Preparation of Aluminum Feedstock for Green Part Specimen Using Metal Injection Molding

2013 ◽  
Vol 465-466 ◽  
pp. 1250-1254 ◽  
Author(s):  
Hafeiz Saidin ◽  
M. Azuddin
Keyword(s):  
Injection Molding ◽  
Paraffin Wax ◽  
Metal Injection Molding ◽  
Sudden Increase ◽  
Binder System ◽  
Molding Machine ◽  
Metal Composition ◽  
Binder Composition ◽  
Wax Content ◽  
Process Ability

In metal injection molding, to identify the homogenous aluminum based feedstock is a challenging issues. In this study, a metal injection molding of aluminum feedstock which contains of high density polyethylene, stearic acid and paraffin wax as binder system was performed. The feedstock are used to produce tensile and gear shape green specimens using injection molding machine. The process ability of the metal injection molding feedstock depends on different parameters such as their binder composition and amount of metal powder used. From this study, the percentage of volume shrinkage experienced a sudden increase at the metal composition more than 50%. It also shown that, the paraffin wax content, affects the feedstock performances.

The Characterization and Flow Behavior of 316L Stainless Steel Feedstock for Micro Metal Injection Molding (μMIM)

2010 ◽  
Vol 44-47 ◽  
pp. 2872-2876
Author(s):  
Pei Li Haw ◽  
Norhamidi Muhamad ◽  
Hadi Murthadha
Keyword(s):  
Stainless Steel ◽  
Injection Molding ◽  
316L Stainless Steel ◽  
Flow Behavior ◽  
Palm Stearin ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Binder System ◽  
Molding Process ◽  
Rheological Characterization

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.

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

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.

Effects of Binders System on Sintered Properties of Metal Injection Molding Parts of M2 High Speed Steel

2014 ◽  
Vol 1024 ◽  
pp. 201-204 ◽  
Author(s):  
Rosliza Sauti ◽  
Nor‘aini Wahab ◽  
Mohd Afian Omar ◽  
I.N. Ahmad
Keyword(s):  
Injection Molding ◽  
High Speed ◽  
High Speed Steel ◽  
Palm Stearin ◽  
Steel Powder ◽  
Paraffin Wax ◽  
Metal Injection Molding ◽  
Waste Rubber ◽  
Vacuum Atmosphere ◽  
M2 High Speed Steel

This paper reports on the compatibility of waste rubber binder combined with conventional binder, paraffin wax and local binder, palm stearin for M2 High Speed Steel injection molding in order to obtain the better properties. The feedstock was prepared at a powder loading of 65 vol.% using 22um M2 High Speed Steel powder and the binders consisting of 55wt.% paraffin wax/palm stearin, 21wt.% polyethylene, 14wt.% waste rubber and 10wt.% stearic acid. The specimens were then sintered in vacuum atmosphere within a temperature range from 1200°C to 1260°C. The results shown even the best properties is obtain from the conventional binders, paraffin wax, thus the properties of local binders palm stearin is still comparable and good. The maximum density of paraffin wax binder was 8.095g/cm3 achieved at temperature 1250°C and palm stearin binder was 8.111g/cm3 achieved at temperature 1240°C. Therefore, in term the best strength of paraffin wax was 2351Mpa whilst palm stearin was 2210MPa, both recorded at temperature 1230°C.

Novel Binder System Based on Paraffin-Wax for Low-Pressure Injection Molding of Metall–Ceramic Powder Mixtures

2001 ◽  
Vol 3 (12) ◽  
pp. 995 ◽  
Author(s):  
M. Leverkoehne ◽  
J. Coronel-Hernandez ◽  
R. Dirscherl ◽  
I. Gorlov ◽  
R. Janssen ◽  
...  
Keyword(s):  
Injection Molding ◽  
Ceramic Powder ◽  
Low Pressure ◽  
Paraffin Wax ◽  
Binder System ◽  
Powder Mixtures ◽  
Pressure Injection

Rheological Properties of Copper-Graphite MIM Feedstocks Prepared with Waste PET Binder

2014 ◽  
Vol 660 ◽  
pp. 209-213 ◽  
Author(s):  
Mohammad Fadhil Mat Nor ◽  
Safian Sharif ◽  
Khairur Rijal Jamaludin
Keyword(s):  
Shear Rate ◽  
Injection Molding ◽  
Rheological Properties ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Binder System ◽  
Molding Process ◽  
Capillary Rheometry

In this study, waste polyethylene terephthalate (PET) polymer binder systems were used to prepare copper-graphite metal injection molding (MIM) feedstock. A mixer and screw extrusion were used to achieve optimized feedstock, and the rheological properties of the resulting fluids were evaluated using a capillary rheometry to simulate the injection molding process. The solid loadings in the copper-graphite mixes were investigated in the ranges of 51-53% using PET binder system. The effects of shear rate (γ), solid volume fraction (φ) and temperature (T) on the rheological behavior of the copper/graphite MIM feedstocks are discussed.High viscosity trend was notably recorded as shear rate increased relatively. The results indicated that this feedstock system shows dilatant characteristic and lots of further work shall be conducted in attempt to establish this as an ideal binder system.

Segregation Measurement of Inconel 718 Feedstocks Used in Low-Pressure Metal Injection Molding

2016 ◽  
Vol 857 ◽  
pp. 286-290 ◽  
Author(s):  
Faoud Fareh ◽  
V. Demers ◽  
S. Turenne ◽  
O. Scalzo
Keyword(s):  
Injection Molding ◽  
Inconel 718 ◽  
Volume Fraction ◽  
Phase Segregation ◽  
Ethylene Vinyl Acetate ◽  
Low Pressure ◽  
Paraffin Wax ◽  
Metal Injection Molding ◽  
Solid Loading ◽  
Molten State

Low-pressure metal injection molding (LP-MIM) is an advanced manufacturing technology where a wax-based feedstock is injected into a complex shape before densification heat treatments. Feedstock is generally designed to minimize segregation, maximize flowability, maximize the strength of the molded component, maximize the solid loading potential and ease of debinding. In this study, the emphasis is placed on the evaluation of the effect of segregation on different wax-based Inconel 718 superalloy feedstocks used in LP-MIM. In powder metallurgy, particle or phase segregation generates a fluctuation of the particle distribution in powder-binder mixtures from point to point. Such demixing generally occurs before or during the injection process, and can lead to the formation of defects such as cracks, distortions or heterogeneous shrinkage of the sintered parts. Different wax-based feedstocks were poured in cylindrical hot molds (95°C), maintained in molten state for 1 minutes or for 60 minutes, and rapidly cooled to room temperature. The specimens were then extracted from the top and bottom regions of each cylindrical part. A thermogravimetric analysis technique was used to measure the volume fraction of powder at these two locations in order to quantify the degree of segregation in green parts. The best candidate feedstocks minimizing segregation are the mixtures containing only paraffin wax, or those containing paraffin wax and ethylene vinyl acetate combined. An increase in the time spent in the molten state and the use of beeswax or stearic acid promote the powder-binder separation of feedstocks.

Mixing and Characterisation of Stainless Steel 316L Feedstock for Waste Polystyrene Binder System in Metal Injection Molding (MIM)

2014 ◽  
Vol 607 ◽  
pp. 83-86 ◽  
Author(s):  
Rosli Asmawi ◽  
Mohd Halim Irwan Ibrahim ◽  
Azriszul Mohd Amin
Keyword(s):  
Stainless Steel ◽  
Injection Molding ◽  
Palm Kernel ◽  
Steel Powder ◽  
Metal Injection Molding ◽  
Binder System ◽  
Stainless Steel 316L ◽  
Palm Kernel Oil ◽  
Kernel Oil ◽  
Waste Polystyrene

This paper describes the mixing process and homogeneity analysis of a newly developed binder system based on waste polystyrene (PS) and palm kernel oil (PKO) to produce feedstock for metal injection molding (MIM). Since mixing is a critical step in MIM process, hence the mixture of powder and binder should be homogeneous and injectable. In this study, water atomised Stainless Steel powder was mixed with a new binder system consisting of waste polystyrene and palm kernel oil in a Brabender Plastograph EC rotary mixer. Several tests were performed to assess the homogeneity of the feedstock that was produced at 60 vol.% powder loadings. The 60 vol.% was chosen because the Critical Powder Volume Concentration (CPVC) of the SS316L powder was found to be 64.8 vol.%. The tests conducted were density, binder burn-out and SEM morphology observation. It was found that the feedstock shows good homogeneity and suitable for further processing in MIM.

Investigations on Metal Injection Molding of 316L SS Using Thermoplastic Natural Rubber (TPNR) Binder as a New System

2012 ◽  
Vol 576 ◽  
pp. 150-153 ◽  
Author(s):  
Hassan Norita ◽  
Noor Azlina Hassan ◽  
Sahrim H. Ahmad ◽  
N. Muhamad ◽  
Mohd Afian Omar ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
Injection Molding ◽  
Natural Rubber ◽  
Extraction Process ◽  
Metal Injection Molding ◽  
Binder System ◽  
Outward Appearance ◽  
Injection Parameter ◽  
Near Net Shape ◽  
Thermoplastic Natural Rubber

Metal injection molding (MIM) is a near net-shape manufacturing technology that is capable of mass production of complex parts cost-effectively. The unique features of the process make it an attractive route for the fabrication of the new binder system since the success of MIM process is dependent on the outward appearance of the resultant feedstock. Thermoplastic natural rubbers (TPNR) blends consist of thermoplastics, such as polyethylene (PE), alloyed with natural rubber (NR) with different thermoplastic to NR ratios. The soft grade TPNR is produced by blends with compositions richer in rubber while the harder grades can contain up to about 30 % NR. This study investigates the influence of new binder system consisting of TPNR on injection parameter, density of injected molded specimen and changes during solvent extraction. Results show that TPNR plays an important role as a good binder system and shortens the solvent extraction process.

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