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Princeton, NJ, United States

Shivashankar T.S.,Indo-MIM | Enneti R.K.,Global Tungsten Powders | Park S.-J.,Pohang University of Science and Technology | German R.M.,San Diego State University | Atre S.V.,Oregon State University
Powder Technology | Year: 2013

The composition of the powder-binder mixture (feedstock) used in powder injection molding (PIM) plays a crucial role in fabricating defect-free parts. Powder-binder separation in the feedstock during mixing or molding is responsible for defects such as voids, cracks, or distortion in the sintered part. This study introduces an inter-particle spacing parameter, δ, based on particle size (D), particle volume fraction (φ) and maximum particle fraction (φm). The derived parameter is investigated using feedstocks prepared from three different metal powders. Based on comparisons with experimental data from this study as well as reports in the literature, the inter-particle spacing parameter, δ, proves to be a useful predictor of powder-binder separation. The newly proposed parameter assists in designing and developing feedstocks to manufacture components by PIM. © 2013 Elsevier B.V. Source

Enneti R.K.,Global Tungsten Powders | Shivashankar T.S.,Indo-MIM | Park S.-J.,Pohang University of Science and Technology | German R.M.,San Diego State University | Atre S.V.,Oregon State University
Powder Technology | Year: 2012

This study successfully extends the master sintering curve concept to model removal of polymeric binders in powder injection molded bodies. In this demonstration the focus is solvent debinding. Master debinding curves (MDC) were used to estimate the activation energy for debinding. Binder removal curves were developed for solvent extraction of polyethylene glycol (PEG) from injection molded shapes made from silicon nitride doped with yttria and spinel (Si 3N 4 5% Y 2O 3 5% MgAl 2O 4). The extraction for different shapes incorporated a shape parameter in the standard master curve equation, giving activation energy of 12.4kJ/mol extraction of PEG. Master debinding curves were also developed for wicking debinding. The analysis showed lower activation energies for solvent extraction and wicking compared to thermal debinding. The lower activation energy suggests easier removal by solvent or wicking versus pyrolysis. The study provides a unifying quantitative framework for comparing and predicting the effects of material, process and geometry on binder removal. The master debinding curves can be utilized in design and optimization of binder removal. © 2012. Source

Indo-MIM | Entity website

Hindistan, Bangalorede bulunan Indo-MIM, ekirdek retim teknolojisi olarak, metal enjeksiyon kalplama (MIM) tekniini kullanarak hassas mhendislik rnlerinin, dnya lideri tedarikisidir. MIM prosesi, plastik enjeksiyon kalplama tekniinin esnekliiyle dvme metalin mukavemetinin bir kombinasyonu olarak ok kompleks para geometrileri iin ekonomik zmler sunar ...

Indo-MIM | Entity website


Mukund B.N.,Indo-MIM | Shivashankar T.S.,Indo-MIM
International Powder Metallurgy Congress and Exhibition, Euro PM 2013 | Year: 2013

The powder-binder composition in a feedstock used for powder injection molding (PIM) plays a crucial role in manufacturing distortion free products out of sintering. This study successfully demonstrates the application of 'interparticle spacing parameter, δ' to model shape retention (distortion) of a powder injection molded (PIM) feedstocks in sintering. The powders used in the study are Carbonyl iron powder with 2% Ni (CIP), Cobalt based Co-400 (Co-400) and 17-4PH Stainless Steel (SS) alloying composition. 'Interparticle spacing parameter, δ' of CIP, Co-400 and 17-4PH SS powder differing in powder morphology and mean particle size was investigated. The binder system considered for the study is wax-polymer system. The experimental data from this study, suggests the 'interparticle spacing parameter, δ', proves to be a useful predictor of shape retention of PIM components. The reports in the literature and also based on the experimental data in the present work using Capillary Rheometer and Pycnometer the 'Interparticle spacing parameter, δ' is also a useful predictor of powder-binder separation. An optimum region has been proposed which assists in designing defects and distortion free feedstock formulation right at first time to manufacture components by PIM without resorting to trial-and-error practices currently prevalent in the industry. Source

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