• Journal of the Korean Institute of Gas
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• v.18 no.1
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• pp.46-51
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• 2014

The purpose of this paper is to study of the vehicle lamp manufacturing system composing ultrasonic waves connection process. Making lamp assembly plant, it was produced in the separate process as the injection molding, ultrasonic waves bonding, annealing in the constant temperature, lamp assembling and packing. But the improvement method producing the lamp was added with one-step process by one automation technique. As a result, welding with ultrasonic waves process, the method decreased the energy consumption and noise during ultrasonic waves welding. Therefore, this method used the mathematics modeling for checking validity, it selected the stability and suitable controller using transfer function of plant and bode chart. In this study, the $180^{\circ}$ revolution control system to turn injection part upside down was $M_{eq}\;lcos{\theta}(t)$ because of gravity influence. It effected to unstable condition a system. For solving this problem, it aimed the linearization and stabilization of system by elimination $M_{eq}\;lcos{\theta}(t)$ as applying Free-forward control technique.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.473-476
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• 2008

Due to the pursuit of high function and international price increase in the field of construction, the application of the secondary product using cement is on the increase gradually in the construction industry in the pursuit of economic cost reduction by the shortening of the construction time like Expediting and the dry construction method at the same time. However, it is in very urgent situation of measures to improve the structural performance or durable performance because it is limited for use in terms of panel in interior exterior building or functional repair reinforce as yet. Accordingly, this study is to investigate applicability of permanent Formwork like mould with the structural performance or excellent durable performance in the field of construction, and to derive optimum mixture in the performance and quality of manufacture. As a result of analysis comparison with the dynamic and durable properties of vacuum extrusion molding high toughness cement panel according to the mixture of four conditions, this study has found that the test body of mixing ECC-DP3 using small filler and large granulated blast furnace slag and powder flame retardant had excellent relative hardness and bending stress strain. The durable performance has shown excellent tendency by the decrease of porosity and enhancement of water-tightness.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.1
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• pp.31-39
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• 2014

For mobile application, semiconductor packages are increasingly moving toward high density, miniaturization, lighter and multi-functions. Typical wafer level packages (WLP) is fan-in design, it can not meet high I/O requirement. The fan-out wafer level packages (FOWLPs) with reconfiguration technology have recently emerged as a new WLP technology. In FOWLP, warpage is one of the most critical issues since the thickness of FOWLP is thinner than traditional IC package and warpage of WLP is much larger than the die level package. Warpage affects the throughput and yield of the next manufacturing process as well as wafer handling and fabrication processability. In this study, we investigated the characteristics of warpage and main parameters which affect the warpage deformation of FOWLP using the finite element numerical simulation. In order to minimize the warpage, the characteristics of warpage for various epoxy mold compounds (EMCs) and carrier materials are investigated, and DOE optimization is also performed. In particular, warpage after EMC molding and after carrier detachment process were analyzed respectively. The simulation results indicate that the most influential factor on warpage is CTE of EMC after molding process. EMC material of low CTE and high Tg (glass transition temperature) will reduce the warpage. For carrier material, Alloy42 shows the lowest warpage. Therefore, considering the cost, oxidation and thermal conductivity, Alloy42 or SUS304 is recommend for a carrier material.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.92-101
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• 2018

It is important to inherit and develop the unique cultural characteristics of each country and region in the trend of globalization. The traditional lighting fixtures in China are the main artifacts that can be used to extract the cultural aesthetics and practicality of the people, and are a major relic of the people's cultural sensitivities and practicalities. The purpose of this study is to understand the background of the time and the meaning of national culture through the lighting equipment of the most revived Tang Dynasty in Chinese history. The purpose of this paper is to examine the development trend of lighting equipment in the Tang Dynasty through the recognition of the social background, religious thought, cultural characteristics, and characteristics of lighting fixtures in the Tang Dynasty. In this paper, we analyzed seven factors (function, molding, fuel, usage space, usage method, religious thought, and living environment) of the Tang dynasty lighting fixtures through multiple factor analysis method. In addition, the Tang Dynasty period lighting fixtures had four trends: "popularization of lighting, universal simplification of molding, diversification of use, and spread of Buddhist influence." This tendency has a meaning to provide a new motive for modern lighting design in the context of cultural uniqueness and perspectives.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.8
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• pp.824-833
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• 2012

The shrinkage and the warpage of the moulded part are influenced by the design of the product and injection mould. In a flat part with a partly thick volume, the warpage of the flat part is created from the difference of the shrinkage between thin and thick regions. The warpage of the flat part with a partly thick volume can be reduced by a proper design of the cooling system in the injection mould. The goal of this paper is to design properly cooling channels of injection mould to manufacture a flat part with a partly thick volume. The conformal cooling channel is adopted to improve cooling characteristics of a region with the thick volume. The linear cooling channels are assigned to the other region. The proper design of the conformal cooling channels is obtained from three-dimensional injection molding analysis for various design alternatives. The moulding characteristics of the designed mould with both conformal and linear cooling channels are compared to those of the mould with linear cooling channels from viewpoints of temperature, shrinkage and warpage of the moulded part using numerical analysis. Injection mould with both conformal and linear cooling channels for the flat part with a partially thick volume is fabricated. In addition, injection moulding experiments are performed using the fabricated mould. From the results of the injection moulding experiments, it has been shown that the designed mould can successfully fabricate the flat part with a partially thick volume.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.1
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• pp.41-45
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• 2018

As the size of semiconductor chip shrinks, the electronic industry has been paying close attention to fan-out wafer level packaging (FO-WLP) as an emerging solution to accommodate high input and output density. FO-WLP also has several advantages, such as thin thickness and good thermal resistance, compared to conventional packaging technologies. However, one major challenge in current FO-WLP manufacturing process is to control wafer warpage, caused by the difference of coefficient of thermal expansion and Young's modulus among the materials. Wafer warpage induces misalignment of chips and interconnects, which eventually reduces product quality and reliability in high volume manufacturing. In order to control wafer warpage, it is necessary to understand the effect of material properties and design parameters, such as chip size, chip to mold ratio, and carrier thickness, during packaging processes. This paper focuses on the effects of thickness of chip and molding compound on 12" wafer warpage after PMC of EMC using finite element analysis. As a result, the largest warpage was observed at specific thickness ratio of chip and EMC.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1487-1492
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• 2010

The objective of this study is to design the conformal cooling channels for the mould of a plastic drawer of a refrigerator by analysis of three-dimensional injection molding. In order to obtain the desired design of the conformal cooling channels, the influence of the diameter and the position of the conformal cooling channels on the moulding characteristics and the product qualities were quantitatively examined. From the results of the examination, an optimal design of the conformal cooling channels, which ensures uniform cooling and minimum potential deformation of the molded drawers, was estimated. By comparing the designed mould and a conventional mould with linear cooling channels from the viewpoints of the product qualities as well as cooling and cycle times, it was shown that the mould with conformal cooling channels can simultaneously improve the productivity of the injection moulding process and the product qualities.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.11
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• pp.3538-3548
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• 1996

In this study, as a part of basic study for developing the simulation program for the assemssment of reliability of electronic EMC packaging which covers from EMC mixing step to thermal analysis, comparison between a measured and predicted values of material properties of EMC and finitde element analysis of thermal stress are performed. For the experimental testing specimens of fifty, sixty hive and eighty percent filler($13\mu m$, spherical silica) weight fraction are fabricated using tranfer molding. Coefficient of thermal expansion, elastic modulus and thermla conductivity are measured using these specimens and then these measured values are compared with the predicted values by various equations ( such as dilute suspension method. self consistent method, generalized self consistent method, Hashin-Shtrikman's bounds. Shapery's bounds, Nielsen's method and others). Measured values are distributed within the upper and lower bounds of equations. Measured elastic modulus and coefficient of thermal expansion approaches closely the perdicted values with self consisten mehtod and upper bound of Shaperys equation respectively. However small differences of thermal conductivity between the different filler volume fraction are obserbed. FEM analysis indicates that firstly stress is concentrated at the corner section of EMC and secondly EMC with eighty percent filler weight fraction shows less thermal stress when package is cooling down and relatively high thermal stress when package is heating up.

• Design & Manufacturing
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• v.12 no.2
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• pp.34-39
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• 2018

The biggest topics in the automobile industry are light weightening and fuel efficiency improvement. There's a lot of research going on. It is focused on light weight materials. Light weight material is seen as the best way to reduce fuel consumption and to solve the problem of environmental pollution and resource depletion. For the light weight materials, new materials such as aluminum, magnesium, and carbon-hardening materials can be found. Research on the joining techniques of dual materials, improvement of material properties by improving the method of manufacture of existing materials, and studies on ultra-high strength steel sheets are expected to take up the most weight in lightweight materials. As the strength of the ultra-high strength steel sheets increases during forming, it is difficult to obtain dimensional precision due to the increase in elastic restoring force compared to mild or high strength steel sheets. Spring back is known to be affected by a number of factors due to poor plastic molding, and can be divided into the effects of the material spraying and the process. The study on the plasticitic variables were studied as plasticitic factors that can be controlled by a part company. Tensile testing of ultra-high strength materials was conducted to derive properties for plasticitic analysis and to analyze spring back with two factors controlling the height of the bead and blank holding force by adding tensile force and controlling the flow rate.

• Archives of Plastic Surgery
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• v.39 no.4
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• pp.338-344
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• 2012

Background It is known that nonsynostotic plagiocephaly does not spontaneously improve, and the craniofacial deformities that result from it. This study was conducted to analyze the effectiveness of helmet therapy for the nonsynostotic plagiocephaly patient, and to suggest a new treatment strategy based on this analysis. Methods A total of 108 pediatric patients who had undergone helmet therapy after being diagnosed with nonsynostotic plagiocephaly were included in this study. The patients were classified according to the initiation age of the helmet therapy, severity, and helmet wearing time. The treatment effect was compared using cranial vault asymmetry (CVA) and the cranial vault asymmetry index (CVAI), which were obtained from diagonal measurements before and after therapy. Results The discrepancy of CVA and CVAI of all the patients significantly decreased after helmet therapy. According to the initiation time of helmet therapy, the treatment effect was best at 5 months old or less. The helmet wearing time per day was proportional to the treatment effect up to 20 hours. In addition, the rate of the successful treatment (final CVA ${\leq}$ 5 mm) significantly decreased when the initiation age was 9.1 months or older and the treatment period was less than 7.83 months. Conclusions This study showed the effectiveness of the helmet therapy for nonsynostotic plagiocephaly patients. Based on analysis of this study, helmet therapy should be started at the age of 9 months or younger for 7.83 months or more, and the helmet wearing time should be more than 20 hours a day.