• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 춘계학술대회 논문집
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• pp.74-78
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• 1992

외부가 비축대칭인 튜브의 수방압출은 자동차와 항공기등의 복잡한 부품을 만드는데 많이 사용된다. 이런 후방압출 제품의 변형 상태는 저자들의 논문에서 이미 밝힌 바와 같이 복잡하다. 그래서, 외부가 비출대칭인 튜브형상의 후방압출은 근래에 와서 연구되었다. 본 연구에서는 저자들의 논문 에서 제시된 동적가용속도장을 수정하여 비축대칭인 소재에서 내부가 원형인 튜브의 후방압출의 최종 단계를 해석하 고자 한다. 해석의 적용예로서는 정다각형 소재와 모서리가 둥근 직사각형(rounded rectangle)소재를 택하였다 제시된 속도장으로부터 단면 감소율과 형상비(aspect ratio)에 대하여 압출 하중과 압출된 소재의 평균 높이가 결정된다. 이론적인 결과와 비교하기 위하여 퓰림처리된 AIST-2024 알루미늄 소재로 실험하였다.

• 대한기계학회논문집
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• 제14권1호
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• pp.1-12
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• 1990

본 연구에서는 자유단조용 프레서를 이용하여 돌출부가 있는 비대칭 중공형단 조 제품을 생산할 수 있도록 금형장치를 설계.제작하고, Fig.1에서 보는 바와 같이 경 사진 돌출부가 있는 비축대칭 복합단조에 UBET를 적용하여 해석하였다. 단조시편은 원주형태를 가지도록 하였다. 즉 원주형 소재가 요구되는 비축대칭 단조제품으로 변 형되는 과정에서 단조하중, 재료가 돌출부를 충만하도록 하는 유동특성, 재료가 돌출 부로 차들어가는 속도 등에 영향을 주는 인자(예:펀치 직경의 크기, 금형 상하면의 각 도)의 특성을 이론적으로 해석하고 실험으로 확인하였다.

• 한국정밀공학회지
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• 제19권2호
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• pp.195-202
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• 2002

An automated process planning system for cold forging of non-axisymmetric parts of comparatively simple shape was developed in this study. Programs for the system have been written with Visual LISP in the AutoCAD using a personal computer and are composed of four main modules such as input module, shape cognition and shape expression module, material diameter determination module and process planning module. The design rules and knowledges for the system are extracted from the plasticity theories, handbook, relevant reference and empirical knowledge of field experts. Generally, in forging, only front view is needed for expression of axisymmetric parts, but non-axisymmetric parts need front and plane view. At the plane, this system cognizes the external shape of non-axisymmetric, parts - number of sides of regular polygon and radius of a circle circumscribing the polygon of n sides. At the front view, the system perceives diameter of axisymmetric portions and height of primitive geometries such as polygon, cylinder, cone, concave, convex, etc.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.241-244
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• 2010

기존의 재래식, 전단, 튜브 스피닝이 모두 축대칭 제품의 형상화된 맨드릴을 사용하여 가공하여 왔다. 이러한 고전적 기법에서 한걸음 더 나아가 비축대칭, 열처리를 동반한 스피닝, 맨드릴이 자유로운 새로운 공법이 시도되고 있다. 본 조사에서는 주로 자유 맨드릴 공법에 대하여 동향을 조사하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 추계학술대회논문집
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• pp.22-25
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• 1999

'There are a lot of process variables, exerted influence on the formability of products, in deep drawing process. Particularly, it is important that the punch and die shape radius of the process variables. Though researches have been performed on the deep drawing of sheet metal forming, like this study, but it is insufficient the actual circumstances that researches for process variables of the non-axisymmetric deep drawing products. In this study, An effect on thickness distribution is grasped as alteration of the punch and die shape radius in the process of non-axisyrnmetric deep drawing products, and then the optimal punch and die shape radius were presented, they were verified by the numerical analysis method (FEM).

• 소성∙가공
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• 제10권3호
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• pp.185-192
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• 2001

In order to obtain the optimal products in deep drawing process, elliptical deep drawing tests were carried out with several shape radii of the punch and die. As parameters on testing, shape radii of the punch and die were selected. In addition, the conventional shape radii have been determined by trial-and-error using industrial experience and post processing test, and only approximate shape radii of the punch and die have been presented. The optimal shape radii of the punch and die in elliptical deep drawing process with biaxisymmetric blank shape are proposed. In this study, we suggest the appropriate conditions to be applicable to the actual manufacturing processes through the experiment and finite element method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.527-530
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• 1997

An automated process planning system for cold forging of non-axisymmetric parts of comparatively simple shape was developed in this study. Programs for the system have been written with Visual LISP in the AutoCAD using a personal computer and are composed of four main modules such as input module, shape cognition and shape expression module, material diameter determination module and process planning module. The design rules and knowledges for th system are extracted from the plasticity theories. handbook, relevant reference and empirical knowledge of field experts. Generally, in forging, only front view is needed for expression of axisymmetric parts, but non-axisymmetric parts are needed both front view and plane. At the plane, this system cognizes the external shape of non-axisymmetric parts - number of sides of regular polygon and radius of a circle circumscribing the polygon of n sides. At the front view, the system perceives diameter of axisymmetric portions and hight of primitive geometries such as polygon, cylinder, cone, concave, convex, etc.

• 소성∙가공
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• 제4권4호
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• pp.390-397
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• 1995

A simple kinematically admissible velocity field is proposed to determine the final-stage extrusion load and the average extruded length in the square-die forward extrusion of non-axisymmetric bars from circular billets. The proposed velocity field is applied to the square-die extrusion of trochoidal gear-shaped bars and rectangular-shaped bars. The profile function of a rectangle is approximated by using a Fourier series. Experiments have been carried out with hard solder billets at room temperature. The theoretical predictions of the extrusion load are in good agreements with the experimental results and there is generally reasonable agreements in average extruded length between theory and experiment.

• 소성∙가공
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• 제8권6호
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• pp.591-603
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• 1999

A computer-aided process planning system for rotationally symmetric deep drawing products has been developed. The application for non-axisymmetric components, however, has been reported yet. Therefore, this study investigates process sequence design in deep drawing process and constructs a computer-aided process planning system for non-axisymmetric motor frame products with elliptical shape. The system developed consists of three modules. The first one os a 3-dimensional modeling module to calculate surface area for non-axisymmetric products. The second one is a blank design module that creates an oval-shaped blank with the identical surface area. The third one is a process planning module based on production rules that play the best important roles in an expert system for manufacturing. The production rules are generated and upgraded by interviewing with field engineers. Especially, drawing coefficient, punch and die radii are considered as main design parameters. The constructed system for elliptical deep drawing products would be very useful to reduce lead time and improve accuracy for production.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.265-271
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• 2011

기존의 재래식, 전단, 튜브 스피닝은 모두 축대칭 제품의 형상화된 맨드릴을 사용하여 가공하여 왔다. 이러한 고전적 기법에서 한걸음 더 나아가 비축대칭, 열처리를 동반한 스피닝, 자유 맨드릴 공법이 시도되고 있다. 본 조사에서는 비대칭 스피닝과 열처리 스피닝에 등에 대한 신기술 동향과 자유 맨드릴을 사용하는 스피닝 기술 동향을 조사하였다.