Tennessee Researchers Analyze Low-Cost Metal 3D Printing with Composites

Tennessee researchers have come together to pursue a more in-depth look at the science of 3D printing with metal, outlining their findings in the recently published ‘Dimensional Analysis of Metal Powder Infused Filament – Low Cost Metal 3D Printing.’

While fused filament fabrication (FFF) is one of the most standardized, and popular, forms of 3D printing today, there are still myriad challenges for users, depending on a range of projects and their respective requirements. In this study, the researchers added a unique twist by adding a small amount of PLA to metal powder, creating a composite that is still 90 percent metal, contributing to the process presented by the researchers: metal FFF (MFFF).

FFF 3D printing platform

In using MFFF, metal-polymer composite parts can be created—while afterward sintered (heated to near melting) to remove the polymers, resulting in all-metal, and notably, creating the potential for ‘superior part complexity.’

MFFF using MPLA material

The filament used in this study, referred to as MPLA (metal powder polymer composite material) offers superior composition, presenting a material that can be used with very little alteration to normal parameters for printing with the base matrix polymer.

“The settings that need to be modified are 100% infill, a decrease in printing speed (around 20 mm/s), and an increase in material flow (around 110%). Printing parameters can be further tuned with settings such as retraction and fan speed; however, the three aforementioned settings have the most influence on the printability of MPLA,” explain the researchers.

Description of the time and temperature sweeps used for the sintering process

The post-printing process involves high temperatures, requiring a kiln to complete the all-metal part, including:

• Crucible – suspends the specimen and refractory ballast
• Refractory ballast
• Furnace capable of 1200 C

Post-processing with metal 3D printing can be complex as industrial users must then eliminate traces of oxidation, plus any sources of contamination; in studying metal composites made up of a copper/polymer combination for this project, the researchers noted that in post-processing, copper oxide was not included. They also refer to past research noting that 3D printing with metal commonly produces defects resulting in ‘a loss of stress that the fabricated parts can withstand.’ Such processes require expense and added hours though.

“The current techniques that are able to utilize FFF technology for fabricating metal parts is indirect metal fabrication,” explain the researchers. “Through the process of casting, patterns and sand-formed parts can be indirectly formed using 3D printed parts that are used to generate a mold. These techniques encompass all of the expenses and safety requirements associated with casting to fabricate parts.”

The most common metal 3D printing techniques include SLM and DMD, along with the use of other composites created with nylon, ABS, and more.

“With a minimum dimensional loss of approximately 5%, the printing and sintering procedures could be tuned to acceptable levels for a specific application. These results solidify MFFF as a possible method of M3DP for future industrial and academic applications. Further work will examine the mechanical and microstructural properties to better account for the expected behavior of MFFF fabricated parts.”

3D printing in metal continues to expand for users, mainly within heavy industrial use, and the study of composites continues too, from carbon fibers to the use of wood, the creation of a variety of nanocomposites, and more. What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.