Metal 3D printing is a form of component fabrication that greatly reduces the cost of manufacturing complex structures in contrast to subtractive manufacturing. Highly complex and customized designs are achieved by depositing a material layer by layer in a process called fused filament fabrication (FFF).
New research from the Tennessee public university, Tennessee Tech has found a possible way of further reducing the cost of 3D metal printing by using a new fabrication technique for FFF printing.
The technique relies on the use of a polylactic Acid (PLA)-compliant metal powder composite filament. This composite allows for a part to be made with approximately 90% metal composition and sintered. The sintering process removes the PLA bonding, leaving a 100% metal part fabricated on a low-cost FFF printer.
The metal-polymer composite filament extruded during 3D printing is composed volumetrically of approximately 90 vol% of the desired metal to be used and 10 vol% of a polymer bonding agent.
The research points out some alterations in printer parameters for this process to be effective. These parameters are, however, minimal and are based on the combined properties of the composite material.
“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.”
Most of the magic happens after the component has been printed in a sintering process. The component is heated in a furnace to a temperature close to the melting point of the metal. This allows the metal particles to fuse to each other creating strong bonds that give the object true metal tensile strength.
The sintering process also removes oxidation and contaminants from the metal part and burns off the PLA.
“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 behaviour of MFFF-fabricated parts.”
This research makes it feasible for the cost of additive manufacturing to be cut down by about 10%. That is a huge amount of money considering the amount of money companies put into additive manufacturing for components in their products.
