• Design & Manufacturing
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• 제15권1호
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• pp.21-25
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• 2021

When the product is removed from the mold after molding during the sheet metal molding process, elastic recovery causes a springback phenomenon. Much research has been done to minimize this phenomenon. In this study, V-bending experiments were conducted using galvanized steel sheets, stainless steel, and aluminum sheet materials, using a total of nine types of thin sheet materials of 1.0t, 1.5t, and 2.0t, respectively. Molding analysis and experimental data were compared and analyzed. In the case of galvanized steel sheets, it was considered that the springback phenomenon occurs more frequently in molding analysis than in experiments. It was considered that the springback phenomenon occurs greatly in the experiment, not the interpretation of the molding of the stainless steel plate and the aluminum plate. It was considered that the springback occurrence tendency of the molding analysis and the experiment was the same, and the springback occurrence error rate of the molding analysis and the experimental result was about 4.0%.

• 한국정밀공학회지
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• 제32권11호
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• pp.969-976
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• 2015

In the present study, a numerical investigation of an insert injection molding process was carried out for the development of thermoplastic microfluidic chip plates with metal electrodes. Insert injection molding technology enables efficient realization of a plastic-metal hybrid structure and various efforts have been undertaken to produce novel components in several application fields. The microfluidic chip with metal inserts was proposed as a representative example and its molding process was analyzed. The important characteristics of the filling stage, such as the effects of filling time and thickness of the part cavity, were characterized. Furthermore, the detailed distributions of pressure and temperature at the end of the filling stage were investigated, revealing the significance of metal insert temperature.

• Design & Manufacturing
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• 제14권4호
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• pp.71-77
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• 2020

Various manufacturing technologies, including over-molding and insert-injection molding, are used to produce hybrid plastics and metals. However, there are disadvantages to these technologies, as they require several steps in manufacturing and are limited to what can be reasonably achieved within the complexities of part geometry. This study aims to determine a practical approach for producing metal/plastic hybrid components by combining plastic injection molding and metal die casting to create a new hybrid metal/plastic molding process. The integrated metal/plastic hybrid injection molding process developed in this study uses the proven method of multi-component technology as a basis to combine plastic injection molding with metal die casting into one integrated process. In this study, the electrical conductivity and ampacity were verified to qualify the new process for the production of parts used in electronic devices. The electrical conductivity was measured, contacting both sides of the test sample with constant pressure, and the resistivity was measured using a micro ohmmeter. Also, the specific conductivity was subsequently calculated from the resistivity and contact surface of the conductor path. The ampacity defines the maximum amount of current a conductive path can carry before sustaining immediate or progressive deterioration. The manufactured hybrid multi-components were loaded with increasing currents, while the temperature was recorded with an infrared camera. To compare the measured infrared images, an electro-thermal simulation was conducted using commercial CAE software to predict the maximum temperature of the power loaded parts. Overall, during the injection molding process, it was demonstrated that multifunctional parts can be produced for electric and electronic applications.

• Design & Manufacturing
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• 제16권4호
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• pp.24-33
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• 2022

Fiber-reinforced plastics(FRPs) have excellent specific stiffness and strength, so they are usually used as automotive parts that require high rigidity and lightweight instead of metal. However, it is difficult to predict the mechanical properties of injection molded parts due to the fiber orientation and breakage of FRPs. In this paper, the fiber orientation characteristics and mechanical properties of injection molded specimens were evaluated in order to fabricate automotive transmission side covers with FRPs and design a rib structure for improvement of their rigidity. The test molds were designed and manufactured to confirm the fiber orientation characteristics of each position of the injection molded standard plate-shaped specimens, and the tensile properties of the specimens were evaluated according to the injection molding conditions and directions of specimens. A gusset-rib structure was designed to improve the additional structural rigidity of the target products, and a proper rib structure was selected through the flexural tests of the rib-structured specimens. Based on the evaluation of fiber orientation and mechanical characteristics, the optimization analyses of gate location were performed to minimize the warpage of target products. Also, the deformation analyses against the internal pressure of target product were performed to confirm the rigidity improvement by gusset-rib structure. As a result, it could be confirmed that the deformation was reduced by 27~37% compared to the previous model, when the gusset-rib structure was applied to the joining part of the target products.

• Design & Manufacturing
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• 제17권3호
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• pp.55-60
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• 2023

The fiber-reinforced plastics and cellular injection molding process can be used to efficiently reduce the weight of battery housing components of mild hybrid electronic vehicles(MHEV) made of metal. However, the fiber orientation of fiber-reinforced plastics and the growth of foaming cells are intertwined during the injection molding process, so it is difficult to predict the mechanical properties of products in the design process. Therefore, it is necessary to evaluate the mechanical properties of the materials prior to the efficient stiffness design of the target product. In this study, a study was conducted to evaluated the mechanical properties of fiber reinforced cellular injection-molded specimens. Two types of fiber-reinforced plastics that can be used in the target product were evaluated for changes in tensile properties of cellular injection-molded specimens depending on the foaming ratio and position from the injection gate. The PP and PA66 specimens showed a decrease of tensile modulus and strength of approximately 30% and 17% depending on the foaming ratio, respectively. Also, the tensile strength decreased approximately 26% and 17% depending on the position from the injection gate, respectively. As a result, it was confirmed that the PP specimens have a significantly mechanical property degradation compared to the PA66 specimens depending on the foaming ratio and position.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.211-212
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• 2006

Production components fabricated by metal powder injection molding are analyzed for features to identify the design window for this powder technology. This reverse approach lets the designer see where PIM has a high probability to succeed. The findings show that the most suitable components tend to be less than 25 mm in size and less than 10 g in mass, are slender, and have high complexity.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.93-94
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• 2006

A novel production method for porous metal components has been developed by applying powder space holder (PSH) method to metal powder injection molding (MIM) process. The PSH-MIM method has an industrial competitive advantage that is capable of net-shape manufacturing the micro-sized porous metal products with complicated shapes and controlled porosity and pore size. In this study, the small impeller with homogeneous micro-porous structure was manufactured by the PSH-MIM method. The effects of combinations in size and fraction of PMMA particle on dimensional tolerance and variation of sintered porous specimens were investigated. It was concluded that the PSH-MIM method could manufacture commercially microporous metal components with high dimensional accuracy.

• 한국주조공학회지
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• 제27권1호
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• pp.42-47
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• 2007

Vacuum molding process(V-process) has several benefits such as a lower total production cost and a high quality casting comparing to the conventional sand molding. Influence of the gating design on the molten metal flow was investigated in this study. General criteria for the gating design of the castings and commercial codes for the flow and solidification analysis were used to attain the optimized gating design in V-process. Though mold cavity was filled smoothly under the low initial velocity of molten metal, molten metal dashed against the upper part of the mold before the completion of the mold filling with higher initial molten metal velocity and fell soon. This phenomenon may affect collapsing the mold shape, however it is thought that the possibility of burning out of the vinyl by the molten metal is not so high because vinyl is coated with refractory material.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.57-61
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• 2009

In recently industry, with the miniaturization and high-precision of machine part, the development of mold manufacturing technology for mass production is accompanied by the development of new industrial field such as IT, NT and BT. The metal injection molding(MIM) process combines the well-known thermoplastic injection and powder metallurgy technologies to manufacture small parts for IT, NT, BT industrial. In this study, the bar type MIM mold with a 800um thickness is made for influence of feedstock material and injection parameter through an experiment.

• 한국기계가공학회지
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• 제14권2호
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• pp.87-92
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• 2015

The injection molding process is widely used in the production of most plastic products. In order to make metal-colored plastic products like those found in modern luxury home alliances, metallic pigments are mixed with a basic resin material for injection molding. However, process control for metal-colored plastic products is extremely difficult due to the non-uniform melt flow of the metallic resin pigments. In this study, the effect of process parameters on the quality of a metal-colored plastic product is evaluated. A rapid mold cooling method using a compressed cryogenic fluid is also proposed to decrease the content of undesired compounds within the plastic product.