Enhanced Feedstock Processability for the Indirect Additive Manufacturing of Metals by Material Extrusion through...

Area of Science:

• Additive Manufacturing
• Materials Science
• Polymer Engineering

Background:

• Filament-based material extrusion (MEX) is a common additive manufacturing technique for polymers.
• Highly filled polymer filaments enable metal part fabrication through multi-step MEX processes.
• Challenges include contradictory requirements across processing steps, particularly low viscosity and sufficient ductility.

Purpose of the Study:

• To investigate the impact of ethylene-propylene copolymers (EPCs) with varying ethylene content on feedstock ductility.
• To enhance filament processability for highly filled materials in MEX.
• To optimize the additive manufacturing of metal parts using improved feedstock.

Main Methods:

• Evaluation of feedstock materials with different EPCs regarding mechanical, thermal, and debinding properties.
• Assessment of filament processability using MEX.
• Analysis of the influence of ethylene content on ductility, flexibility, and crystallization behavior.

Main Results:

• Increased ethylene content in EPCs significantly improves feedstock ductility and filament flexibility.
• Higher ethylene content influences the crystallization behavior of the feedstock material.
• An ethylene fraction of 12% in EPCs was identified as optimal for MEX processability and subsequent metal part fabrication.

Conclusions:

• Ethylene-propylene copolymers effectively enhance the ductility and processability of highly filled filaments for MEX.
• Optimizing EPC ethylene content is crucial for successful additive manufacturing of metal parts.
• The study provides a pathway for improved feedstock development in metal additive manufacturing.