Evaluation of porosity in metal injection

Metal Injection Moulding (MIM) is more like plastic injection moulding but with metals. Lubricated metal powder are prepared with a thermoplastic binder, and moulded in an injection moulding machine into a mould that is very similar to a normal injection mould [1]. After moulding, the “green compacted” moulding material is sent through a debinding process and then through a sintering process. MIM is capable of producing in both large and small volumes, complex shapes and from almost all types of material including metals, ceramics, inter-metallic, compounds, and composites. With no official binder and also exact value for green optimal criteria in MIM, the process for MIM using powder far from been using massively in machining industries [2][3]. In this study, the 60% of Stainless Steel (SS316L) powder loading with binder ratio 50/50 of sewage fat or fats, oil and grease (FOG) and Polypropylene (PP) will be use and analyse for optimal injection and binder parameter. The objective is to determine the porosity and crack at the surface of the brown part using Non-Destructive Test (NDT) process. The percentage of weight loss after solvent and thermal debinding process also have been identified. Hexane has been used as the solvent to remove binder in solvent debinding process. Moreover, the best temperature for hexane to remove binder in sample has been identified which is 50 ˚C of hexane has been picked as the best temperature compared to 40 ˚C of hexane. Thermal debinding has been used to remove Polypropylene (PP) in sample. Both temperature for thermal debinding has been tested which is 40 ˚C and 50 ˚C. The best temperature for thermal debinding is 400 ˚C because it will produce higher percentage of ferum but lower percentage of oxygen. Forming less number of oxygen content will prebent oxidation on sample.