Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Additive Manufacturing of Copper by 3D Extrusion
Submission Author:
Camila Gonçalves , RS
Co-Authors:
Camila Gonçalves, Manuela Furlani da Silva Soares, Milene Follmann, Natalia Daudt
Presenter: Camila Gonçalves
doi://10.26678/ABCM.COBEM2023.COB2023-1314
Abstract
In this work, pure copper samples were produced by 3D extrusion of highly viscous pastes and, as a reference, by cold-compaction. 3D extrusion of pastes is a route initially developed for ceramic fabrication and is currently investigated for metal manufacturing. This innovative technique enables the fabrication of metallic materials with significant advantages to the industry, especially by assembling higher complexity and better-functioning components, with lower potential failure from joints and reduced material waste. Shaping green parts and then sintering, instead of the fusion-based printing techniques, has been shown to provide a homogeneous microstructure with isotropic properties. In this project, the copper powder was mixed with a binder solution to form metallic pastes. Five compositions were tested, using different aqueous solutions as binders (carboxymethylcellulose, polyvinyl alcohol, and polyethylene glycol) and varying powder/liquid mass ratio from 88/12 to 60/40. The cold-compaction approach allowed for determining the best paste composition to achieve a printable texture and desirable final properties. It consists of paste deposition in a cylindrical mold and compression under high uniaxial pressure. In the 3D-printing technique, the prototype is autonomously created from a Computer-Aided Design by paste extrusion. This method tolerates a lower range of density and viscosity of the paste, as it requires a texture that allows layering. In both cases, thermal treatment was applied to the green samples to remove the binder and to sinter, bonding the copper particles. Sintering parameters, such as temperature, were tested in a range above 900°C and below 1000°C. The volumetric retraction due to sintering is highlighted as a crucial parameter for piece dimensioning. Once produced, the samples received a metallographic preparation and were characterized concerning crystallography, porosity, microstructure, Vickers microhardness, and compressive strength. This microstructural investigation enables comparison between printed and compacted samples and among different pastes, while also providing an insight into the potential of 3D extrusion-based Additive Manufacturing.
Keywords
Additive manufacturing, 3D extrusion, Cold-compaction, Copper, Microstructural investigation
