Metal injection molding (MIM) is a novel process classified in powder metallurgy. This process can produce complex metallic parts with high rate of production and consists of four stages, including mixing, injection, debinding, and sintering, where the properties of the final part highly depends on the parameters of each of these stages. In this study, the parameters of injection pressure, injection and mold temperature, holding pressure, holding time, injection speed, and cooling time on the density, strength, and hardness of the final MIM compact have been investigated. By the design of experiments and response surface methodology (RSM) method, 50 samples have been injected using different parameters. In order to measure the density, tensile strength, ad hardness of the samples, the debinding and sintering procedures have been done on the injected samples. The results show that the injection pressure, injection temperature, and mold temperature have the highest effect on the strength and density of the final part, respectively, and on the other hand, holding pressure, holding time, and cooling time have a negligible effect. Within the measured properties, density and strength are more affected by the injection parameters compared to hardness. Finally, the optimum injection parameters for samples made of 4605 low alloy steel include injection pressure of 133 bar, injection temperature of 158oC, mold temperature of 60oC, the holding pressure of 70 bar, holding time of 8 second, injection speed of 112 mm/min, and cooling cycle of 17 second.

Metals and polymers are frequent materials for engineering purposes. Technological advances have called for new materials with high stiffness and low production cost, especially in automotive industry.Up until now, the most common approach has been to employ high strength metals like steel in manufacturing different parts and subsequently coating them with regard to their application, in order to reach maximum performance. One of the novel composites is metal-polymer hybrid which is produced by injection molding a layer of polymer on a laser cladded metal to form a laminated composite. The superiority of this method lies in the diversity of pattern and powder materials and feed rate in cladding that can be optimized for a particular loading in different applications. Evaluating parameters are holding pressure, mold temperature, cladding pattern, and polymer thickness. Simple Tension and threepoint bending tests showed that the maximum strength of joint adhesion was achieved at 50℃ mold temperature, lower holding pressure (70MPa), higher thickness (3mm), and parallel pattern. Moreover, better flexural modulus was reached at 50oC mold temperature, lower holding pressure (70MPa), lower thickness (2mm), and parallel pattern.

In the present study, the effective parameters of injection stage of the metal injection molding process (MIM) is investigated in order to make a sound industrial part from the AISI-4605 low-alloy steel. In order to design of experiments and also to optimize different parameters of injection, statistical method of response surface method (RSM) and five-variable Box-Behnken Design (BBD) have been used assuming a quadratic model. Using this software, 46 experiments were designed. Then the samples are made and their density is measured. After that, the importance of the injection parameters as well as the interaction between each parameter have been investigated using analysis of variance (ANOVA). Finally, this research has shown that the injection temperature of 155°C, the injection speed of 80 mm/s, the holding pressure of 83 bar, the holding time of 9 seconds and the injection pressure of 132 bar led to the maximum density of the green body, which is equivalent to 4.892 g/cm2. Finally, after producing a new sample using the optimal parameters a piece with a density of 4.9 g/cm2 was obtained, and it was observed that the results were very close to the predicted value, which presented the model has good accuracy in prediction.

The most important steps in the metal injection molding (MIM) process are the design and manufacture of the injection mold. By far the most influential factors in the quality of the part are the injection site in the mold and how the part is filled during the injection molding, which directly affects the quality of the final part. In this paper, a powder containing 316L stainless steel is used as the raw material, and the Moldex 3D software is used for the simulations. The injection time, the cooling time, and the keeping time parameters are considered fixed for all tests with the values of 2. 5, 10, and 2 seconds respectively. The speed, pressure, and temperature of injection are also considered as effective parameters. The boundary layer method (BLM) is used to simulate the process. The 3D model of the part is designed with three gate paths and different injection conditions. The injection mold is made for the optimized sample and produced under different conditions. Comparing the results of simulations with the experimental results shows the accuracy of the simulation results. The results also show that in the process of MIM, the injection fluid has a very high viscosity and different behavior compared to the similar fluid of the base polymer used in the feed. Besides, the optimal values for speed, pressure, and temperature of injection are found to be 60%, 60%, and 185 °,C, respectively.

This paper compares the shrinkage of the components manufactured by injection molding, using inserts made of epoxy resin and metal alloys with low melting point (LMPA). For this purpose, in first stage, two cube molds (inserts) manufactured by epoxy resin and a low melting point alloy (150MCP). At the using an injection machine, two types of polymers, (polyethylene and polystyrene) were injected into the inserts. Then exact dimensions of the injected components, plus shrinkage caused by inserts materials, (epoxy resin and metal alloys with low melting point) were measured. Also, the effect of injection parameters on shrinkage of the components, investigated, these parameters include injection pressure, holding time and temperature of the polymer melt. The results indicate a reduction in shrinkage in components of polyethylene, which is made in LMPA insert. Reduction in length and width and height are 62.0, 46.0 and 75.0 respectively. Polystyrene components made by both inserts, have about the same percentage of the shrinkage. Increasing the injection pressure and holding time, significantly reduced the shrinkage of components in both inserts.

Extrusion, injection molding, calendaring, and thermoforming are just a few of the processing techniques utilized in the plastics industry. Gas-assist injection molding plays a crucial role in this equipment. The advancement of standard injection molding is represented by this apparatus. Parts with thin wall thickness and hollow sections can be manufactured using this method. Use this strategy to save between 30% and 35% of the material. In this procedure, gas is first introduced after a brief shot of material is injected. The remaining portion of the cavity is filled in by injecting gas. The hollow section is described in detail by the gas core. In gas-assist injection molding, the geometry of the gas channel design is also very important. There is a wide variety of materials available for polymeric applications. Different polyamide materials, including polypropylene, polycarbonate, high-impact polystyrene, and polyethylene terephthalate (PET), can be processed using gas-assisted injection molding. Talc-filled polypropylene has been chosen for this study's simulation and experimental work. For simulation purposes, Moldflow plastic insight is utilized. Moldflow plastic insight was used to simulate the tensile samples, and gas-assist injection molding was used to create the experimental models. Simulation and experimental results are used to measure the wall thickness and gas penetration depth. The validation was then checked by comparing these results.

Product quality for plastic injection molding process is highly related with the settings for its process parameters. Additionally, the product quality is not simply based on a single quality index, but multiple interrelated quality indices. To find the settings for the process parameters such that the multiple quality indices can be simultaneously optimized is becoming a research issue and is now known as finding the efficient frontier of the process parameters. This study considers three quality indices in the plastic injection molding: war page, shrinkage, and volumetric shrinkage at ejection. A digital camera thin cover is taken as an investigation example to show the method of finding the efficient frontier. Solidworks and Moldflow are utilized to create the part’s geometry and to simulate the injection molding process, respectively. Nine process parameters are considered in this research: injection time, injection pressure, packing time, packing pressure, cooling time, cooling temperature, mold open time, melt temperature, and mold temperature. Taguchi's orthogonal array L27 is applied to run the experiments, and analysis of variance is then used to find the significant process factors with the significant level 0.05. In the example case, four process factors are found significant. The four significant factors are further used to generate 34 experiments by complete experimental design. Each of the experiments is run in Moldflow. The collected experimental data with three quality indices and four process factors are further used to generate three multiple regression equations for the three quality indices, respectively. Then, the three multiple regression equations are applied to generate 1,225 theoretical datasets. Finally, data envelopment analysis is adopted to find the efficient frontier of the 1,225 theoretical datasets. The found datasets on the efficient frontier are with the optimal quality. The process parameters of the efficient frontier are further validated by Moldflow. This study demonstrates that the developed procedure has proved a useful optimization procedure that can be applied in practice to the injection molding process.

The one forming method in powder engineering is the injection molding method of metal powders. The combination of conventional molding methods in plastic injection and using metal powders has led to significant improvements in the quality of production of sensitive and complex parts in various industries. In this method, the metal powder is mixed with a set of polymeric materials and an injectable mass is formed, which is called feedstock. The resulting feedstock is injected by metal injection machines and the binder part is removed. The de-adhesive part is subjected to a sintering process by controlled atmosphere furnaces to increase its strength and mechanical properties. In this research, first, the optimal binder composition for the production of industrial parts is created. In this research de-binding of a polymeric component at low temperatures is applied to reduce the total production costs of synthesis and after injection of the properties of the final part was discussed. The most important feature of industrial binder composition in the production of various parts is its high ability to remove quickly and without creating cracks and blisters in the final part, while the components of the optimal binder must be available and show good sintering behavior. Based on the results, a four-component binder based on polyethylene oxide has been synthesized, while reducing the final price of the parts, it has been removed well during the solvent and thermal descaling process and its slow release rate during cracking have prevented cracks and blisters in the final parts.