Powder injection molding

In PIM and MIM applications, the feedstock’s rheological properties are very important because they influence the homogeneity of the molten feedstock, how well it flows through the die into the mold cavity, and the mechanical properties of the green part on cooling. These rheological properties are influenced by several factors, including the binder’s molecular weight and molecular structure, solid loading, particle size and particle shape, temperature, and flow rate. Most metals and ceramics can be used in PIM if they have the correct powder properties, including particle size and shape.

So, to produce high-quality feedstock, green parts, and ultimately final components – and to have a wide choice of materials – manufacturers must carefully characterize these properties. In particular, high packing densities are required, so spherical particles with the correct size distribution are preferable, as are smaller particles (< 38μm) that sinter more readily. Slight particle irregularity can be beneficial to give mechanical strength to green and brown parts.

Malvern Panalytical’s material characterization solutions for powder injection molding can be used to:

• Optimize particle loading to minimize part shrinkage and void formation
• Ensure appropriate feedstock rheology during molding and dimensional stability post-extrusion
• Optimize binder properties, including molecular weight and structure, for flow behavior and de-binding performance
• Ensure consistent metal powder supplies with the correct particle size, elemental composition, and microstructure