Thermal Debinding for Binder Burnout in Metal and Ceramic Processing

Abstract

Sacrificial polymeric binders along with metal or ceramic powder are used for shaping the components known as green parts. Debinding process removes the sacrificial polymers from the green parts and subsequent sintering produces completely solid and dense metal/ceramic components. The Shaping, Debinding, and Sintering (SDS) technique enables the highly precise fabrication of complicated structures from materials with poor machinability. Thermal debinding is the most popular method for binder burnout, involving heating of the green parts in a suitable gaseous atmosphere. Debinding is the most critical process in the SDS where an inappropriate burnout cycle can cause cracks, blistering, swell, distortion, or breaking of components. Additionally, ineffective debinding leaves residual binder in the final component, changing the component’s properties. The understanding of various polymer burnout events has advanced significantly over the past few decades, leading to a significant improvement in the debinding process. This review provides an overview of the research done on the thermal debinding process for SDS (mainly employing material extrusion based additive manufacturing and injection molding for shaping of green parts) and suggests recommendations for future research in this field.