• 한국기계가공학회지
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• 제18권3호
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• pp.82-87
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• 2019

Recently, plastic materials have become more diversified, and the development of materials with excellent mechanical properties and plasticity has enabled wider application, miniaturization, and refinement of injection molded products. As a result, the utilization of these products in household goods, electronics, automotive parts, and aircraft parts is increasing in almost all industries. Injection molded parts are often used externally on finished commercial products. This means that the injection mold industry is very important to the value of these products. For this reason, the industry is performing research on the precision and efficiency of the injection molding process. In this study, we investigated the applicability of the core in core cooling method to the problem of product deformation due to temperature variation in existing injection mold designs. We also characterized the cooling performance of an injection mold when using this cooling method.

• Journal of the Korean Wood Science and Technology
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• 제32권1호
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• pp.1-8
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• 2004

생장속도가 빨라서 단위면적당 Biomass의 생산량이 많은 어저귀(Indian mallow, Abutilon avicennae G.)를 원료로 하여 펄프화하였으며, 제조한 한지의 물리적·기계적·현미경적 특성에 관하여 비교 검토하였다. 제조한 한지의 특성을 살펴보면 광학적, 강도적, 현미경적인 특성에서 설포메틸 펄프화법이 우수한 결과를 나타냈고, 장섬유인 인피부 펄프에 대한 단섬유인 목질부 펄프의 혼입량 증가에 따른 변화에 있어 지질(밀도, 백색도, 불투명도, 지합)의 변화는 점차 증가했으나, 강도는 감소하는 경향을 나타냈다.

• 한국재료학회지
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• 제32권12호
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• pp.538-544
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• 2022

In existing ceramic mold manufacturing processes, inorganic binder systems (Si-Na, two-component system) are applied to ensure the effective firing strength of the ceramic mold and core. These inorganic binder systems makes it possible to manufacture a ceramic mold and core with high dimensional stability and effective strength. However, as in general sand casting processes, when molten metal is injected at room temperature, there is a limit to the production of thin or complex castings due to reduced fluidity caused by the rapid cooling of the molten metal. In addition, because sodium silicate generated through the vitrification reaction of the inorganic binder is converted into a liquid phase at a temperature of 1,000 ℃. or higher, it is somewhat difficult to manufacture parts through high-temperature casting. Therefore, in this study, a high-strength ceramic mold and core test piece with effective strength at high temperature was produced by applying a Si-Na-Ti three-component inorganic binder. The starting particles were coated with binary and ternary inorganic binders and mixed with an organic binder to prepare a molded body, and then heat-treated at 1,000/1,350/1,500 ℃ to prepare a fired body. In the sample where the two-component inorganic binder was applied, the glass was liquefied at a temperature of 1,000 ℃ or higher, and the strength decreased. However, the firing strength of the ceramic mold sample containing the three-component inorganic binder was improved, and it was confirmed that it was possible to manufacture a ceramic mold and core via high temperature casting.

• 문화기술의 융합
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• 제3권3호
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• pp.43-49
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• 2017

본 연구는 중소기업의 정보화를 추진함에 있어, 정보화 중에서도 중단기적인 도입 성과를 낼 수 있는 생산정보관리시스템 구축을 위하여, 화학제조업 분야의 핵심 업무 프로세스에 대하여 표준화를 연구하고 그에 따른 생산정보관리시스템을 구축 적용하는데 제공하고자 한다. 화학제조업 생산정보관리시스템 표준화를 위한 개발방법론은 중소기업기술정보진흥원에서 기 연구 개발된 생산정보관리시스템 개발 방법론(PSDM)을 적용하며, 표준화 대상은 시스템 구성도, 업무절차 흐름도, Menu Structure 등과 같이 시스템구축 시 골격이 되는 핵심 업무 프로세스이다. 본 연구로 생산정보관리시스템을 구축하고자 하는 화학제조업 중소기업 및 관련 전문 IT업체들이 표준화된 핵심 업무 프로세스를 적용하여 시스템을 보다 효과적으로 구축 할 수 있으며, 시스템에 대한 구축 용이성과 신뢰성을 제공하며 아울러 핵심 업무 프로세스의 활용이 극대화되기 위해서 사후관리 교육훈련 및 유지보수 방안도 제시하고 있다. 본 연구 결과를 적용함으로써 생산 공정의 불합리한 요소제거, 생산제품 품질 향상, 생산비용절감이 가능하다.

• 산업공학
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• 제25권1호
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• pp.106-113
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• 2012

There are few factors like a due date observance of the customer's order, reducing the manufacturing lead time, and minimizing the inventory investment to successfully run the manufacturing system. It is difficult for corporation and a person concerned to be offered indicators to achieve few factors mentioned above from complex manufacturing systems having much fluctuations. Simplified-DBR based on TOC(Theory of Constraints) is a management paradigm which can offer indicators to effectively face with fluctuating market's needs when market's demand is smaller than a capacity of manufacturing system. This paper is offering a core indicator and management model which is needed to successfully run the manufacturing system for corporation and a person concerned who have short experience and knowledge and newly construct Sinplified-DBR manufacturing system. Thus, this paper provides a systemic guidance in the offered model through the simulation.

• Asia pacific journal of information systems
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• 제7권1호
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• pp.25-48
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• 1997

This study examines whether expenditures in information technology (IT) are associated with increases in the Tobin's q ratios a measure of organizational performance. It uses two groups of sample, Korean and American firms that disclose IT expenditures. For the all-firms group of each country, the association between IT expenditures and Tobin's q ratios is positive and statistically significant. But the association varies among industries. For Korean firms, IT expenditures appear to increase Tobin's q ratios for the machine and equipment manufacturing industry group (SIC3-2). IT expenditure ratio of this group as a percent of total sales is highest among the industry groups. For all service industry groups(SIC4&5), the estimated coefficient of IT expenditures is positive but statistically insignificant. For American firms IT expenditures in most of the manufacturing industry groups appear to increase only a little, if at all, for the Tobin's q ratios. But IT expenditures appear to have a greater impact on Tobin's q ratios for all service industries (SIC4-7). For three service industries tested (transportation and telecommunication- SIC4, financial- SIC6, consulting and other service industry- SIC7), the estimated coefficient of IT expenditures is positive and statistically significant. The evidence from both Korean and American firms suggests that IT expenditures in service industries provide a greater impact on an organizational performance than ones in manufacturing industry. To test whether service industries use a competitive strategy utilizing IT as a core competence, the samples ore divided into two groups, service and manufacturing industry. For Korean firms, both IT and R&D expenditures in manufacturing industry are associated with increases in Tobin's q ratios. But for service industry, the estimated coefficient of only IT expenditure is positive. For American firms, the estimated coefficients of both IT and advertising and R&D (ARD) expenditures in manufacturing industry are positive but the coefficient of only ARD is statistically significant. For service industry, the estimated coefficient of only IT expenditure is positive and statistically significant. The evidence may suggest that manufacturing industry uses both R&D and IT strategies to increase a competitive advantage but uses R&D strategy as a core competence. However, service industry uses IT strategy as a core competence to increase a competitive advatage.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.190-195
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• 1998

The guidance core is a principal part installed between the ink and the pen nib for the function of supplying ink to paper with reqularity. The current measurement of this product, Guidance core, in service is done by on operator with a micrometer, which could result in the decrease of productivity and working efficiency as well as causing errors. In this study, the existing measurement of the dialmeter of the Guidance core in the centerless grinding process is changed to the inprocessor measurement which enables consecutive measurement during the production of the Guidance core, and this system is also developed to work properly under bad circumstances and to have superior reliance and operational efficiency.

• 한국기계가공학회지
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• 제19권6호
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• pp.43-48
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• 2020

This study explores the compression molding of diffractive-aspheric lenses using GeSbSe chalcogenide glasses. A mold core with diffractive structure was prepared and a chalcogenide glass lens was molded at various temperatures using the corresponding core. The effect of molding temperature on the transcription characteristics of diffractive structure was examined, by measuring and comparing the diffractive structure between the mold core and the molded chalcogenide glass lens using a microscope and a white light interferometer. In addition, the applicability of the molded lens for thermal imaging was evaluated, by measuring the form error.

• 한국기계가공학회지
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• 제12권3호
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• pp.13-20
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• 2013

The present research aims to develop the aluminum disc brake replacing the existing cast iron disc brake. Material such as aluminum using FEM numerical analysis in order to improve the characteristics of each element, we analyze the performance characteristics and braking time you try to change. We try to lay the foundation for the development of an aluminum disc by investigating performance characteristics of the existing cast iron disc brake and comparing them with those of the aluminum disc. This involves FEM dynamics analysis for disc materials and experimental tests using the brake dynamometer. From this study, the results of 7075 aluminum braking performance can be seen that the best.

• 한국기계가공학회지
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• 제14권4호
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• pp.8-13
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• 2015

In this study, we fabricated and characterized a nanostructured surface based on a plastic injection molding with a local mold heating (LMH) system. A metal mold core with a closed packed nano convex array (CVA) was achieved by integrated engineering procedures: (1) master template fabrication by anodic aluminum oxidation (AAO), (2) nickel electroforming (NE) process, and (3) post-processing by precision machining. The nickel mold core was utilized to replicate a surface with a closed packed nano concave-array (CCA) based on injection molding using cyclic olefin copolymer (COC) as a plastic material. In particular, an LMH system was introduced to enhance transcription quality of the nano structures by delaying solidification of molten polymer near the surface of the mold core.