Experimental and theoretical methods for optimal solids loading calculation in MIM feedstocks fabricated from powders with different particle characteristics

Abstract

To cite this article: J. M. Contreras, A. Jiménez-Morales & J. M. Torralba (2010) Experimental and theoretical methods for optimal solids loading calculation in MIM feedstocks fabricated from powders with different particle characteristics, Powder Metallurgy, 53:1, 34-40 To link to this article: http://dx.The aim of this work is to investigate the influence of the particle characteristics of powder to the mixing stage of the powder injection moulding process to identify the best procedure with which to evaluate the optimal solids loading for feedstock fabrication. To perform the present study, powder blends that are made from three bronze and four Inconel 718 powders, with different particle size distributions and morphologies, are mixed with a binder system that is based on polyethylene and wax. Powder-binder blends are prepared by varying the powder content to study how the powder characteristics affect the optimal solids loading. In addition, a new method is presented for determining the optimal solids loading in powder injection moulding feedstocks through the activation energy calculation of powder-binder blends that are prepared with different powder contents. This novel method is compared with the optimal loading values that have been determined by other ways as torque rheometry, determination of the tap-real density ratio and through rheological models.

Torque rheology of zircon feedstocks for powder injection moulding

“…They have also been demonstrated to be quite useful for determining the optimal and critical solid loadings for a feedstock. 4,5 In a torque rheometer, the torque exerted by gyratory rotors to displace a bulk of a fluidised mass is measured as a function of the time to create a plot of torque vs. time, called a rheogram. The torque is related to the fluid viscosity and can thus serve as a measure of the resistance of a fluid to deformation by either shear or tensile stress.…”

Powder Injection Moulding - An Alternative Processing Method for Automotive Items

“…Hausnerova et al (2009), employed another approach to determine temperature sensitivity of PIM compounds and reached the same conclusion. Very recently, Contreras et al (2010) broaden this finding for a set of three bronze and four Inconel 718 powders. According to their observation, activation energy diminishes with increasing powder content up to the optimum powder loading of the particular compound, while for feedstocks exceeding optimum loading, the activation energy becomes enhanced.…”

Development of Hypereutectic AlSi Alloy Powder Injection Molding Feedstocks by Rheological Analysis

“…Figure 6 presents the evolution of rheological parameters, n, B, and E with variations of the binder content at reference conditions of 150°C and 1000 s −1 . From Figure 6, the typical zone of the critical binder content can be estimated [30,31]. A region of signi cant changes in all rheological parameters occurred at 16-18 wt.% binder content.…”