Polymer based binder materials for various metal injection molding processes: Salient aspects and recent trends

Metal injection molding (MIM) is a near-net shape manufacturing technique that was first noted in the early 1970's. Over the years, this process has distinguished itself from the other manufacturing processes in terms of the accuracy and quality of the products. It is prominent for producing parts with high relative density, nearly >95%. Today, it has a wide range of applications in the aerospace, automotive, biomedical and electronics industries. The recent developments in MIM have been regularly reviewed. However the focus on binder materials formulation for MIM is limited. The proper selection of binders for various metals and the composition of feedstock profoundly impact the quality of the components produced. In this regard, a broad study and understanding of binder materials for MIM are of extreme significance. Thus, the current work intends to provide an overview of binders used for metal injection molding based on the type of metal particles and applications. It gives an insight into the state of the art of MIM in different metals and alloys. The effect of debinding and sintering atmospheres on parts integrity is also studied. Then, it concludes with rheological characterization studies and popular optimization techniques for optimizing various process parameters in metal injection molding.