Molding Properties of Cobalt-Chrome-Based Feedstocks Used in Low-Pressure Powder Injection Molding

Authors: Ehsan Gholami, Vincent Demers

Abstract:

Low-pressure powder injection molding is an emerging technology for cost-effectively producing complex shape metallic parts with the proper dimensional tolerances, either in high or in low production volumes. In this study, the molding properties of cobalt-chrome-based feedstocks were evaluated for use in a low-pressure powder injection molding process. The rheological properties of feedstock formulations were obtained by mixing metallic powder with a proprietary wax-based binder system. Rheological parameters such as reference viscosity, shear rate sensitivity index, and activation energy for viscous flow, were extracted from the viscosity profiles and introduced into the Weir model to calculate the moldability index. Feedstocks were experimentally injected into a spiral mold cavity to validate the injection performance calculated with the model.

Keywords: Binder, feedstock, moldability, powder injection molding, viscosity.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1317434

References:

[1] M. Aslam, F. Ahmad, P. S. M. B. M. Yusoff, K. Altaf, M. A. Omar, H. P. S. Abdul Khalil, M. R. Raza, Investigation of Rheological Behavior of Low Pressure Injection Molded Stainless Steel Feedstocks, Advances in Materials Science and Engineering, 2016 (2016).
[2] G. Wen, P. Cao, B. Gabbitas, D. Zhang, N. Edmonds, Development and design of binder systems for titanium metal injection molding: An overview, Metall. Mater. Trans. A, 44 (2013) 1530-1547.
[3] R. Ibrahim, M. Azmirruddin, M. Jabir, N. Johari, M. Muhamad, A.R.A. Talib, Injection Molding of Inconel 718 Parts for Aerospace Application Using Novel Binder System Based on Palm Oil Derivatives, International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering, 6 (2012) 2112-2116.
[4] M. E. Sotomayor, A. Cervera, A. Várez, B. Levenfeld, Duplex Stainless Steel Self-ligating Orthodontic Brackets by Micro-powder Injection Moulding, International Journal of Engineering Research & Science, 2 (2016) 184-193.
[5] B. Hausnerova, Powder injection moulding-An alternative processing method for automotive items, InTech, 2011.
[6] D. Heaney, Woodhead Publishing, 2012, pp. 604.
[7] J. González-Gutiérrez, G.B. Stringari, I. Emri, Powder Injection Molding of Metal and Ceramic Parts, InTech, 2012.
[8] M. R. Harun, N. Muhamad, A. B. Sulong, N. H. M. Nor, M. H. I. Ibrahim, Rheological investigation of ZK60 magnesium alloy feedstock for metal injection moulding using palm stearin based binder system, Applied Mechanics and Materials, 44-47 (2011) 4126-4130.
[9] N. H. M. Nor, M. H. Ismail, N. A. Abu Kasim, N. Muhamad, M. A. Taib, Characterization and rheological studies on ready-made feedstock of stainless steel 316L in metal injection molding (MIM) process, Applied Mechanics and Materials, 465-466 (2014) 709-714.
[10] V. Demers, S. Turenne, O. Scalzo, Impact of binders on viscosity of low-pressure powder injection molded Inconel 718 superalloy, Journal of Materials Science, 50 (2015) 2893-2902.
[11] J. Hidalgo, A. Jimnez-Morales, T. Barriere, J.C. Gelin, J. M. Torralba, Capillary rheology studies of INVAR 36 feedstocks for powder injection moulding, Powder Technol., 273 (2015) 1-7.
[12] F. E. Weir, M. E. Doyle, D. G. Norton, Moldability of plastics based on melt rheology, SPE Transactions, 3 (1963) 32-41.
[13] P. Seong-Jin, W. Yunxin, D. Heaney, Z. Xin, G. Guosheng, R. German, Rheological and thermal debinding behaviors in titanium powder injection molding, Metallurgical and Materials Transactions A (Physical Metallurgy and Materials Science), 40 (2009) 215-222.
[14] C. Joon-Phil, L. Hyun-Gon, L. Won-Sik, L. Jai-Sung, Investigation of the rheological behavior of 316L stainless steel micro-nano powder feedstock for micro powder injection molding, Powder Technol., 261 (2014) 201-209.
[15] H. Abdoos, H. Khorsand, A. A. Yousefi, Torque rheometry and rheological analysis of powder-polymer mixture for aluminum powder injection molding, Iranian Polymer Journal, 23 (2014) 745-755.
[16] M. H. I. Ibrahim, N. Muhamad, A.B. Sulong, Rheological investigation of water atomised stainless steel powder for micro metal injection molding, International Journal of Mechanical and Materials Engineering, 4 (2009) 1-8.
[17] A. Ghanbari, M. Alizadeh, E. Ghasemi, R. Y. Rad, S. Ghaffari, Preparation of optimal feedstock for low-pressure injection molding of Al/SiC nanocomposite, Science and Engineering of Composite Materials, 22 (2015) 549-554.
[18] N. N. Ismail, K. R. Jamaludin, N. Ahmad, Glycerol As Plasticizer For Waste Polystyrene Based Metal Injection Molding (MIM) Binder, Advanced Materials Research, 845 (2014) 837-840.
[19] V. Demers, M. M. Elmajdoubi, P. Bocher, 2017 World Congress on Powder Metallurgy and Particulate Materials, PowderMet 2017, June 13, 2017 - June 16, 2017, Metal Powder Industries Federation, Las Vegas, NV, United States, 2017, pp. 401-414.
[20] G. C. Babis, A. F. Mavrogenis, Cobalt–Chrome Porous-Coated Implant-Bone Interface in Total Joint Arthroplasty, in: T. Karachalios (Ed.) Bone-Implant Interface in Orthopedic Surgery: Basic Science to Clinical Applications, Springer London, London, 2014, pp. 55-65.
[21] Z. Y. Liu, N. H. Loh, S. B. Tor, K. A. Khor, Characterization of powder injection molding feedstock, Mater. Charact., 49 (2003) 313-320.
[22] S. G. Lamarre, V. Demers, J.-F. Chatelain, Low-pressure powder injection molding using an innovative injection press concept, The International Journal of Advanced Manufacturing Technology, (2017) 1-11.