Study reviews sustainable binders for Metal Injection Molding
Brazilian researchers from the Instituto Federal de Educação, Universidade do Recôncavo da Bahia, and Universidade Federal do Rio Grande do Sul have published research in The International Journal of Advanced Manufacturing Technology examining the current state of sustainable binder systems for Metal Injection Moulding of AISI 316L stainless steel. While MIM is already a mature manufacturing technology for the alloy, they argue that environmentally sustainable binder development remains at an exploratory stage, limiting wider industrial implementation.
The review assesses how powder characteristics, feedstock formulation, rheological behaviour, injection moulding, debinding strategies and sintering conditions interact to influence process stability and the quality of finished components. Rather than treating these stages independently, the researchers highlight the importance of understanding the relationships between them when designing new feedstocks.
Particular attention is given to bio-based and rubber-based binder systems, which have the potential to reduce the environmental impact of MIM while maintaining suitable processing characteristics. The paper examines how binder composition influences key rheological properties, including viscosity, yield stress and viscoelastic behaviour, and how these properties affect flow stability and the formation of injection moulding defects.
The review also considers solvent and thermal debinding, describing how diffusion kinetics, pore network evolution and structural integrity are closely linked during binder removal. According to the authors, these mass transport mechanisms directly influence densification during sintering and the resulting microstructure of the finished component.
Although research into sustainable binders has increased in recent years, the authors conclude that current studies remain fragmented, with binder chemistry, rheology, debinding and sintering often investigated in isolation. This limits the ability to predict or control defects such as flow instability, density variation and dimensional inconsistencies.
Instead, they propose a process-oriented framework that integrates material design with flow behaviour, mass transport and microstructural evolution throughout the MIM process. Such an approach, they suggest, would enable more predictive process design while supporting the reliable industrial implementation of environmentally sustainable feedstocks.
The authors conclude that establishing this integrated framework is an important step not only towards the wider adoption of sustainable binder systems, but also towards more robust, defect-tolerant Metal Injection Molding processes.
‘Sustainable binder systems for Metal Injection Molding of AISI 316L stainless steel: a process-oriented review’ is available here.
