Abstract

The influence of temperature and powder loading on the Metal Injection Moulding (MIM) green compact is presented. The feedstock used is a mixture of stainless steel (SS316L) powder and a composite binder system consisting of polyethylene glycol (PEG) and polymethyl methacrylate (PMMA). The bi-modal particle size distribution powder has a composition of 30 and 70% by weight of fine and coarse SS316L powder respectively with a powder loading of 64 and 65% by volume. The Battenfeld BA 250 CDC injection-moulding machine was used to produce a MIMA tensile specimen. The as-moulded density was measured using the Archimedes water immersion method according to the MPIF Standard 42. The injection temperature was varied from 120 to 150°C while the injection pressure remains at 350 bars. The three-point bending test was performed using INSTRON 5567 to measure the green strength according to the MPIF Standard 15. Results showed that the bi-modal feedstock with the higher powder loading was more sensitive to temperature and that the injection temperature was less significant to the as-moulded strength and density.

Keywords: Metal injection moulding, bi-modal, particle size distribution, density, green strength, powder loading.

Abbreviation

MIM, Metal Injection Moulding; PEG, polyethylene glycol; PMMA,polymethyl methacrylate; SA, stearic acid