• 소성∙가공
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• 제17권2호
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• pp.107-112
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• 2008

In order to investigate the residual stress evolution during the leveling process of hot rolled high strength coils for cold forming, the in-plane residual stress of plate sampled at SPM, rough leveler and finish leveler were measured by cutting method. Residual stress was localized near the edge of plate. As the thickness of plate was increased, the size of residual stress region was expanded. The gradient of residual stress within the plate was reduced during the leveling process. But the residual stress itself was not removed completely within the ranges of tested conditions. The exact camber of cut plate was able to be predicted by the measurement of residual stress distribution after leveling of the plate.

• 소성∙가공
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• 제20권6호
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• pp.427-431
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• 2011

In general, hot stamped component is trimmed by costly and time consuming laser cutting when the material strength is over 1,500MPa. The aim of this work was to demonstrate that the trimming die life is improved and the trimming load is decreased by lowering the strength of the region to be trimmed. The model employed in this study was a hat shape, similar to the cross section of many hot stamped products. FE-analysis of hot stamping process was performed to evaluate the effect of tool shape on cooling rate at the area to be trimmed. The best tool shape was thus identified, which created slower cooling and lower hardness at the region to be trimmed. The wear at the cutting tool edge was also reduced.

• 소성∙가공
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• 제12권3호
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• pp.208-213
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• 2003

The methodology to design initial blanks considering the reduction of both springback and flange trimming amounts is studied. Three dimensional forming analysis of a trial blank Is first carried out using FEM and the tentative Initial blank shape is then determined by cutting the outer edge of the trial blank whose shape is nearly matched with the trimming line. During the shaping the blank edge, tile movement of blank outer line is described with random variables to reduce the sensitivity of initial blank geometry. After performing 2-D FEM forming and springback simulations for selected sections and optimizing the trimming and springback amounts in terms of section length of the blank, the initial blank is finally determined. In order to see tile springback reduction in the initial blank determined by the proposed method, a stepped s-rail is stamped and the sppingback is measured. The springback of newly designed initial blank of stopped s-tail is tremendously reduced.

• 한국정밀공학회지
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• 제19권7호
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• pp.97-105
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• 2002

The use of rapid prototyping (RP) has reduced time to market, cut total costs and improved product quality by giving design and manufacturing teams the opportunity to verify and fine tune designs before committing them to expensive tooling and fabrication. In order to improve their unique characteristics according to the working principles, Variable Lamination Manufacturing process (VLM-ST) and corresponding CAD/CAM software (VLM-Slicer) is developed. The objective of this study is to improve the accuracy of VLM-ST process, and it can be done by offset fur cutting error correction, cutting path overrun fur sharp edge and reference shape generation for off-line stacking. It has been shown that, through the verification experiments for given practical shapes, the proposed algorithms are effective for diverse categories of three-dimensional shapes.

• 한국국방경영분석학회지
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• 제36권1호
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• pp.103-121
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• 2010

방위산업은 고도의 첨단 기술이 집약된 고부가 가치 산업으로 글로벌 시대의 신성장동력으로 대두되고 방산수출은 한국 경제 활성화 뿐만 아니라 국가 브랜드 가치 창출에도 중요한 분야로 인식되고 있다. 그러나 방산수출의 중요성에 대한 공감대가 형성되어 실제로 괄목할만한 실적을 올리고는 있지만 국방비 증가율은 갈수록 둔화되고 R&D투자 규모도 크지 않으며, 핵심기술관리 및 첨단 무기체계 개발에 많은 제약이 있다. 따라서 본 논문에서는 방산수출의 시스템적 구조를 분석하여 그 특징을 파악하고 방산수출의 구조를 정상적으로 움직이게 하는 레버리지를 찾아내고자 한다. 그리고 레버리지를 전략화하는 과정을 통해 방산수출 선진국 진입을 위한 최적의 정책 방향을 제시하고자 한다.

• Journal of Information Technology Applications and Management
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• 제12권1호
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• pp.91-109
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• 2005

The reason why modern companies adopt cutting-edge technologies aggressively is mainly due to maintain the competitiveness in this cut-throat business environment. One of the most important technology factors to maintain the competitiveness in this modern e-business era is how to adopt and apply information technology(IT). More and more companies are trying to implement their management strategies by applying IT, and therefore it is now important to understand IT strategy. Many of leading-edge companies believe that they need a structured and systematic approach, called ISP (Information Strategy Planning), to secure competitive IT capability, and heavily invest their resources to achieve the excellence in IT. However, eventual effects from those investments are not always proportional since every investment has its own investment parameters and objectives. In this research, we tried to develop a systematic model to verify the relation between the business competitiveness and ISP. First, in order to include the factor 'ISP', we modified the models suggested by past research results, and then analyzed the influences from IT investments and quality of ISP on the IT excellence of businesses. To prove the validity of the developed model, several sets of surveys were performed for 66 companies in various industries including electronics, manufacturing, finance, and service. The result of the research has shown that the quality of ISP impacts more on a corporate's business competitiveness, but none on business output.

• Design & Manufacturing
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• 제9권2호
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• pp.6-9
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• 2015

The objective of manufacturing knowledge sharing platform is to convert the production experience like a worker's know-how into quantitative values, to construct database of the process technologies and to share the technologies systematically via web portal service. In addition, the knowledge sharing platform contains the total production processes of automobile and mobile products such as information of experts, facilities, and cutting-edge R&D outputs. Automobile, telecommunication mobile, and semiconductors account for a large amount of Korea's export industry rate. These industries need production technology which is a result of converting worker's know-how and R&D. Manufacturing knowledge portal aims to enable transforming production experience such as worker's know-how into standardized form for constructing database and sharing technologies systematically. Manufacturing knowledge portal can contribute to small and mid-sized manufacturing companies with further improvements.

• 한국기계가공학회지
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• 제14권4호
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• pp.160-166
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• 2015

Ultrasonic machining (USM) has been considered a new, cutting-edge technology that presents no heating or electrochemical effects, with low surface damage and small residual stresses on brittle workpieces. However, nowadays, many researchers are paying careful attention to the disadvantages of USM, such as low productivity and tool wear. On the other hand, in this study, a high-performance rotary ultrasonic drilling (RUD) spindle is designed and assembled. In this system, the core technology is the design of an ultrasonic vibration horn for the spindle using finite element analysis (FEA). The maximum spindle speed of RUM is 9,600 rpm, and the highest harmonic displacement is $5.4{\mu}m$ noted at the frequency of 40 kHz. Through various drilling experiments on glass workpieces using a CVD diamond-coated drill, the cutting force and cracking of the hole entrance and exit side in the glass have been greatly reduced by this system.

• 한국축산시설환경학회지
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• 제18권2호
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• pp.85-90
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• 2012

In Korea, livestock has grown into the most value-added business in the agricultural and forest industry. But due to the recent outbreak of deadly infectious diseases such as foot-and-mount disease and avian influenza (AI), the demand for IT-enabled cutting-edge management system is getting stronger. As for humans, pilot projects and researches concerning U-healthcare have been carried out since early 2000. So this study explored the current progress of U-healthcare introduction, and suggested the strategies to develop technologies of collecting, processing, and utilizing information; to apply elements for a service model development and prioritization; to provide policy and institutional support. Therefore it is expected to vitalize the livestock U-healthcare in the future through continuous study based on these results.

• 한국정밀공학회지
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• 제19권7호
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• pp.71-79
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• 2002

A new rapid prototyping process, Variable Lamination Manufacturing using a 4-axis-controlled hotwire cutter and expandable polystyrene foam sheet as a laminating material of the part (VLM-S), has been developed to reduce building time and to improve the surface finish of parts. The objective of this study is to reconstruct the surface of the original 3D CAD model in order to generate mid-slice data using the advancing front technique. The generation of 3D layers by a 4 axis-controlled hot-wire cutter requires a completely different procedure to generate toolpath data unlike the conventional RP CAD systems. The cutting path data for VLM-S are created by VLM-Slicer, which is a special CAD/CAM software with automatic generation of 3D toolpath. For the conventional sheet type system like LOM, the STL file would be sliced into 2D data only. However, because of using the thick layers and a sloping edge with the firstorder approximation between the top and bottom layers, VLM-Slicer requires surface reconstruction, mid-slice, and the toolpath data generation as well as 2D slicing. Surface reconstruction demands the connection between the two neighboring cross-sectional contours using the triangular facets. VLM-S employs thick layers with finite thickness, so that surface reconstruction is necessary to obtain a sloping angle of a side surface and the point data at a half of the sheet thickness. In the process of the toolpath data generation the surface reconstruction algorithm is expected to minimize the error between the ruled surface and the original parts..