Study on Binder System for Micro Powder Injection Molding of ZrO₂ Ceramic

Abstract:

Micro powder injection molding has been accepted as a potential forming technology for large-scale production of miniature components in industries. However, mold filling capability is often poor due to the blind hole structure of the die cavity, which restricts the widespread application of this technique. In this paper, ZrO₂ micro gears with addendum circle ranging from 900μm to 200μm were studied. Instead of using traditional PW-HDPE-SA binder as in powder injection molding, thermoplastic binder system is optimized here for better replication of micro gear. It is found that the dimensional accuracy and demold after injection molding can be improved by utilizing proper binder system. ZrO₂ feedstock with a powder loading of 46vol.% and the binder system consisting of BW, HDPE and SA was successfully injection molded and demolded, which indicates good mold filling capability and sufficient demolding strength. The binder system was successfully removed by debinding process in two steps, solvent debinding followed by thermal debinding. Debound components free of defects were obtained. Keywords: Micro powder injection molding, ZrO₂ feedstock, Binder system, Molding filling capability, Demolding strength

• Periodical: Materials Science Forum (Volumes 706-709)
• Pages: 1948-1954
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.706-709.1948
• Online since: January 2012
• Authors: Lin Liu, X.L. Ni, Hai Qing Yin, Xuan Hui Qu
• Keywords: Binder System, Demolding Strength, Micro Powder Injection Molding, Molding Filling Capability, ZrO₂ Feedstock

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