Net-Shape Manufacturing of Micro Porous Metal Components by Powder Injection Molding

Abstract

A novel production method for porous metal components has been developed by applying powder space holder (PSH) method to metal powder injection molding (MIM) process. The PSH-MIM method has an industrial competitive advantage that is capable of net-shape manufacturing the micro-sized porous metal products with complicated shapes and controlled porosity and pore size. In this study, the small impeller with homogeneous micro-porous structure was manufactured by the PSH-MIM method using porous compounds composed of fine stainless steel 316L powder and polymethylmethacrylate (PMMA) particle. The effects of combinations in size and fraction of PMMA particle on dimensional tolerance and variation of sintered porous specimens were investigated. It was concluded that the PSH-MIM method could manufacture commercially micro-porous metal components with high dimensional accuracy.

Injection molding of micro-porous titanium alloy with space holder technique

“…It can be seen that the samples have a homogeneous structure with open pores, which represent PMMA particle characteristics, and uniformity of mixture. It is also possible to obtain a purposely tailored distribution of the pore size in the foam by using PMMA particles with different particle size ranges [5,9]. For all samples, neck formation, which is the starting point for sintering, can be clearly seen in microstructures at 1250°C for 60 min.…”

“…In a recent study, the thermal decomposition temperature of PMMA and the best sintering temperature of mixtures of aluminum powder and PMMA powder have been optimized experimentally [4][5][6][7]. Nishiyabu et al [4][5] investigated the manufacturing parameters (size and fraction of PMMA particles and bending properties of the micro-porous graded structure) of commercial micro-porous metal components by PIM.…”

“…Nishiyabu et al [4][5] investigated the manufacturing parameters (size and fraction of PMMA particles and bending properties of the micro-porous graded structure) of commercial micro-porous metal components by PIM. Their study showed that PMMA particles can be decomposed during debinding and micro-porous metal components can be easily manufactured by PIM.…”

“…Currently, few methods can produce net-shaped metal components with high production efficiency. Furthermore, it is not easy to control the cell size and its distribution in practice and much more so to produce such micro-porous metal and ceramics components with complicated shapes and high dimensional accuracy [4][5][6].…”

“…An open cell structure is useful for applications such as heat exchangers and heat sinks for thermal management, medical implants, filters, and electrodes in biological and chemical reactions. Conventional press-sinter manufacturing methods can be used with a small subset of methods to create porous materials with a limited range of cell size and porosity [4][5]. In practical ways, it is very difficult for metals to produce controlled pore sizes in the tens of micrometers with both open and closed cell structures and specified porosity.…”