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Interaction between Binder and Powder in Injection Moulding of 316L Stainless Steel

Owing to several steps involved in metal injection moulding (MIM) process, it is important to understand the interactions between metal powder and binder mixture particularly during mixing, injection moulding and debinding. A polar organic compound generally forms hydrogen bonds more readily with metal powder because of acid-base interactions. In this study, the interaction of local binder system comprised of; palm stearin (PS) and thermoplastic natural rubber (TPNR) with conventional binder; polyethylene (PE), polypropylene (PP) and paraffin wax (PW) and mixed with 316L stainless steel powder were investigated. The results showed that all the binder have high interaction with 316L stainless steel that make, the resulting the bonding sufficiently strong and suitable for MIM process. Keywords: Chemical interaction, Injection Moulding, Binder, Rheology

Sintering Characteristics of Injection Moulded 316L Component Using Palm-Based Biopolymer Binder

Metal injection moulding (MIM) has been widely recognised as an advanced technology for the fabrication of complex-shaped, low cost and high performance components. Fine powders, less than 20 micron in diameter, are mixed with suitable thermoplastic binder and formed into the desired shapes. The binder aids the flowability and formability of fine metal powders during moulding, and they have to be removed in the next stage to enable high density components to be produced. The removal of the binder is done either thermally in the furnace or by solvent extraction. Ideally, the removal of the binder would open up pore channels which allow accelerated removal of the higher boiling point components. The components are sintered following the debinding stage. This stage is crucial to the MIM process as appropriate sintering conditions would ensure pore-free structures that have good mechanical properties (German, 1990; German and Bose, 1997)

Development of Metal Injection Moulding Process for Medical Applications

To counter the problems associated with the conventional processes of producing implants, a new approach has been invented, which is the adaptation of the injection moulding process for manufacturing the fracture fixation plates. With this technique in place, we have now taken a step in the right direction towards rapid manufacturing of fracture fixation plates, for the first time. The fracture fixation plates produced using this technique comply with the international standards including MPIF Standard 35, ISO 5832-1 and ISO 10933. The advantages of the present invention are design flexibility, rapid manufacturing, cost effectiveness and minimal waste compared to conventional process

Rheological Properties of Hydroxyapatite Synthesized Clamshell Mix with Palm Stearin Binder System

This study investigated the flow behavior of feedstock containing hydroxyapatite (HAp) powder with palm stearin (PS) based binder system. The HAp was synthesized via chemical precipitation method with the use of waste of clamshells. The result showed that single phase synthesized HAp was successfully formed at annealing temperature and pH solution of 850°C and 6.5, respectively. The synthesized HAp with a volume fraction of 65% was then mixed with PS and and Polyethylene binder at 160°C to prepare a feedstock. From the rheological test result, it was found that the feedstock exhibited a pseudoplastic behavior with low values of shear sensitivity in comparison with commercial HAp.