Impact of binder constituents on the moldability of titanium-based feedstocks used in low-pressure powder injection molding

• Published in: Powder technology Vol. 381; pp. 255 - 268
• Main Authors: Côté, Raphaël, Azzouni, Mohamed, Demers, Vincent
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.03.2021; Elsevier BV
• Subjects: Acetic acid; Binder; Constituents; Ethylene vinyl acetates; Feedstock; Injection; Injection molding; Low pressure; Metal injection molding; Mold filling; Moldability; Numerical simulation; Paraffin; Paraffin wax; Powder; Powder injection molding; Raw materials; Spherical powders; Stearic acid; Titanium; Titanium powder; Vinyl acetate; Viscosity; Viscosity; Binder; Metal injection molding; Numerical simulation; Feedstock; Mold filling; Titanium powder
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2020.12.008

This work presents an experimental and numerical approach to study the impact of binder constituents and solid loading on spherical titanium powder-based feedstocks used in low-pressure powder injection molding. The viscosity profiles of 35 feedstocks were used to quantify the threshold proportions of each constituent. The binder which maximizes the moldability and demolding while minimizing the segregation is constituted of 1, 1 and 3 vol% of stearic acid, ethylene-vinyl acetate and carnauba wax, respectively, and paraffin wax making up the balance. The maximum solid loading capable of producing intricate parts with minimal defects was found to be 64 vol%. Finally, numerical simulations were carried out along with experimental validation to study the injection flow in an intricate mold cavity. Results show that numerical simulations are in good agreement with experimental values in predicting the melt front position during injection of high solid loading feedstock in complex shape cavity. [Display omitted] •1 vol% of stearic acid in a titanium-based feedstock decrease the viscosity.•3 vol% of carnauba in a titanium-based feedstock improve the demolding.•Ti-based LPIM feedstock was numerically simulated in a complex mold cavity.•Melt front shape and injection time were accurately predicted.