Supersonic Gas Nozzle Pressure Ratio Optimization in Powder Metallurgy
Maintaining nozzle pressure ratio within supersonic design boundaries guarantees negative tip aspiration, eliminating melt reflux and maximizing fine powder yield.
Metal Injection Molding Powder
Meaning
Fine metal particulates with high sphericity and controlled size distribution constitute the raw material for compounding into injection-moldable feedstocks. This metal injection molding powder typically has a median particle size below twenty micrometers to ensure high packing density and rapid sintering. In the compounding step, the powder is blended with thermoplastic binders before being molded into green parts.
Sintering then removes the binder and densifies the component.
Powder Characteristics
High-pressure gas or water atomization processes generate the required particle shape and size distribution for these applications. For a high-quality metal injection molding powder, a spherical morphology is preferred because it lowers the viscosity of the feedstock mix. High tap density reduces the volume of binder required, which in turn minimizes the shrinkage during the sintering step.
Low oxygen content prevents the formation of oxide boundaries that weaken the sintered metal.
Processing Performance
Compounding the powder with a polymer binder creates a feedstock that flows easily into complex mold cavities. The flow behavior during molding depends on the friction between the particles. Spherical particles slide past each other with minimal resistance.
Quality Sourcing
Sourcing decisions are based on the consistency of the particle size distribution. Large batch-to-batch variations alter the shrink factor during sintering, leading to dimensional tolerance issues.