Effects of Metal Powder Characteristics on the Compactibility and Sinterability in Micro Metal Injection Molding Process

The rheological behaviors of the Micro Metal Injection Molding feedstock are important for the stability of the feedstock during micro injection molding process and quality of the final micro-components. Homogeneous feedstocks are preferable for MIM process to ensure the dimensional consistency of molded components and prevent the defects of powder-binder separation or particle segregation. In this work, feedstocks with various formulations of 316L stainless steel and binder system were prepared by using Brabender Plastograph EC Plus mixer. The binder system comprises of palm stearin, polyethelene (PE) and stearic acid. In order to obtain the viscosity, activation energy, flow behavior and mold ability index, the rheological characterization of the feedstocks were investigated in numerous conditions by using Shimadzu 500-D capillary rheometer The study showed that all of the 316L stainless steel feedstocks are homogenous with pseudo-plastic behaviors.

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Study on Stability of a Novel Binder System Based on Palm Stearin in Metal Injection Moulding Application

Scientific Research Journal ◽

10.24191/srj.v4i2.5655 ◽

2007 ◽

Vol 4 (2) ◽

pp. 1

Author(s):

Muhammad Hussain Ismail ◽

Norhamidi Muhamad ◽

Aidah Jumahat ◽

Istikamah Subuki ◽

Mohd Afian Omar

Keyword(s):

Injection Molding ◽

Flow Characteristics ◽

Injection Pressure ◽

Palm Stearin ◽

Steel Powder ◽

Metal Injection Molding ◽

Injection Molding Process ◽

Binder System ◽

Molding Process ◽

Flow Activation Energy

Metal Injection Molding (MIM) is a wellestablished technology for manufacturing a variety of complex and small precision parts. In this paper, fundamental rheological characteristics of MIM feedstock using palm stearin are theoretically analyzed and presented. The feedstock consisted of gas atomized 316L stainless steel powder at three different particle size distributions and the binder system of palm stearin (PS) and polyethylene (PE). The powder loading used was 60vol % for all samples (monosize 16 µm, monosize 45 µm, and bimodal 16 µm + 45 µm) and the binder system of 40vol %(PS/PE = 40/60). The viscosity of MIM feedstock at different temperatures and shear rates was measured and evaluated. Results showed that, the feedstock containing palm stearin exhibited suitable rheological properties by increasing the fluidity of feedstock in MIM process. The rheological results also showed a pseudoplastic flow characteristics, which poses higher value of shear sensitivity (n) and lower value of flow activation energy (E), that are both favourable for injection molding process. The green parts were successfully injected and exhibited adequate strength for handling by optimizing the injection pressure and temperature.

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Manufacturing and High Temperature Mechanical Properties of Inconel 713C by Using Metal Injection Molding

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.602-604.627 ◽

2012 ◽

Vol 602-604 ◽

pp. 627-630 ◽

Cited By ~ 1

Author(s):

Kyu Sik Kim ◽

Kee Ahn Lee ◽

Jong Ha Kim ◽

Si Woo Park ◽

Kyu Sang Cho

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Injection Molding ◽

Room Temperature ◽

Tensile Tests ◽

Metal Injection Molding ◽

Injection Molding Process ◽

Molding Process ◽

High Temperature Mechanical Properties ◽

Inconel 713C

Inconel 713C alloy was tried to manufacture by using MIM(Metal Injection Molding) process. The high-temperature mechanical properties of MIMed Inconel 713C were also investigated. Processing defects such as pores and binders could be observed near the surface. Tensile tests were conducted from room temperature to 900°C. The result of tensile tests showed that this alloy had similar or somewhat higher strengths (YS: 734 MPa, UTS: 968 MPa, elongation: 7.16 % at room temperature) from RT to 700°C than those of conventional Inconel 713C alloys. Above 800°C, however, ultimate tensile strength decreased rapidly with increasing temperature (lower than casted Inconel 713C). Based on the observation of fractography, initial crack was found to have started near the surface defects and propagated rapidly. The superior mechanical properties of MIMed Inconel 713C could be obtained by optimizing the MIM process parameters.

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