• 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.

• Design & Manufacturing
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• v.10 no.2
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• pp.50-54
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• 2016

In the semiconductor industry the final products were checked for several environments before sell the products. The burning test of memory and chip was implemented in reliability for all of parts. The memory and chip were developed to high density memory and high performance chip, so circuit design was also high integrated and the test bed was needed to be thin and fine pitch socket. LGA(Land Grid Array) IC socket with thin wall thickness was designed to satisfy this requirement. The LGA IC socket plastic part was manufacture by injection molding process, it was needed accuracy, stiffness and suit resin with high flowability. In this study, injection molding process analysis was executed for 2 and 4 cavities moldings with runner, gate and sprue. The warpage analysis was also implemented for further gate removal process. Through the analyses the total deformations of the moldings were predicted within maximum 0.05mm deformation. Finally in consideration of these results, 2 and 4 cavities molds were designed and made and tested in injection molding process.

• Design & Manufacturing
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• v.13 no.3
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• pp.53-58
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• 2019

This paper presents Artificial Neural Network(ANN) method to predict maximum injection pressure of injection molding machine and weights of injection molding products. 5 hidden layers with 10 neurons is used in the ANN. The ANN was conducted with 5 Input parameters and 2 response data. The input parameters, i.e., melt temperature, mold temperature, fill time, packing pressure, and packing time were selected. The combination of the orthogonal array L27 data set and 23 randomly generated data set were applied in order to train and test for ANN. According to the experimental result, error of the ANN for weights was $0.49{\pm}0.23%$. In case of maximum injection pressure, error of the ANN was $1.40{\pm}1.19%$. This value showed that ANN can be successfully predict the injection pressure and the weights of injection molding products.

• Design & Manufacturing
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• v.15 no.3
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• pp.45-49
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• 2021

In this study, during the injection molding process, a device was manufactured and evaluated that calculates a cooling time by measuring a vibration signal generated from a mold using an acceleration. The last two parts, one of which has a large magnitude change in the measured vibration signal of a mold, were divided into a cooling start section (paking end section) and a mold opening section, and the time difference at the relevant points was calculated as the cooling time. The cooling time was monitored on a 5-inch light guide plate mold by applying the method. The manufactured device was attached to a fixed base of mold to measure the cooling time, and data was obtained remotely using Bluetooth technology. Then, the measured cooling time was compared with the cooling time set in the injection molding machine to evaluate the accuracy. As a result of the experiment, the cooling times measured by the devices were 15.675±0.024 sec, 20.637±0.014 sec and 25.623±0.079 sec of each conditions. Also, the measurement results were shown with errors of 0.655±0.044 sec, 0.637±0.014 sec, and 0.662±0.013 sec, respectively.

• Proceedings of the CALSEC Conference
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• 2001.08a
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• pp.105-109
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• 2001

성형의 종류 ◈금속 성형 ㆍ 스탬핑(Stamping) ㆍ 정밀 블랭킹(Fine Blanking) ㆍ 딥 드로잉(Deep Drawing) ㆍ 다이캐스팅(Die Casting) ㆍ 인베스트먼트 주조(Investment Casting) ㆍ 분말 야금(Power Metallurgy) ㆍ 인발(Wire Drawing) ㆍ 압출(Extrusion) ㆍ 단조(Forging) ㆍ ㆍ코이닝(Coining) ㆍ... ◈비금속 성형 ㆍ 사출(Injection) ㆍ 압축(Compression) ㆍ 블로우 성형(Blow Molding) ㆍ 진공 성형(Vacuum Molding) ㆍ 발포 성형(Foam Molding) ㆍ 피복(Encapsulation) ㆍ 회전식(Rotational) ㆍ 주조(Casting) ㆍ 적층(Laminating) ㆍ 압출(Extrusion) ㆍ...(중략)

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.17-23
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• 2008

Development of die technology for holder and barrel dies is necessary according to minimization of lens assembly, image sensor, and connectors. In these cases, there are two technical problems arising from die design. One is determination of knock-out pin location in die set. Minimization of lens assembly size make it difficult to obtain ejecting space. The other is whether or not high-precision die technology is possible to reduce torque variation when holer and barrel products is assembled. In this study, multi-cavity die set was developed taking advantage of gear-driven ejecting method. In the developed technology, die manufacturing technology was guaranteed with a high-precision level.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.103-109
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• 2008

The sink mark on boss parts is generated by the volumetric shrinkage that is caused by both the molding thickness and the boss wall thickness. The volumetric shrinkage is caused by packing pressure and its amount tends to decrease by increasing the packing pressure. The packing pressure can therefore increase the flow rate to a boss part and causes the depth of sink mark to increase. As the molding thickness and the boss wall thickness in the boss part can increase the part volume, these may yield bad solidifying and also extend the molding cycle. In this paper, both the injection molding test and the flow analysis were carried out to investigate the effect of sink mark that was generated in the boss wall thickness of injection molded products. The sink mark could also be caused by thickness ratio of boss part. For a given thickness ratio of boss, several molding process parameters such as packing pressure, packing time and melt temperature, affecting to generation of the sink mark were discussed

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.99-102
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• 2008

Large injection molds commonly have molding defects such as flashes and variation of product thickness. In this study, we conducted injection molding CAE analysis to find out the cavity pressure and structural analysis to find out mold deflection as input load conditions injection pressure obtained from injection molding analysis. As the results from CAE analysis, we found which element is the most effective on the mold deflection and we suggested a mold design to minimize the mold deflection.

• Design & Manufacturing
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• v.17 no.3
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• pp.1-7
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• 2023

Blow molding is a manufacturing process in which thermoplastic preforms are preheated and then pneumatically expanded within a mold to produce hollow products of various shapes. The two-step process, a type of blow molding method, requires the output of multiple infrared lamps to be adjusted individually, so the process of finding initial conditions hinders productivity. In this study, digital twin technology was applied to solve this problem. A blow molding simulation technique was established and simulation-based metadata was generated. A response surface ROM (Reduced Order Model) was built using the generated metadata. Then, a dynamic ROM was constructed using the results of 3D heat transfer analysis. Through this, users can quickly check the product wall thickness uniformity according to changes in the control value of the heating lamp for products of various shapes, and at the same time, check the temperature distribution of the preform in real time.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.65-70
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• 2014

Warpage of top packages to form thin package-on-packages was measured with progress of their process steps such as PCB substrate itself, chip bonding, and epoxy molding. The $100{\mu}m$-thick PCB substrate exhibited a warpage of $136{\sim}214{\mu}m$. The specimen formed by mounting a $40{\mu}m$-thick Si chip to such a PCB using a die attach film exhibited the warpage of $89{\sim}194{\mu}m$, which was similar to that of the PCB itself. On the other hand, the specimen fabricated by flip chip bonding of a $40{\mu}m$-thick chip to such a PCB possessed the warpage of $-199{\sim}691{\mu}m$, which was significantly different from the warpage of the PCB. After epoxy molding, the specimens processed by die attach bonding and flip chip bonding exhibited warpages of $-79{\sim}202{\mu}m$ and $-117{\sim}159{\mu}m$, respectively.