• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.84-84
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• 2004

다단 냉간단조 공정에서는 결함이 없는 재료의 유동, 금형내부의 완전한 충만과 금형의 수명향상 등을 위하여 예비성형체의 설계가 중요시되고 있다. 특히 최근 제품의 정밀도에 관심이 집중되어 냉간 상태에서 완제품으로 성형하여 후속 기계가공을 없앰으로써 재료의 절약, 에너지 절감, 가공공정수 단축 등 냉간단조를 고부가가치 가공의 유력한 수단으로 응용하려는 추세이다. 이러한 경우 예비성형체의 형상은 제품의 정밀도와 금형의 수명에 지대한 영향을 미친다.(중략)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4057-4064
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• 2014

In this paper, attempts were made to design a preform for a final punch inexpensively using the proposed approximate optimization method or metamodel-based simulation optimization. The design objective of this work is to achieve a uniform distribution of effective strains, the angle dimension of the preformed punch is chosen as a design variable, and maximum underfill ratio is used as a constraint. For this optimization, a computer simulation of a practical punch forging process is run using DEFORM software, in which a preformed punch(workpiece), a master punch(upper die), and a bottom die are dealt with. A validation method is introduced to determine if the simulation results match the actual forging process. In addition, this work presents the detailed design optimization procedure consisting of (i) generation of an initial metamodel, (ii) metamodel optimization, (iii) validation of metamodel-predicted optimum, and (iv) metamodel improvement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.973-976
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• 2004

So far, this report is written by knowledge and standard through several reference drawing and experienced contents with drawing hemming die. The contents about actual design is so huge that I will write about it next time. Timing chart is important to hemming die because of link position and numbers. Timing chart need a very much design time because link number and position have to applied for each case. In this paper developed an automatic timing chart and link position by relation and Pro/Program of Pro/Engineer. The method used relation rule of design parameter for timing chart. In the future, I believe that simple easy to correct and reasonable price hemming die will be producted.

• Journal of the Korean Society for Precision Engineering
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• v.4 no.1
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• pp.74-82
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• 1987

딥 드로오잉 시의 소재누르기판의 힘을 펀치의 변위 혹은 힘의 임의의 함수로서 제어 시킬 수 있는 서브프레스장치 및 유압장치를 제작하고 제어용 프로그램을 작성하여 시 험하였다. 제작한 장치를 인스트론 시험기에 설치하고 제어용 프로그램을 IBM퍼스널 컴퓨터를 사용하여 실행시킨 결과, 기계 제어 부분은 어셈블러언어로, 계산 부분은 고급 언어로 프로그램을 작성하여 링크시킨 후에 컴파일링하여 사용하는것이 제어의 응답성 및 정확도를 향상시킬 수 있음이 판명되었다. 또한, 소재누르기판의 힘의 제어에 필요한 이론 및 예비 결과들도 제시하였다.

• Horticultural Science & Technology
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• v.32 no.2
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• pp.184-192
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• 2014

Various types of unit packaging methods were applied for 'Fuji' apples during short-term cold storage and export simulation. Gas tightness of the package was controlled stepwise in the successive two-year experiments using different perforation treatments (none, punch hole, or pinhole) and sealing methods (tie v s. heat seal). Risk of tight packaging and effectiveness of macroperforation on weight loss and quality maintenance were analyzed as related to changes in gas concentration inside the packages. Immediately after harvest, each 5 apple units were packaged in $40{\mu}m$ polypropylene (PP) film bags, stored 4 weeks at $0^{\circ}C$, and then put on the shelf for one week at ambient temperature in the preliminary experiment, In the main experiment, export process was imposed after storage simulating 2 week refrigerated container shipment at $0^{\circ}C$ plus one week local marketing at ambient temperature. Non-perforated film packaging with relatively high gas tightness induced flesh browning caused by carbon dioxide accumulation regardless of the sealing methods. Among perforated film packaging, in contrast, atmospheric modification was partly established only in the pinhole treatment and flesh browning symptom was not observed in all the treatments. Even the punch hole perforated film packaging without gas tightness effectively reduced the weight loss, whereas had slight benefits for quality maintenance. Reduced perforation using pinhole treatment seemed to improve sensory texture, while effects on physicochemical quality were insignificant. Overall results suggest the need of more minute perforation treatments on the packaging film to ensure modified atmosphere effects on quality maintenance.