Metal Injection Molding (MIM) is a manufacturing technique for complex and small-sized components. The process consists of mixing the metal, in powder form, with a combination of polymers (binder system) to produce the "feedstock". The "feedstock" is molded using a conventional plastic injection machine to obtain the desired geometry. Once the part is molded, the binder system is removed and the part is sintered, which will give rise to a final part with properties comparable to those obtained by other conventional procedures. This technique, compared to other conventional methods such as forging or powder metallurgy, allows to obtain parts with complex geometries without secondary operations [1,2].

A typical binder system used in MIM is formed by a combination of a thermoplastic polymer, like polyethylene (PE) or polypropylene (PP) and a wax or oil. The thermoplastic polymer provides stability and resistance to the molded part while the wax or oil decreases the viscosity of the mixture to favor molding [3–5].

The main objective of this work is to understand the interactions and behavior of polyethylene and paraffin mixtures. For this purpose, the interaction of mixtures of different types of PE and different waxes has been studied in order to carry out a systematic study of the compatibility of these materials, and to have a better understanding of their behavior. Molecular dynamics simulations were used to study the miscibility of the mixtures. In addition, mixtures of different compositions have been prepared using polyethylene and wax with different characteristics. These mixtures have been characterized through thermal analysis to study their thermal characteristics and the interactions between the components.

References

[1] R.M. German; Metal Injection Molding: A Comprehensive MIM Design Guide, MPIF, Princeton, N.J., 2011.

[2] D.F. Heaney, Handbook of Metal Injection Molding, Elsevier, 2012.

[3] R.M. German, Powder injection molding: design and applications: user’s guide, Innovative Materials Solutions, State College, PA, 2003.

[4] D. Bleyan, B. Hausnerova, P. Svoboda, The development of powder injection moulding binders: A quantification of individual components’ interactions, Powder Technology, 2015, 286, 84–89.

[5] R. Supati, N.H. Loh, K.A. Khor, S.B. Tor, Mixing and characterization of feedstock for powder injection molding, Materials Letters, 2000, 46, 109–114.