Design of Shock Absorber Housing Using Aluminum Vacuum Die Casting Technology

진철규,강충길 한국산업융합학회 2018 한국산업융합학회 논문집 Vol.21 No.1

The purpose of this study is to develop a high-strength, high-toughness, thin-walled aluminum shock absorber housing product by applying a high vacuum die casting method to improve internal gas defect and formability. The analysis program dedicated for the casting was used because it was too costly and time-consuming to adopt the gating system design. The final casting plan was designed based on the flow pattern of the material filled into the mold and the result of air pressure and air pocket after the material was completely filled in the mold. Gaty shape was designed as a split type. The runner was designed to have the same shape as the initial inlet curve of the cavity, and the flow of the molten metal was prevented from turbulent flow. The most favorable results were obtained when the injection speed was V2 = 4.0 m/s. Defects on pores were reduced by applying high vacuum level inside the mold.

Effect of rubber forming process parameters on channel depth of metallic bipolar plates

진철규 한국산업융합학회 2017 한국산업융합학회 논문집 Vol.20 No.3

In this study, bipolar plates in fuel cells are formed using rubber forming process. The effects of important parameters in rubber forming such as hardness and thickness of rubber pad, speed and pressure of punch that compress blank, and physical property of materials on the channel depth were analyzed. In the soft material sheet Al1050, deeper channels are formed than in materials STS304 and Ti-G5. Formed channel depth was increased when hardness of rubber pad was lower, thickness of rubber pad was high, and speed and pressure of punch were high. It was found the deepest channel was achieved when forming process condition was set with punch speed and pressure at 30 mm/s and 55 MPa, respectively using rubber pad having hardness Shore A 20 and thickness 60 mm. The channel depths of bipolar plates formed with Al1050, STS304 and Ti-G5 under the above process condition were 0.453, 0.307, and 0.270 mm, respectively. There were no defects such as wrinkle, distortion, and crack found from formed bipolar plates.

터보 팬의 유동해석 및 허니콤 구조가 적용된 터보 팬의 PBF 3D 프린팅 제작에 관한 연구

진철규,이해수,이운길,우재혁,Jin, Chul-Kyu,Lee, Haesoo,Lee, Un-Gil,Woo, Jae-Hyeog 한국산업융합학회 2022 한국산업융합학회 논문집 Vol.25 No.5

In this study, a study was conducted to localize a large aluminum turbo fan used for tank powerpack. The turbo fan was scanned with a 3D scanner and then 3D modeling was performed. Computational fluid dynamics (CFD) were performed from the performance conditions of the fan, and structural analysis was performed using the pressure data obtained from CFD. The fan was reduced to 1/5 size by applying the geometric similarity. A 1/5 size fan has a honeycomb structure inserted into the front shroud and back shroud to reduce the weight by 5.3%. A 1/5 size fan was printed using a PBF 3D printer, and a 1/5 size fan with honeycombs was also printed. The pressure drop of 8.67 kPa and the required power of 138.19 kW, which satisfies the performance conditions of the fan, were confirmed from the results of CFD. The values of the maximum deformation amount of 0.000788 mm and the maximum effective stress of 0.241 MPa were confirmed from the structural analysis results. The fan printed by the PBF 3D printer had the same shape as the modeling, and the shape was perfect. There are no defects anywhere in appearance. However, the condition of the outer surface of the fan's back shroud is rough compared to other locations. The fan in which the honeycomb was inserted was also perfectly output, and the shape of the honeycomb was the same as the modeling.

Die design optimization of die casting for fabrication of fuel cell aluminum bipolar plate with micro-channel through casting simulation and experimental investigation

진철규,Chan Hyun Jang,강충길 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.10

In vacuum die casting, we require a high quality die design for fuel cell bipolar plates to prevent unfilled phenomena, turbulent flow,and porosity. We have designed a die for thin plate die casting using two geometric shapes. In addition, we propose a new overflow system based on numerical simulation, and conducted actual vacuum die casting experiments. An optimal die design consists of seven overflows at the end of the cavity and three overflows at each side wall of the cavity. In our experiment, the molten metal that passed the gate and reached the side wall flowed into the side overflow, no turbulent flow occurred, and the filling behavior and are uniform. In addition,partially solidified molten metal passing through the channel was perfectly eliminated by overflow without back-flow. To validate the proposed approach, a good quality sample was manufactured using the optimal die design with the proposed overflow system.

A Study on the Remanufacturing for Drive Spur Gear in Planner Miller by Directed Energy Deposition

진철규,김민우,우재혁 한국산업융합학회 2022 한국산업융합학회 논문집 Vol.25 No.6

In this study, additive manufacturing technology was applied to restore a planner miller that was unusable due to aging. The drive spur gear of the planner miller was inoperable due to many defects in the teeth. The shape of the defective gear teeth was restored by deposition of the defective teeth using the DED method. However, as the location of the deposition head and the location of the set origin became farther, the deposition shape was different from the modeling shape. Nonetheless, since the modeling of the deposition part was designed to be larger than the tooth shape of the original gear, it was possible to completely restore all gear teeth through post-processing. The arrangement interval of the flow lines of the deposition part was narrower than that of the substrate. The hardness of the substrate was 172 HV, and that of the deposition part was 345 HV, which was twice as high as that of the substrate.

Studies on the Forming Process for the Bipolar Plate of Fuel Cells

진철규,이준경 한국산업융합학회 2018 한국산업융합학회 논문집 Vol.21 No.4

Stamping process and rubber pad forming process were performed to manufacture the bipolar plate for fuel cells. For that, a vacuum die casting process and a semi-solid forming process wherein liquid-state materials were used were adopted. After preparing the blank with the stainless steel thin plate having a thickness of 0.1 mm, the bipolar plate channel was formed with the stamping process and rubber pad forming process. The depth of the bipolar plate channel prepared by the stamping method was 0.45 mm and the depth of the bipolar plate channel prepared by the rubber pad forming process was 0.41 mm. Meanwhile, with the vacuum die casting and semi solid forming, the bipolar plate having a channel depth of 0.3 mm, same as the size of the die, could be formed.

A Comparative Study on the Formability of Aluminum Bipolar Plate with Channels using Indirect Squeeze Casting and Stamping

진철규,강충길 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

In this study, a fuel cell bipolar plate is formed using indirect squeeze casting which uses liquid materials and stamping process which uses solid state materials. The formability of these two types of processes is discussed. The shapes of die cavity in the indirect squeeze casting and that in the stamping are same. The materials filling rate during indirect squeeze casting was increased as punch pressure that pushes molten aluminum into cavity of die is increased. A breakage occurs when load of upper die which presses aluminum plate 0.1mm thick is at 20 kN. When load of upper die is at 15 kN, the maximum channel depth is achieved. Though precise channel shape can be achieved by the indirect squeeze casting, the thickness of bipolar plate is larger by around three times than that formed by stamping. An irregular-shaped channel is obtained in the bipolar plate formed by stamping due to problems of wrinkle, springback, and flatness. The current density of unit cell with casted aluminum bipolar plate with TiN layer and stamped aluminum bipolar plate are 421 and 410 mA cm-2 at 0.6 V, respectively

전차 파워팩에 적용되는 알루미늄 터보 팬의 주조방안 설계 및 주조 해석에 관한 연구

진철규,이운길,Jin, Chul-Kyu,Lee, Un-Gil 한국산업융합학회 2022 한국산업융합학회 논문집 Vol.25 No.5

In this study, sand casting process was applied to manufacture a large aluminum turbo-type fan used for tank powerpack. To apply the sand casting method, the turbo fan was reverse engineered, and after designing three gating systems, the optimal gating system design was selected by performing casting simulation. In the case of the bottom up-gating system, there is a significant temperature loss of the molten alloy during blade filling. When the molten alloy is completely filled into the sand mold, the blade upper tip and front shroud are below the liquidus temperature. In the case of the top down-gating system, molten alloy scattering occurs, but the temperature loss while the blade is filled is smaller than that of the bottom up type. And after the inflow of molten alloy into the mold is completed, the blade upper tip and front shroud are higher than the liquidus temperature. A sand mold was manufactured with the top down-gating system and the casting process was performed. The fan was made perfectly in appearance without any unfilled parts.

잠수함 마스트 커버의 주조방안설계 및 주조해석

진철규 한국산업융합학회 2023 한국산업융합학회 논문집 Vol.26 No.5

In this study, the sand casting process was applied to design the gating system and perform casting simulation in order to domestically produce the submarine mast cover. Based on simulation results, casting experiments were conducted to produce a soundness prototype. The design concept of the mast cover's gating system was based on the design of bell casting. By arranging eight tower-type gates in a circle at 45° intervals, the flow of melt flowing into each gate was uniform and did not mix with each other, and the velocity of melt was also uniform. The mast cover made of Ni-Al-Bronze alloy has no unfilled parts. However, small porosities and flow marks occurred on the surface in several places. Yield strength and ultimate tensile strength are 279.3 MPa and 675.7 MPa, respectively, and elongation is 21.2%.

Design of the Spur Gear with Honeycomb Lattice Structure and PBF Printing

진철규 한국산업융합학회 2023 한국산업융합학회 논문집 Vol.26 No.4

In this study, the spur gear with honeycomb lattice structures are designed. The pitch diameter and body length of the spur gear are Ø93 mm and 104.0 mm, respectively. The designed gear was printed using Powder bed fusion (PBF) 3D printer. The gear is 3D printed perfectly. Even the teeth and honeycombs of the gear were output in the same way as the design shape. The printed gear with honeycomb lattice structure has a 24% smaller cross-sectional area and 29% smaller volume and weight than conventional solid structure gears. The surface roughness is approximately 4.5 μm, and the hardness is 345 HV.