TY - JOUR

T1 - Comparative analysis of binder systems in copper feedstocks for metal extrusion additive manufacturing and metal injection moulding

AU - Sadaf, Mahrukh

AU - Cano Cano, Santiago

AU - Bragaglia, Mario

AU - Schuschnigg, Stephan

AU - Kukla, Christian

AU - Holzer, Clemens

AU - Vály, Lilla

AU - Kukla, Christian

AU - Kitzmantel, Michael

AU - Nanni, Francesca

AU - Gonzalez-Gutierrez, Joamin

N1 - Publisher Copyright: © 2024 The Authors

PY - 2024/2/21

Y1 - 2024/2/21

N2 - In the realm of material innovation, the remarkable versatility of thermoplastic-based highly filled composites emerges as a pivotal advantage for fabricating metal parts, seamlessly integrating design flexibility. This study delves into the fusion of design and manufacturing, spotlighting the convergence of material extrusion additive manufacturing (MEX) and metal injection moulding (MIM) processes through the adept utilization of three distinct in-house developed copper-feedstocks. Each feedstock had a different composition that influenced their processability; two feedstocks were for solvent and thermal debinding, and one was only for thermal debinding. The sintering was carried out under the same conditions for all produced specimens to assess the effect of binder composition on the properties of the sintered components. Structural integrity evaluations of sintered specimens encompassed 3-point bending, hardness tests, and metallography. It was possible to perform MEX with all produced filaments and MIM with the pellets of the same feedstocks and to obtain acceptable-quality specimens. Regardless of the shaping method, specimens shaped with binders containing a soluble binder survived the thermal and sintering steps. The specimens produced from the feedstock intended solely for thermal debinding experienced a nearly complete loss of shape during the debinding process. For the specimens that could be debound and sintered without defects, a relative density between ∼88 and 94 % was measured for MEX components and ∼93 and 95 % for MIM components after sintering. All sintered components showed the same diffraction peaks as pure copper powder, confirming that the reductive hydrogen atmosphere provided protection from contamination and reduced the oxides that could have appeared during thermal debinding in air. Moreover, adequate shrinkage of ∼10–18 % was observed in the sintered specimens. Vickers microhardness of the MEX and MIM sintered components were ∼32 HV and ∼36 HV, respectively. Compared to MEX, MIM-produced sintered components showed a higher maximum stress (i.e., σmax = 79 ± 3.2 MPa). These results demonstrate that the binder composition plays a crucial role in determining the success of metal MEX and MIM processes. Having the possibility to choose between MEX and MIM allows for greater design flexibility for copper parts.

AB - In the realm of material innovation, the remarkable versatility of thermoplastic-based highly filled composites emerges as a pivotal advantage for fabricating metal parts, seamlessly integrating design flexibility. This study delves into the fusion of design and manufacturing, spotlighting the convergence of material extrusion additive manufacturing (MEX) and metal injection moulding (MIM) processes through the adept utilization of three distinct in-house developed copper-feedstocks. Each feedstock had a different composition that influenced their processability; two feedstocks were for solvent and thermal debinding, and one was only for thermal debinding. The sintering was carried out under the same conditions for all produced specimens to assess the effect of binder composition on the properties of the sintered components. Structural integrity evaluations of sintered specimens encompassed 3-point bending, hardness tests, and metallography. It was possible to perform MEX with all produced filaments and MIM with the pellets of the same feedstocks and to obtain acceptable-quality specimens. Regardless of the shaping method, specimens shaped with binders containing a soluble binder survived the thermal and sintering steps. The specimens produced from the feedstock intended solely for thermal debinding experienced a nearly complete loss of shape during the debinding process. For the specimens that could be debound and sintered without defects, a relative density between ∼88 and 94 % was measured for MEX components and ∼93 and 95 % for MIM components after sintering. All sintered components showed the same diffraction peaks as pure copper powder, confirming that the reductive hydrogen atmosphere provided protection from contamination and reduced the oxides that could have appeared during thermal debinding in air. Moreover, adequate shrinkage of ∼10–18 % was observed in the sintered specimens. Vickers microhardness of the MEX and MIM sintered components were ∼32 HV and ∼36 HV, respectively. Compared to MEX, MIM-produced sintered components showed a higher maximum stress (i.e., σmax = 79 ± 3.2 MPa). These results demonstrate that the binder composition plays a crucial role in determining the success of metal MEX and MIM processes. Having the possibility to choose between MEX and MIM allows for greater design flexibility for copper parts.

KW - Additive manufacturing

KW - Copper

KW - Debinding

KW - Material extrusion (MEX)

KW - Metal injection moulding (MIM)

KW - Sintering

KW - Feedstock

KW - Copper

KW - Polymer processing

KW - Material Extrusion

KW - Additive Manufacturing

UR - http://www.scopus.com/inward/record.url?scp=85186267664&partnerID=8YFLogxK

U2 - 10.1016/j.jmrt.2024.02.163

DO - 10.1016/j.jmrt.2024.02.163

M3 - Article

AN - SCOPUS:85186267664

VL - 29.2024

SP - 4433

EP - 4444

JO - Journal of Materials Research and Technology

JF - Journal of Materials Research and Technology

SN - 2238-7854

IS - March-April

ER -