• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.86-92
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• 2021

Usually, the die-cast components used in small mobile devices require finishing processes, such as computer numerically controlled coating. In such cases, porosity is the most important defect. The shape of the molten aluminum that passes through the runner and gate in a mold is the one of the factors that influences gas porosity. To define the spurt index, which numerically indicates the shape of molten aluminum after the gate, Reynolds number and Ohnesorge number are used. Before die fabrication, computer-aided engineering analysis is performed to optimize the filling pattern. Finally, X-ray and surface inspection are performed after casting and machining to evaluate how the spurt index affects porosity and other product parameters. Based on the results obtained herein, a new gating system design process is suggested.

• Design & Manufacturing
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• v.14 no.4
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• pp.58-64
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• 2020

Lately, the development of the semiconductor industry has led to the miniaturization of electronic devices. Therefore, semiconductor wafers of very thin thickness that can be used in Multi-Chip Packages are required. There is active research on the backgrinding process to reduce the thickness of the wafer. The backgrinding process polishes the backside of the wafer, reducing the thickness of the wafer to tens of ㎛. The equipment that performs the backgrinding process requires ultra-precision. Currently, there is no full auto backgrinding equipment in Korea. Therefore, in this study, ultra-precision backgrinding equipment was designed. In addition, finite element analysis was conducted to verify the equipment design validity. The deflection and structural stability of the backgrinding equipment were analyzed using finite element analysis.

• Design & Manufacturing
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• v.17 no.2
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• pp.1-8
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• 2023

This study aims to enhance the price and quality competitiveness of imported tiles by developing a robotic tile production automation line. The development process involved several steps, such as requirement analysis, derivation of technical specifications, conceptual design, engineering feasibility review, detailed design, and production. Emphasis was placed on the transfer process of the tiles' molds, and technological advancements were achieved through engineering interpretation, feasibility review, and performance evaluation. The developed automation system incorporates key specifications to ensure a transfer success rate of over 90%, thereby ensuring stable transportation of the tiles and minimizing defect rates during production. The maximum weight capacity for tile pick-up was set above 6 kg, allowing effective handling of tiles weighing 6 kg or less in automated tasks. Furthermore, the system enables safe and precise movement of the tiles to the desired location, with a transfer distance of at least 1.3 m and a transfer speed exceeding 0.2 m/sec, thereby increasing production efficiency.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.10
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• pp.3142-3151
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• 1996

As plastics shrink when changing from a molten to a solid state, mold cavities must by made larger than the product specification, In making molded gears, the teeth in the cavity must be carefully compensated for shrinkage so that the teeth of gears will have the correct profile. Two compensation methods are widely used in the cavity design. One is the compensation of a module and the other is the modification of a pressure angle and profile shifting coefficient. These methods, however, do not provide a gear cavity with all disign parameters for gears and several parameters are determined by experience. In this paper, the new design technique, namely the compensation method of design parameters, was proposed , which is based on the three kinds of shrinkage rates obtained from the measuring data of the prototype of molded gears. Using the shrinkage rates in the tip circle, tooth heigth and tooth thickness, we calculate the whole design parameters of a gear cavity. Thus, the gear cavity is considered as a complete gear with the compensated module, pressure angle, profile shifting coefficient, clearance coefficient and back lash amount so that the formula of gears can be applied to the cavity design effectively. Experimental results show that more precision molded gears can be made by using the proposed design method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.310-315
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• 2017

Automotive waterproof connectors are highly functional parts that must be air-tight in a complex environment. In the LSR multi-cavity injection molding process for manufacturing waterproof connectors, it is important to maintain a uniform curing temperature between the cavities in order to obtain a quality product. For this purpose, we designed the capacity of the cartridge heater differently for each position, and then linked the heat transfer analysis and optimization module to obtain the optimal cartridge heater capacity. As a result of the optimization analysis, the temperature deviation between cavities was decreased from $13.1^{\circ}C$ to $8.1^{\circ}C$ compared with the case in which constant heater capacity was applied, so that the design criterion could be satisfied within a temperature deviation of $10^{\circ}C$ for uniform curing. This study suggests that this method can be applied efficiently to the design of a large area multi-cavity LSR mold heater.

• Journal of Korea Foundry Society
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• v.44 no.1
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• pp.3-8
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• 2024

Reducing industrial waste and improving the atmospheric environment recently have emerged as important tasks for the casting industry. Various types of artificial sand that can replace natural sand have been developed and used to solve problems that arise with the use of conventional foundry sand and to improve the foundry environment. However, only limited physical properties provided by overseas suppliers are known and in-depth comparative analyses with existing natural sand are lacking. For the design of the casting process, a wide range of thermal properties must be secured not only at room temperature but also at high temperatures. In addition, it is important to compare and analyze the differences in thermal properties between existing natural and artificial sand because changes in thermal properties require changes in the design of the casting method. In this study, the thermal behavior of the mold was analyzed through a thermal expansion test of mold blocks for natural and artificial sand., To this end, a thermal property test to evaluate thermal conductivity was performed by determining a temperature range. The results of the experiment, revealed that the thermal conductivity was 5-40% higher in artificial sand than in natural sand, and the coefficient of thermal expansion was about 15% lower for artificial sand. However, there was not a significant difference in specific heat regardless of the composition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.5
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• pp.575-582
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• 2010

In recent years, several rapid-mold-heating techniques that can be used for the injection molding of thin-walled parts or micro/nano structures have been developed. High-frequency induction heating, which involves heating by electromagnetic induction, is an efficient method for the rapid heating of mold surfaces. The present study proposes an integrated numerical model of the high-frequency induction heating process and the resulting injection molding process. To take into account the effects of thermal boundary conditions in induction heating, we carry out a fully integrated numerical analysis that combines electromagnetic field calculation, heat transfer analysis, and injection molding simulation. The proposed integrated simulation is extended to the injection molding of a thin-wall part, and the simulation results are compared with the experimental findings. The validity of the proposed simulation is discussed according to the ways of the boundary condition imposition.

• Design & Manufacturing
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• v.11 no.1
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• pp.45-49
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• 2017

Currently, a lot of efforts to make increases the manufacturing efficiency have tried and there is growing the interest to implementing the machining operation through CAM automation and optimization. This kind of movement has shown gradually in 5X milling as well as 3X milling task. By the way, in case of 5X milling, it is difficult to hire the CAM experts who is an experience for 5X machining and also it has too big trouble to use them due to high cost. For this reason, you can see the manufacturer who is concern the CAM S/W to provide the NC automation program that beginners can generate easily the 5X milling in short term and the existing 5X milling process can be improved. These requirements need to make a NC automation process including the practical machining strategies same as the generation by NC expert. In order to support this, it is necessary to directly apply the 3D machining part based on NC template which includes the machining procedures, standard cutter library, auto machine area selection, analyze tool for part shape, machining condition setting considering the material stiffness to be provided by CimatronE and it should be created the 5axis machining data by a minimized operation. With user-friendly, CimatronE's NC machining automation tools improve the 5-axis machining process and speed up the process, maximizing work efficiency and improving product productivity compared to existing machining tasks.

• Design & Manufacturing
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• v.11 no.1
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• pp.1-6
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• 2017

In these days, due to generalization of using smart mobile phone and wearable device such as smart watch, demand of Cover-glass and touch screen panel for protecting display increases. With increasing the demand of Cover-glass, slimming technique is promising for weight lightening, zero bezel. Cover-glass produced by this technique is required to decreasing thickness with increase strength. In the Cover-glass manufacturing process, mechanical processing and chemical processing has improve in the strength. Generally, Diamond electrodeposition wheel is used in mechanical process. Reinforced glass with the characteristics of the brittle and high hardness was manufactured by using a diamond electrodeposition wheel. At this time, Because of surface of the tool present non-uniform distribution of diamond particle, it has generate Loading of wheel and it has been decrease life of grinding tool, efficiency of grinding, quality and shape accuracy of workpiece. Thus Research is needed to controling particle distribution of diamond electrodeposition wheel uniformly. And it is necessary to study micro hole machining such as proximity senser hole, speaker hole positioned Cover-glass. Reinforced glass with the characteristics of the brittle and high hardness is difficult to machining. Processing of reinforced glass have generated wear of tool, micro cracks. Also, it is decreasing shape accuracy. In this paper, We conducted a study on how to control particle distribution uniformly about the diamond tool manufactured using elecetodeposition processing. It analyzed the factors that affect the arrangement of the particles in the electrodeposition process by design of experiment. And There is produced the grinding tool, which derives an optimum deposition conditions, for processing Cover-glass edge and the machinability was evaluated.

• Design & Manufacturing
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• v.14 no.2
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• pp.62-68
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• 2020

Recently, research on precise parts required in aerospace, ship, and automobile industries has been actively conducted. In this paper, electron beam drilling machining parameters were selected and experiments were conducted to compare processing characteristics analysis according to machining parameters through machining experiments of a vaporization amplification sheet to which STS 304 was applied. Also, as a result of measuring the machining. As the thickness gradually increased, it was confirmed that the electron beam could not reach the vaporization amplification sheet and thus melted on the surface of the material. As a result of the experimental analysis, it was analyzed that the vaporization explosion reaction of the vaporization amplification sheet was not normally performed due to the working distance (WD) according to the material thickness.