• Design & Manufacturing
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• v.6 no.2
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• pp.54-58
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• 2012

A counter shaft gear is an important part in the transmission system of vehicle. Its shape is relatively complicated and should meets high strength. Traditionally it has been manufactured as follows; the counter shaft gear has consisted of a clutch and helical body with teeth which are forged and machined for teeth respectively and then attached by frictional welding. In this study, a new hot forging process was proposed and designed so that the counter shaft gear is formed as one body without divide it into two parts. Furthermore, the precision forging process has been developed for the clutch teeth without additional grinding.

• Design & Manufacturing
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• v.12 no.2
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• pp.5-10
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• 2018

Vacuum-assisted thermoforming is one of the critical steps for successful application of film insert molding(FIM) to parts of complex shape. In this study, the simulations and experiments of thermoforming processes were performed to investigate the effects of process conditions on thickness distribution and printed pattern deformation of films in vacuum-assisted thermoforming. The film thickness uniformity increased with decreasing film heating time, whereas it increased with increasing vacuum delay time. After thermoforming of films with uniform pattern space of 5mm, the maximum space was 9.432mm. Based on the simulation, a modified pattern was calculated to obtain uniform spaces after thermoforming. In the experiments for film with the modified pattern, the maximum space appeared 5.837mm. In, addition. the predicted patterns were in good agreement with the experimental results.

• Design & Manufacturing
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• v.13 no.1
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• pp.13-18
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• 2019

The size and prospects of the domestic semiconductor equipment market are increasing every year. In the case of various parts used inside semiconductor equipments, high durability such as high strength and abrasion resistance is demanded. Particularly, the gases used in semiconductor production processes are toxic. In order to prevent such toxic gas leakage, a precision processing technique and a surface treatment technique for preventing corrosion are required. Electro-polishing is an electro-chemical method of polishing a metal surface to make it smooth and polished. Electro-polishing is mainly used in the finishing process of metal surface. Unlike mechanical polishing, electro-polishing is used in many fields, such as fine chemical etching equipment, since no damaged layer or burr, fine polishing groove and particles are generated. However, in order to withstand the gas used in the semiconductor equipment, the parts must have high corrosion resistance. However, the surface hardness generally become lowered through electro-polishing. Therefore, in this study, surface hardness were experimentally observed before and after electro-polishing. Then, a method of improving hardness by preparing a nitrided layer by plasma ion nitriding treatment.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.6
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• pp.142-151
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• 2013

This study develops an automation system for metallic mold design that is applicable in forging non-axial symmetric parts. The metallic mold design program is used to design the metallic mold using two-dimensional axial symmetric metallic molds and to predict the stress concentration using finite element analyses. Then, the program redesigns the metallic mold using variables such as the optimal split diameter, maximum allowable inner pressure, fit tolerance, and stress distribution, which are calculated using the metallic mold design program. When the involute spur gear is forged, stress concentration occurs on the tooth root bounded at the symmetric surface. The SCM4 material is suitable for metallic molds because the stress is less than the yield strength of the insert and it acts on the tooth root regardless of the inner pressure. The metallic mold for forging non-axial symmetric parts can be designed through adjusting the magnitude of the contact pressure. The program developed in this study can be applied to metallic mold designs in involute spur gears of forging, which is an ordinary non-axial symmetric part.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.4
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• pp.47-53
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• 2007

A bearing is one of core parts in automobile. Rubber seal of the bearing is important to improve performance of bearing, formed by hot-press die of rubber seal for the intricate shape. In this study, formed tools are used to machine die of bearing rubber seal and the machining operation is classified into the several process of high precision. Design of experiments is used to optimize selection of the formed tools for the efficient machining of the hot-press die. The cutting force, tool wear and tool life are determined to characteristics. And, the clearance angle, the rake angle and the length cutting edge are considered as the major factors. Experiments are repeated to use one-way factorial design, and tool life is predicted by regression model.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.180-183
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• 2006

The contraction rate is a very important element that dominate quality of product in plastic injection molding. To get wanted products, the contraction rate of used resin must be considered necessarily when designing plastic injection molds, and suitable deform conditions must be chosen with this. In this paper, important parts used in LED department were produced by injection mold using POM resin, and dimension error that happened by contraction rate of resin was corrected and reflected in die design and suitable deform conditions were decided.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.1
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• pp.1-7
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• 2019

In the modern industrial period, the introduction of mass production was most important progress in civilization. Die-casting process is one of main methods for mass production in the modern industry. The aluminum die-casting in the mold filling process is very complicated where flow momentum is the high velocity of the liquid metal. Actually, it is almost impossible in complex parts exactly to figure the mold filling performance out with the experimental knowledge. The aluminum die-castings are important processes in the automotive industry to produce the lightweight automobile bodies. Due to this condition, the simulation is going to be more critical role in the design procedure. Simulation can give the best solution of a casting system and also enhance the casting quality. The cost and time savings of the casting layout design are the most advantage of Computer Aided Engineering (CAE). Generally, the relations of casting conditions such as injection system, gate system, and cooling system should be considered when designing the casting layout. Due to the various relative matters of the above conditions, product defects such as defect extent and location are significantly difference. In this research by using the simulation software (AnyCasting), CAE simulation was conducted with three layout designs to find out the best alternative for the casting layout design of an automotive Oil Pan_BJ3E. In order to apply the simulation results into the production die-casting mold, they were analyzed and compared carefully. Internal porosities which are caused by air entrapments during the filling process were predicted and also the results of three models were compared with the modifications of the gate system and overflows. Internal porosities which are occurred during the solidification process are predicted with the solidification analysis. And also the results of the modified gate system are compared.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.482-489
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• 2020

This study conducted a prototype development and evaluation by performing die-casting mold design, mold manufacturing, and injection condition optimization based on flow and solidification analysis to meet the needs of the coupling parts produced by die casting. Through flow analysis, the injection conditions suitable for 100% filling in the cavity were found to be a molten metal temperature of 670 ℃, injection speed of 1.164 m/s, and filling pressure of 6.324~18.77 MPa. In addition, solidification close to 100 % occurred in all four cavities when the solidification rate was 69.47 %. A defect inspection on the surface and inside the product revealed defects, such as poor molding and pores. In addition, the dimensions of the injected product were within the target tolerance and showed good results. Through the feedback of the results of flow and solidification analysis, it was possible to optimize the mold design, and the injection optimization conditions were confirmed to be a total cycle time of approximately 6.5 seconds. Good quality carrier parts with an average surface hardness of approximately 45 mm from the gate measured at 97.48(Hv) could be produced.

• Design & Manufacturing
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• v.8 no.2
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• pp.18-22
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• 2014

Two shot molding is one of the injection method which uses two materials or two color materials simultaneously in one mold. Two shot molding is good rate of productivity and economical because of no extra-progress necessary. The cowl grille is located in the bottom of wind shield glass and rolls as a passage of air inlet to inside of vehicle. It consists of body and seal. Firstly, the body is injected with PP. Next seal is extruded with EPDM and engineered and then assembled with body. These procedures lead high cost of production and the quality of part has problems. Therefore, it has effects on saving production cost and being a solution of the quality problems with the development of two shot molding cowl grille. It is guaranteed that two shot molding will be widely used in the vehicle parts industry afterwards.

• Design & Manufacturing
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• v.14 no.1
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• pp.15-21
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• 2020

Smart systems in different application areas such as automotive, medical and consumer electronics require a novel manufacturing method of electronic, optical and mechanical functions into products. Traditional methods including mechanical assembly, bonding of plastic and electronic circuit cause the problems in large size of products and complicated manufacturing processes. In this study, thermoforming and film insert molding were applied to fabricate a dome shaped plastic part embedded with electronic circuits. The deformation of patterns printed on PET film was predicted by thermoforming simulation using T-SIM, and the results were compared with those by experiment. In order to decrease spring-back after thermoforming, the Taguchi method of design of experiment was used. Through ANOVA analysis, it was found that mold temperature was the most dominant parameter for spring-back. By using flow analysis, gate design was performed to decrease injection pressure. During film insert molding, the wash-out of ink printed on film occurred for Polycarbonate. When the resin was changed to PMMA, the wash-out disappeared due to low melt temperature.