TY - JOUR

T1 - Selecting the suitable thermoplastic elastomer as the main component in the feedstock for metal material extrusion of aluminium

AU - Momeni, Vahid

AU - Shahroodi, Zahra

AU - Hufnagl, Margarete

AU - Gonzalez-Gutierrez, Joamin

AU - Duretek, Ivica

AU - Schuschnigg, Stephan

AU - Kukla, Christian

AU - Holzer, Clemens

N1 - Publisher Copyright: © 2024 The Authors

PY - 2024/8/8

Y1 - 2024/8/8

N2 - Metal material extrusion (MMEX) involves the systematic deposition of material layer by layer, followed by debinding and sintering to produce fully dense metallic parts. The feedstocks, initially comprising metal powder and a binder system, are pivotal in determining processability and final properties. This study utilized polylactic acid (PLA) as the backbone and a thermoplastic elastomer (TPE) as the primary, solvent-debindable component in the binder system, with a 50 and 55 vol% aluminium (Al) powder content. PLA was selected due to its lower degradation temperature and to try to increase the sustainability of the MMEX process. An initial experimentation with various TPEs, employing thermal analysis (TGA and DSC), rheological behavior assessment, mechanical property testing, contact angle measurement, and solvent debinding processes, aimed to identify the most suitable TPE for this study. The results demonstrated that a very low interfacial tension between PLA and TPE is not desirable, as it may result in the removal of some powder particles during the solvent-debinding process. The TPE type with lower viscosity, optimum interfacial tension with PLA, low residue after degradation, adequate rigidity, and flexibility is proper for use as the soluble part of the binder system. After selecting of the appropriate TPE, the printability at a nozzle temperature of 270 °C was undertaken. The solvent debinding process for printed samples was conducted at room temperature. The results indicated that 90 wt% of the TPE was removed successfully from the samples printed with 30 vol% PLA in binder formulation without any defects during solvent debinding.

AB - Metal material extrusion (MMEX) involves the systematic deposition of material layer by layer, followed by debinding and sintering to produce fully dense metallic parts. The feedstocks, initially comprising metal powder and a binder system, are pivotal in determining processability and final properties. This study utilized polylactic acid (PLA) as the backbone and a thermoplastic elastomer (TPE) as the primary, solvent-debindable component in the binder system, with a 50 and 55 vol% aluminium (Al) powder content. PLA was selected due to its lower degradation temperature and to try to increase the sustainability of the MMEX process. An initial experimentation with various TPEs, employing thermal analysis (TGA and DSC), rheological behavior assessment, mechanical property testing, contact angle measurement, and solvent debinding processes, aimed to identify the most suitable TPE for this study. The results demonstrated that a very low interfacial tension between PLA and TPE is not desirable, as it may result in the removal of some powder particles during the solvent-debinding process. The TPE type with lower viscosity, optimum interfacial tension with PLA, low residue after degradation, adequate rigidity, and flexibility is proper for use as the soluble part of the binder system. After selecting of the appropriate TPE, the printability at a nozzle temperature of 270 °C was undertaken. The solvent debinding process for printed samples was conducted at room temperature. The results indicated that 90 wt% of the TPE was removed successfully from the samples printed with 30 vol% PLA in binder formulation without any defects during solvent debinding.

KW - Aluminium feedstock

KW - Contact angle

KW - Fused filament fabrication (FFF)

KW - MMEX

KW - Polylactic acid (PLA)

UR - http://www.scopus.com/inward/record.url?scp=85201012989&partnerID=8YFLogxK

U2 - 10.1016/j.rineng.2024.102692

DO - 10.1016/j.rineng.2024.102692

M3 - Article

AN - SCOPUS:85201012989

VL - 23.2024

JO - Results in Engineering

JF - Results in Engineering

SN - 2590-1230

IS - September

M1 - 102692

ER -