition of filler which can cause issues during the process. Changes of processing parameters could be required due to significant modifications of the thermal behavior resulting from the presence of fillers.

Domaines

Matériaux
Fichier non déposé

Dates et versions

hal-04172475 , version 1 (27-07-2023)

Identifiants

  • HAL Id : hal-04172475 , version 1

Citer

Dylan Seigler, J. Lopez-Cuesta, Yannick Le Maoult, Marcos Batistella, Arnaud Regazzi, et al.. Thermal conductivity of glass/talc filled Polyamide 12 as function of tapping level. PPS 38 - The 38th International Conference of the Polymer Processing Society, May 2023, St Gallen, Switzerland. ⟨hal-04172475⟩
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