Advancing Powder-Binder Formulations for Additive Manufacturing

Adapting MIM Materials for Sinter-Based AM Technologies

MTC partnered with CMG to assess the suitability of a 17-4 PH MIM formulation for Fused Granulate Fabrication (FGF), including compounding and an initial evaluation of printability and material performance.

The Challenge

CMG Technologies, a subsidiary of Indo-MIM—the world’s leading specialist in Metal Injection Moulding (MIM)—develops feedstocks and components using sinter-based technologies, including MIM and Material Extrusion Additive Manufacturing (MEX).

CMG sought to evaluate whether their 17-4 PH feedstock, originally developed for MIM, could be effectively processed using Fused Granulate Fabrication (FGF)—a MEX process that utilises granulated feedstocks. This investigation aimed to assess the feasibility of adapting existing materials for FGF and to explore potential new market opportunities.

FGF systems operate similarly to Fused Filament Fabrication (FFF) but use granulate-form feedstock instead of filament. This approach enables the processing of a wider range of materials, including those formulated for MIM, while also reducing the time and cost associated with feedstock preparation.

MTC's Solution

MTC leveraged its advanced materials processing expertise to compound and pelletise a batch of CMG’s 17-4 PH feedstock. This was achieved using a twin-screw extruder, a unique system designed specifically to handle high-wear materials at elevated temperatures, making it ideally suited for processing metal-loaded formulations.

Following compounding, a preliminary printability assessment was conducted using MTC’s in-house Fused Granulate Fabrication (FGF) platform, the ExAM 255. This system features a twin-hopper configuration capable of processing granulated feedstocks, including polymers, metals, and ceramics. Its flexibility and robust material handling capabilities made it an ideal platform for evaluating the performance of CMG’s pelletised feedstock in an additive manufacturing context.
 

The Outcome

• Following parameter optimisation on the twin-screw extruder, visual inspection of the pelletised material indicated good uniformity and homogeneity. This was supported by SEM analysis, which confirmed a well-dispersed distribution of metallic particles.
   
• Test coupons were successfully printed using the ExAM 255, demonstrating the material’s promising potential for FGF processing.
   
• Further printing, post-processing, and application testing by third parties, along with optical microscopy analysis of a sintered demonstrator at MTC, also indicated strong early performance of the material for FGF applications.
   

Benefits to the Client

• This case study highlights the potential of CMG’s 17-4 PH MIM formulation as a viable feedstock for FGF processes.
   
• The results lay a strong foundation for further development and optimisation of CMG’s MIM feedstocks for additive manufacturing applications.
   
• Demonstrating the feasibility of FGF printing with these materials could open new market opportunities for CMG.
   
• Moreover, this work showcases how MTC’s expertise in materials processing and compounding can support industry partners in evaluating and advancing new formulations for FGF, accelerating innovation in the sinter-based additive manufacturing space.