scholarly journals The Technological Design of Geometrically Complex Ti-6Al-4V Parts by Metal Injection Molding

2019 ◽  
Vol 9 (7) ◽  
pp. 1339 ◽  
Author(s):  
Shulong Ye ◽  
Wei Mo ◽  
Yonghu Lv ◽  
Zhanhua Wang ◽  
Chi Tat Kwok ◽  
...  
Keyword(s):  
Injection Molding ◽  
Cost Effective ◽  
Metal Injection Molding ◽  
Binder System ◽  
Prealloyed Powder ◽  
Low Viscosity ◽  
Blended Powder ◽  
Complex Shapes ◽  
Thermal Debinding ◽  
Decomposition Behavior

In this study, the metal injection molding (MIM) process is applied to produce Ti-6Al-4V parts using blended and prealloyed powders, respectively. The feedstocks are prepared from a polyformaldehyde-based binder system with a powder loading of 60 vol%, exhibiting a low viscosity. The decomposition behavior of the binders is investigated and the thermal debinding procedure is designed accordingly. The debound parts are subsequently sintered at 1200 and 1300 °C. The results show the mechanical properties of the sintered samples prepared from blended powder are comparable to those prepared from prealloyed powder, with yield strength of 810 MPa, ultimate tensile strength (UTS) of 927 MPa, and elongation of 4.6%. The density of the as-sintered samples can reach 4.26 g/cm3 while oxygen content is ~0.3%. Based on the results, watch cases with complex shapes are successfully produced from Ti-6Al-4V blended powder. The case gives a good example of applying metal injection molding to mass production of precise Ti-6Al-4V parts with complex shapes in a cost-effective way.

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.

Thermal Debinding Process of SS 17-4 PH in Metal Injection Molding Process with Variation of Heating Rates, Temperatures, and Holding Times

2017 ◽  
Vol 266 ◽  
pp. 238-244 ◽  
Author(s):  
Sugeng Supriadi ◽  
Bambang Suharno ◽  
Rizki Hidayatullah ◽  
Gerra Maulana ◽  
Eung Ryul Baek
Keyword(s):  
Injection Molding ◽  
Heating Rate ◽  
Crack Formation ◽  
Holding Time ◽  
Effect Of Temperature ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Mass Reduction ◽  
Thermal Debinding ◽  
Debinding Process

Generally, metal injection molding (MIM) method utilizes SS 17-4 PH as material for application of orthodontic bracket. One of the process of MIM is thermal debinding, which binder is eliminated by thermal energy. In this study, thermal debinding process is conducted with variation of temperature, i.e. 480, 510, and 540°C, holding time, i.e. 0.5, 1 and 2 hours, heating rate, i.e. 0.5, 1, 1.5, and 2°C/min.The effect of temperature shows that the increased temperature will result in the mass reduction percentage due to formation of oxide on the sample, which will be proven through TGA testing. The highest mass reduction was 6.4137 wt% which was obtained at 480°C. For the variation of holding time, the longer the holding time will result in increased mass reduction and the highest mas reduction was 6.255 wt% which was obtained during 2 hours of holding time. For the heating rate, the slower the heating rate will result in increased mass reduction and decreased the presence of crack formation. The best variable was obtained at heating rate of 0.5°C/min, which resulted mass reduction of 6.2488 wt% and less crack formation.

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.

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.

Processing of the Fe3Si Alloy from Prealloyed Powder Fe45Si by Metal Injection Molding

2008 ◽  
Vol 591-593 ◽  
pp. 86-90
Author(s):  
Doublas José da Silva ◽  
Aline Silva ◽  
Ricardo Machado ◽  
Paulo A.P. Wendhausen
Keyword(s):  
Chemical Composition ◽  
Injection Molding ◽  
Complex Geometry ◽  
Raw Materials ◽  
Metal Injection Molding ◽  
Vacuum Furnace ◽  
Prealloyed Powder ◽  
Dimensional Precision ◽  
Maximum Permeability ◽  
Better Than

The known process as Metal Injection Molding is derived from the conventional powder metallurgy (M/P) being an alternative for production of parts with complex geometry, great dimensional precision and freedom of chemical composition. The present work has the objective to evaluate the processing of the Fe3Si alloy sintering in the vacuum furnace using as raw materials iron powder carbonyl and prealloyed powder Fe45Si with D90<10-m. Properties of microhardness, density, coercivity, magnetic permeability, and chemical composition was evaluated. The obtained results were compared with what is presented in the literature for parts processed by conventional ways and with parts processed by M/P. A density of 7,620 kg/m3, a coercive field (Hc) of 101.14 A/m, a relative maximum permeability of 5,484 and a residual induction of 1.1 T was achieved by MIM. Comparing with conventional processes (where 100% of densification is reached), the MIM process results were worse, however they were better than P/M.

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.

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