Bending Properties of Lightweight Copper Specimens with Different Infill Patterns Produced by Material Extrusion Additive Manufacturing, Solvent Debinding and Sintering

Abstract

Material extrusion additive manufacturing (MEX) is a versatile technology for producing complex specimens of polymers, ceramics and metals. Highly-filled filaments composed of a binder system and a high-volume content of sinterable powders are needed to produce ceramic or metal parts. After shaping the parts via MEX, the binder is removed and the specimens are sintered to obtain a dense part of the sintered filler particles. In this article, the applicability of this additive manufacturing process to produce copper specimens is demonstrated. The particular emphasis is on investigating the production of lightweight specimens that retain mechanical properties without increasing their weight. The effect of infill grades and the cover presence on the debinding process and the flexural properties of the sintered parts was studied. It was observed that covers could provide the same flexural strength with a maximum weight reduction of approximately 23%. However, a cover on specimens with less than 100% infill significantly slows down the debinding process. The results demonstrate the applicability of MEX to produce lightweight copper specimens.

A Review on Material Extrusion Additive Manufacturing of Metal and How It Compares with Metal Injection Moulding

“…Nonetheless, this issue still needs further systematic investigation to understand the effects of different infill patterns on properties in relation to other metal MEX operating variables. In addition, tensile, compressive and flexural strengths tend to decrease with decreasing the infill density, as reported by Ait-Mansour et al [53], Gonzalez-Gutierrez [90] and Rosnitschek [98].…”

“…Therefore, it can be speculated that in the case of 100% infill with suitable printing parameters to create the fully dense part, the mechanical properties can be at a similar level although the infill patterns are different. However, in the case of low infill density for weight reduction, the mechanical properties could be significantly different, as reported by Gonzalez-Gutierrez [90]. For example, the flexural strength of 50% infill density of specimens printed with diagonal and linear infill patterns is similar but significantly higher than hexagonal.…”

“…The infill patterns that have been commonly used in metal MEX are rectilinear and concentric, as listed in Table 4. There is only one study reported by Gonzalez-Gutierrez et al [90] focusing on the effects of an infill pattern in metal MEX parts. It is found that the diagonal infill pattern and the linear with 0 • , 0 • /90 • and 90 • infill pattern have no significant difference on the flexural properties and density.…”

Metal fused filament fabrication of the nickel-base superalloy IN 718

“…Finally, feedstock filaments were produced in a single screw extruder (FT-E20T-MP-IS, Dr. Collin GmbH, Germany). A detailed process description is provided in [13,14,23].…”

“…The metal fused filament fabrication (MF 3 ) has been investigated as an extension of the MIM process for free-form fabrication for a variety of metals [10][11][12][13][14]. During shaping, a green body is produced consisting of IN 718 powder particles and an organic binder.…”