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

Abstract

Commercially available materials for selective laser sintering (SLS) include mainly semicrystalline polymers and only a few composites like polyamide 12 filled with glass beads or aluminum. Powder composites can be used for setting tailored properties. Exemplarily, mechanical properties as well as thermal or electrical conductivity can be improved. Thermally conductive SLS parts filled with copper particles have not been under investigation before. This study contains the characterization of polyamide 12 filled with copper acting as a metal filler with a high thermal conductivity. Two composites differing in the filler shapes are investigated concerning powder properties and the resulting processability. The thermal conductivity in dependence on the filler content and anisotropy is of major interest. Isotropic, spherically shaped copper fillers are compared with strongly anisotropic flakes leading to the result that a much lower content of anisotropic filler is needed to reach an increased thermal conductivity. However, the powder flowability and processability is also highly influenced by the filler shape and content. Fillers with a similar shape like the matrix powder lead to a better flowability allowing higher filler contents. POLYM. COMPOS., 40:1801–1809, 2019. © 2018 The Authors Polymer Composites published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers

Recent Progress on Polymer Materials for Additive Manufacturing

“…Glass bead/PA12 [161a] Cu/PA12 [200] CF/PA12 [201] GF/PA12 [202] Carbon black/PA12 [203] OMMT/PP [140] GNP a) /PEEK [190b] • MWCNT/PA12 [189,191,204] MWCNT/TPU [190a,204a] SWCNT b) /TPU [205] Carbon black/PA12 [206] Graphene/TPU [192] OMMT/PP [140] GNP/PEEK [190b] GNP/PA12 [207] • Low cost • Moderate filler dispersion on powder particle surfaces • Good interfacial interaction possible • Solvent intensive Melt blending and mechanical grinding CNF/PA12 [194] OMMT/PP [140] BaTiO 3 /PA11 [162] • Good filler dispersion in powder particles • Good interfacial interaction possible • Irregular particle shape • Poor powder flowability • Particle rounding or other post-processing treatment required…”

“…Metal fillers such as copper and aluminum are also used as reinforcements to improve the modulus of printed parts as well as their thermal and electrical conductivity. [ 200 ] For instance, Alumide from EOS is a commercial aluminum/PA12 composite powder that is used for the manufacture of stiff parts with metallic luster for automotive applications.…”

The combination of Al2O3 and BN for enhancing the thermal conductivity of PA12 composites prepared by selective laser sintering

“…6,7 Selective laser sintering (SLS) is currently one of the most promising 3D printing technologies, based on the basic principle of high-temperature sintering of powder materials under laser irradiation. 8,9 When compared with traditional manufacturing methods, SLS technology demonstrates greater advantages in the fabrication of materials with complex shapes and high precision. 10 With excellent mechanical properties and good thermal stability establishing it as an effective component for the 3D printing of raw materials, 11,12 polyamide 12 (PA12) is one of the most widely utilised engineering plastics, applied to electronics and the automotive industry.…”

Flame-Retardant Polyamide Powder for Laser Sintering: Powder Characterization, Processing Behavior and Component Properties

“…The use of fillers or additives leads to a change in the process behavior of the composite materials. For example, the thermal behavior of filled and un-filled materials differs [ 28 ]. Therefore, a temperature search was carried out based on the recommended building temperature of the matrix material.…”