Metal Injection Molding Research Articles

PENGGUNAAN MATERIAL 316L UNTUK GREEN-PART TEST PIECE DENGAN TEKNIK METAL INJECTION MOLDING

Material 316L is one type of iron with excellence corrosion resistant and was used in many industries. 316L is used as feed stock material for Green-part test piece which is a product of the Metal Injection Molding (MIM) process. The study showed, the manufacture of green part made from standard 316L material has been carried out. Green part is a product made by injection mold stage from MIM process. The stages of research carried out refer to the Metal Injection Molding process with the standard references that included three stages carried out which are the preparation of feedstock, mold design, and mold testing with the injection process by testing material and by the 316L feedstock. The purpose of this study is to analyze the green part test piece that was made with 316L material in MIM process with a specific measurement and the quality of the end product using tensile test. Results of this study indicate that the right parameters was achieved to produce shapes that match the targeted geometry of the 316L feed stock material. The tensile strength test show reading of 110Mpa but when compared with other studies, the value was still under standard.

Recent Advances in Processing of Titanium and Titanium Alloys through Metal Injection Molding for Biomedical Applications: 2013-2022.

Metal injection molding (MIM) is one of the most widely used manufacturing processes worldwide as it is a cost-effective way of producing a variety of dental and orthopedic implants, surgical instruments, and other important biomedical products. Titanium (Ti) and Ti alloys are popular modern metallic materials that have revamped the biomedical sector as they have superior biocompatibility, excellent corrosion resistance, and high static and fatigue strength. This paper systematically reviews the MIM process parameters that extant studies have used to produce Ti and Ti alloy components between 2013 and 2022 for the medical industry. Moreover, the effect of sintering temperature on the mechanical properties of the MIM-processed sintered components has been reviewed and discussed. It is concluded that by appropriately selecting and implementing the processing parameters at different stages of the MIM process, defect-free Ti and Ti alloy-based biomedical components can be produced. Therefore, this present study could greatly benefit future studies that examine using MIM to develop products for biomedical applications.

Effect of Temperature, Holding Time, and Addition of Sn on Density on Metal Injection Molding Sintering Process

Metal injection molding (MIM) is a metal forming technique that combines powder metallurgy with plastic injection molding. MIM is very efficient in manufacturing small and complex products in large quantities. The MIM process has four steps: mixing, debinding, injection molding, and sintering. This research was conducted to determine the effect of variations in Sn addition, temperature, and holding time on the density of Al-PP products after the sintering process. Density is mass per volume so to find out the volume of Al-PP products, the use of a 3D scanner was attempted along with the EinScan application and a mesh mixer. The Taguchi method was used for data processing to determine the influence of variations in Sn addition, temperature, and holding time on density. The calculation of the percentage contribution showed that variations in Sn addition, temperature, and holding time affected density by 47%, 21%, and 3%. Also, 2% Sn addition yielded a reasonably good microstructure formation compared to without Sn addition and 1% Sn addition, where many voids remained in the specimen (the more significant the voids, the lower the density).

Effect of Mo Additions on the Physical, Mechanical and Corrosion Properties of Commercially Pure Ti Fabricated by Metal Injection Moulding

Effect of Mo Additions on the Physical, Mechanical and Corrosion Properties of Commercially Pure Ti Fabricated by Metal Injection Moulding

Study of microstructure and mechanical properties of 17-4 PH stainless steel produced via Binder Jetting

ABSTRACT The microstructure and mechanical properties of 17-4 stainless steel produced by Binder Jetting (BJT) and heat treated according to the standard conditions for the 17-4 PH steel (H900 and H1100) were investigated. The sintered relative density is 97.8% with a slightly anisotropic shrinkage. Tensile strength and elongation are above the minimum required for the wrought steel and comparable to those of the same material manufactured by Metal Injection Molding. They are also better than those reported in the literature for the 17-4 PH stainless steel manufactured by BJT. Tensile elongation at fracture is anisotropic, highlighting a significant dependence of the non-uniform plastic deformation on the direction.

Interactions of polymeric components in a POM-based binder system for titanium metal injection moulding feedstocks

ABSTRACT Owing to the different characteristics of each of the multiple polymers, obtaining a homogenous metal injection moulding (MIM) feedstock blend is challenging. Therefore, studying interactions between the polymeric components is vital for achieving suitable MIM feedstocks. We report on the effects of different compatibilisers – EGMA and E40 – on the interactions in polyoxymethylene (POM) and polypropylene (PP) blends. We measured contact angles and performed Fourier transform infrared spectroscopy and atomic force microscopy analyses to identify the suitable compatibiliser that yields a feedstock with excellent properties. It was found that the binder system based on EGMA-3 demonstrates the lowest contact angle and best miscibility for the POM/PP blends compared to E40. This enhanced interaction lies in the chemistry of EGMA, having an active site that reduces the interfacial tension between the components of the POM/PP blend. Subsequently, this creates a positive interaction between the polymers and metal powders, ensuring good adhesion within the feedstock.

Characterization of Green Part of Steel from Metal Injection Molding: An Analysis Using Moldflow

Metal injection molding (MIM) is a quick manufacturing method that produces elaborate and complex items accurately and repeatably. The success of MIM is highly impacted by green part characteristics. This work characterized the green part of steel produced using MIM from feedstock with a powder/binder ratio of 93:7. Several parameters were used, such as dual gates position, injection temperature of ~150 °C, and injection pressure of ~180 MPa. Analysis using Moldflow revealed that the aformentioned parameters were expected to produce a green part with decent value of confidence to fill. However, particular regions exhibited high pressure drop and low-quality prediction, which may lead to the formation of defects. Scanning electron microscopy, as well as three-dimensional examination using X-ray computed tomography, revealed that only small amounts of pores were formed, and critical defects such as crack, surface wrinkle, and binder separation were absent. Hardness analysis revealed that the green part exhibited decent homogeneity. Therefore, the observed results could be useful to establish guidelines for MIM of steel in order to obtain a high quality green part.

Overview of MIM Technology Development in the Last 25 Years through Our μ-MIM Technology

It was a great honour for us to receive the 59th technical achievement award of Japan Society of Powder and Powder metallurgy (JSPM). We presented an overview of the metal injection moulding (MIM) technology development over 25 years of experience and future trends through our originally developed μ-MIM technology in the annual spring meeting of JSPM 2022, which are summarised in this paper.The μ-MIM technology is developed for especially small size metal parts with strict dimensional tolerances. We have focused only on a small complex designed metal part production in a net shaping, thus, the trend related to MIM parts larger than 50 mm in size is not covered. We have also joined the Micro Manufacturing Association in Japan since its establishment in 2018, which promotes micro parts manufacturing technology to the world. The demand increment of micro parts in various industries is never slowdown thus our μ-MIM technology overview might be instructive for both powder metallurgy and micro parts manufacturing interests.

Mechanical Properties and Deformation Behavior of Metal Injection Molded Products with Cellulose Nanofiber

Metal Injection Molding (MIM) process is suitable for fabricating small and complex shaped metal parts with high production volume. In this study, in order to improve the MIM process, cellulose nanofibers (CNF) were focused. There are problems such as deformation during debinding and sintering due to the addition of a large amount of binder. On the other hand, the strength of the green compact decreased with decreasing binder contents. In this study, cellulose nanofibers were added with a binder during mixing in order to improve the handling of green compacts, and decrease the deformation during debinding and sintering. The effects of CNF contents on the mechanical properties were investigated. It was clarified that CNF is effective in improving the handleability of the debound compacts and suppressing deformation during sintering.

Fe-Cr-Si and Fe-Cr-Si-Mo Soft Magnetic Alloys Produced by MIM Process

In recent years, metal injection molding (MIM) has been adopted as a manufacturing method for solenoid valves which are parts of electronic fuel injectors, and PB permalloy parts have been commercialized. However, Ni, a constituent element of PB permalloy, is an expensive material, making it difficult to produce fuel injector parts at low cost. To solve this problem, the use of inexpensive Fe-Cr alloys has been considered. However, its properties are insufficient as a material for solenoid valves, which require improved magnetic properties, reduced core loss, and improved corrosion resistance, and these requirements have been increasing year by year. As a solution to this problem, we studied magnetic and material properties of Fe-Cr-Si and Fe-Cr-Si-Mo alloys produced by MIM process. These results revealed that magnetic properties were improved by reducing the amount of Cr, and that corrosion resistance was improved by adding Mo even if the amount of Cr was reduced. In this review, we describe the magnetic and material properties of Fe-Cr-Si and Fe-Cr-Si-Mo alloys produced by MIM process.

Effect of Sintering Temperature and Solution Treatment on Phase Changes and Mechanical Properties of High-Nitrogen Stainless Steel Prepared by MIM

High-nitrogen stainless steel (HNSS) has been widely concerned and studied owing to its excellent mechanical, corrosion resistance, and biocompatibility properties. A series of HNSS was prepared by metal injection molding (MIM) using gas atomized Fe-Cr-Mn-Mo-0.3 N duplex stainless steel powders. Both sintering and solution treatments were carried out in an N2 atmosphere. The effects of nitrogen distribution and phase transformation on the mechanical properties of MIM HNSS during sintering and solution were studied. The results show that as the sintering temperature increased, the sample density increased, but the total nitrogen content decreased. Nitrogen and Cr2N concentration gradients along the cross-section of as-sintered samples were formed after cooling. The high nitrogen content promotes the decomposition of γ: γsaturated translated to γ and Cr2N. Meanwhile, the low Mn content in austenite also decomposes γ: γ translated to α and Cr2N. After solution treatment, a single γ phase was obtained for samples sintered at 1200 to 1320 °C. For solution treatment samples sintered at 1320 and 1350 °C, their tensile strength was 988.76 and 1036.12 MPa; yield strength was 615.61 and 636.14 MPa, and elongation was 42.58 and 40.08%, respectively. These values vastly exceeded the published MIM HNSS values.

Sintering optimization of high nitrogen nickel free austenitic stainless steel prepared by Metal Injection Molding

High nitrogen and nickel free austenitic (HNNFA) stainless steel prepared by powder metallurgy has become a research hotspot because of solving nickel precipitation and saving cost. In this paper, metal injection molding (MIM)method was used to prepare such kinds of steel. The effect of sintering parameters such as sintering temperature, holding time, and nitriding pressure on the density, shrinkage rate, and nitrogen content of austenitic stainless steel was systematically evaluated by an orthogonal experiment to obtain the optimum sintering parameters. When the sintering temperature is 1200°C, the holding time is 6 h, and the nitriding pressure is 1100 mbar, the sample possesses a higher density (7.52g/cm3) and nitrogen content (0.76%). The matrix of stainless steel is austenite after nitriding sintering.

Antimicrobial activity of porous metal injection molded (MIM) 316L stainless steel by Zn, Cu and Ag electrodeposition

Porous 316L stainless steel samples were functionalized with electrodeposited zinc, copper, and silver coatings for antimicrobial activity against gram-positive bacteria Staphylococcus aureus (S. aureus). Porous stainless steel samples were created by combining metal injection molding (MIM) with a powder space holder (PSH) technique using sodium chloride (20 wt%) as a space holder material. Galvanostatic (0.10 A) electrodeposition was used for zinc, copper, and silver deposition, and antimicrobial activity of functionalized samples was evaluated using a touch test protocol with S. aureus. All electrodeposited samples completely prevented the growth of S. aureus. These results confirm that metal depositions only in the pores of the porous 316L were sufficient to inhibit the growth of S. aureus completely.

Fabrication of Equiatomic CoCrFeMnNi High-Entropy Alloy by Metal Injection Molding Process Using Coarse-Sized Powders

Fabrication of Equiatomic CoCrFeMnNi High-Entropy Alloy by Metal Injection Molding Process Using Coarse-Sized Powders

Tensile and axial fatigue properties of AISI 316 L stainless steel fabricated by materials extrusion additive manufacturing

Herein, the surface quality, physical, microstructural, tensile and axial fatigue properties of 316 L stainless steel fabricated by materials extrusion additive manufacturing (MEX) are investigated and compared to the well-established and similar fabrication process, metal injection moulding (MIM). The results reveal no discernible difference in microstructure, preferential orientation and grain size between MEX and MIM parts, except for voids between deposited paths found in MEX parts, and Si-O inclusions in MIM parts. MEX parts have slightly higher tensile properties than MIM parts due to the higher relative sintered density. However, the endurance limit of MEX parts is lower than MIM. This is attributed to differences in the surface characteristics, in which MEX parts have layer-by-layer characteristics, higher roughness and Al2O3 contamination from the separator. They sensitively act as crack origination sites and result in lower fatigue resistance when compared to MIM.

Effects of Carbon Content on the Properties of Novel Nitrogen-Free Austenitic Stainless Steel with High Hardness Prepared via Metal Injection Molding

A novel nitrogen-free austenitic stainless steel with a hardness of >200 HV was developed using metal injection molding (MIM), and the effects of graphite addition on the sintering behavior, mechanical properties, and corrosion resistance of heat-treated samples were investigated. The results show that a certain amount of graphite addition increases the relative density to >98%. In samples with the addition of 0–500 ppm graphite, large grain-boundary precipitates reduced corrosion resistance and ductility. In contrast, when graphite addition was increased to 750–1500 ppm, fine precipitates, which exhibited coherent lattice relationships with the matrix, were uniformly distributed within the grain and grain boundaries; this significantly improved the mechanical properties and corrosion resistance. The tensile strength and elongation intervals were 546.94–608.62 MPa and 29.68–24.63%, respectively. To prevent overburning, samples with a graphite content higher than 3000 ppm were sintered at a lower temperature, resulting in a higher porosity and lower performance.

Binder jet green parts microstructure: advanced quantitative analysis

3D binder jet technology has drawn significant attention in recent years thanks to its ability to build complex shapes with a wide variety of commercial powders, together with the advantage of not using high energy sources during the printing process. Binder jet makes use of several printheads containing a formulated binder to build the layers of a part within a few seconds. This allows a significant improvement of the manufacturing productivity and quality with respect to laser powder bed fusion (LPBF) or conventional metal injection molding (MIM).Current scientific and industrial investigations in binder jet are focused on the relationship between the printing parameters, the macroscopic properties, and the microstructures of sintered parts. However, there is a knowledge gap related to the relationship between the process parameters and the microstructure and properties of green parts.In this work, a novel green microstructural analysis methodology, based on scanning electron microscopy (SEM) and X-ray computed tomography (XCT), is presented. SEM microstructural observations are supported by machine learning pixel-wise classification algorithms that enables image analysis. This new method facilitates the definition of green parts' key process metrics and the description of consolidation mechanisms (layer consolidation, powder bed interactions) under different printing conditions, before sintering. Thus, the binder and porosity distributions in green microstructures can be correlated to green and sintered macroscopic properties, such as sintered density, with a final modelling and prediction objective for process acceleration. The proposed novel and robust methodology is applied to particular empirical cases.

Metal injection molding of high-performance Ti composite using hydride-dehydride (HDH) powder

Aiming at solving the interstitial oxygen contamination for titanium (Ti) parts fabricated by metal injection molding (MIM) technology, we innovatively introduced LaB6 oxygen scavenger to eliminate its adverse effect and produce a high-performance Ti material using inexpensive hydride-dehydride (HDH) Ti powders. Rheological behavior of feedstocks, decomposition behavior of binders, as-sintered microstructure and mechanical properties were systematically studied. The viscosity of feedstock F2 containing LaB6 powder meets the requirement of injection molding operation. The as-sintered 0.5 wt% LaB6/Ti composite has homogenous and fine microstructure with the average grain size of 65.6 μm. The in-situ TiB and oxygen-containing (La2O3 and La-Cl-O) reinforcements are formed by the reaction of LaB6 and Ti matrix, which are uniformly distributed in the composite. The generated TiC particle and Ti matrix exist an orientation relation of (111¯)TiC||(011¯0)Ti and [101]TiC||[0001¯]Ti. The LaB6/Ti composite possesses excellent mechanical properties, with the ultimate tensile strength of 632 MPa, yield strength of 548 MPa and elongation of 15 %. Attributed to the oxygen scavenger of LaB6, the elongation of the composite is greatly increased by 163 % compared with pure Ti. This work provides a valuable guidance for the development of low-cost and high-performance Ti parts by MIM technology.

How titanium MIM parts are made

Praxis Powder Technology, a US company that makes titanium components for a range of industries including medical and aerospace, explains the metal injection molding (MIM) process when using titanium powder.

Influence of Sintering Atmosphere, Temperature and the Solution-Annealing Treatment on the Properties of Precipitation-Hardening Sintered 17-4 PH Stainless Steel.

So far, unlike metal injection molding (MIM), conventional powder metallurgy technology (PM) has not been regarded as a method for producing structural elements from 17-4 PH powders, due to the problems of obtaining almost fully compacted shapes after sintering. Nevertheless, recent research demonstrates that it is possible to manufacture sintered parts with high strength by pressing and sintering. The purpose of the study was to determine the degree of densification of 17-4 PH sintered stainless steel during sintering at different temperatures and atmospheres. As a result of the study, it was pointed out that both the temperature and the sintering atmosphere play an essential role in the process of densification of the studied powders during sintering. The formation of delta ferrite and a more pronounced degree of spheroidization of the pores is activated by a higher sintering temperature. Furthermore, after solution-annealed and age-hardened treatment, sintered 17-4 PH stainless steel exhibits high strength with moderate ductility at a level that is difficult to achieve for other sintered stainless-steel grades, such as austenitic, ferritic and martensitic. In turn, the largest improvement in the pitting corrosion resistance in 0.5 M NaCl solution is reached by sintering at 1340 °C in hydrogen and after solid solution treatment.