A Review of Fused Filament Fabrication of Metal Parts (Metal FFF): Current Developments and Future Challenges

by Tanya Fosdal | Dec 19, 2024 | research papers

“Fused filament fabrication (FFF) is the most widespread and versatile material extrusion
(MEX) technique. Although powder-based systems have dominated the metal 3D printing landscape
in the past, FFF’s popularity for producing metal parts (“metal FFF”) is growing. Metal FFF starts from
a polymer–metal composite feedstock and proceeds through three primary stages, namely shaping
(i.e., printing), debinding, and sintering. As critically discussed in the present review, the final quality
of metal FFF parts is influenced by the characteristics of the composite feedstock, such as the metal
loading, polymer backbone, and presence of additives, as well as by the processing conditions. The
literature shows that a diverse array of metals, including steel, copper, titanium, aluminium, nickel,
and their alloys, can be successfully used in metal FFF. However, the formulation of appropriate
polymer binders represents a hurdle to the adoption of new material systems. Meanwhile, intricate
geometries are difficult to fabricate due to FFF-related surface roughness and sintering-induced
shrinkage. Nonetheless, the comparison of metal FFF with other common metal AM techniques
conducted herein suggests that metal FFF represents a convenient option, especially for prototyping
and small-scale production. Whilst providing insights into the functioning mechanisms of metal FFF,
the present review offers valuable recommendations, facilitating the broader uptake of metal FFF
across various industries.”

A Review of Fused Filament Fabrication of Metal Parts (Metal FFF) Current Developments and Future Challenges Download

Paper published to MDPI on 19 December 2024 https://www.mdpi.com/2227-7080/12/12/267

Understanding the Fused Filament Fabrication Process

The Fused Filament Fabrication (FFF) process for metal parts involves a series of critical stages that ensure high-quality outcomes. Initially, a polymer-metal composite feedstock is shaped through the printing stage, where the material is extruded layer by layer to form the desired object. This is followed by debinding, which removes the polymer component, and finally sintering, where the metal particles are fused together at high temperatures to achieve the final density and strength.

This multi-stage process is essential for achieving the desired mechanical properties and surface finish of the printed metal parts. Factors such as the choice of polymer, metal loading within the composite, and the specific conditions during debinding and sintering significantly affect the final product. For instance, using a high metal loading can enhance strength but may complicate the debinding process.

Applications of Metal FFF in Various Industries

Metal FFF technology has found applications across a wide range of industries, including aerospace, automotive, and medical sectors. Its ability to produce complex geometries and lightweight components makes it particularly valuable in industries where performance and efficiency are paramount. For example, aerospace manufacturers are utilizing metal FFF to create intricate engine components that reduce weight without sacrificing strength.

Moreover, the medical industry benefits from metal FFF through the production of customized implants and surgical tools tailored to individual patient needs. The flexibility of the technology allows for rapid prototyping and production, enabling faster innovation cycles and the ability to meet specific regulatory requirements without extensive retooling.

Challenges and Limitations of Metal FFF Technology

Despite its advantages, metal FFF technology faces several challenges that can hinder its widespread adoption. One significant limitation is the variability in part quality, which can be influenced by factors such as feedstock consistency and environmental conditions during printing. Inconsistent results can lead to concerns regarding reliability and safety in critical applications.

Additionally, the sintering stage presents challenges, as achieving the optimal temperature and time is crucial for ensuring proper bonding of metal particles. Overcoming these challenges requires ongoing research and development to refine the technology and establish best practices that can enhance the reliability and performance of metal FFF parts.

Future Trends in Metal 3D Printing Technologies

The future of metal 3D printing, particularly through FFF, is poised for significant advancements as research continues to evolve. Innovations in materials science are expected to yield improved composite feedstocks that enhance printability and part performance. Furthermore, advancements in process control and monitoring technologies will likely lead to greater consistency and quality in printed parts.

As industries increasingly embrace additive manufacturing, the integration of artificial intelligence and machine learning into the metal FFF process could optimize production parameters in real-time, reducing waste and improving efficiency. This shift towards smarter manufacturing practices is likely to drive broader adoption of metal FFF technology across various sectors.