Injection moulding of porous 316L stainless steel using saccharose as a space holder material / Nurul Farhana Omar

Metal injection molding (MIM) is a manufacturing process which has promising technique as it offers several advantages in producing part. MIM route with a space holder replication was employed in this study. Saccharose as a space holder material was introduced at the stage of powder-binder mixing followed by injection moulding. 316L stainless steel (316L SS) powder, binder components (low density polyethylene, palm stearin) and two different sizes of saccharose in the range of 163 microns to 250 microns and 44 microns to 63 microns were used for this study. The mixing process involving the incorporation of the space holder was conducted and assessed at various parameters prior to solvent debinding and sintering. Flow behavior index (n), flow activation energy, E (kJ/mol) and moldability index of all feedstock with different composition had acceptable value to be implemented for injection molding process. Optimum debinding temperature chosen based on the screening test was 60°C as palm stearin was completely removed from the green part at 60°C for 5 hours with no visual defect observed on the surface of the brown part. Thermal debinding was performed at temperature of 450°C, heating rate of 1°C/min and 1 hour holding time.