• 한국정밀공학회지
• /
• 제15권5호
• /
• pp.167-175
• /
• 1998

A mathematical formulation is presented to model anisotropy from the deformation textures developed in a forming process. In this work, a micro-mechanical-based polycrystalline analysis is implemented into a consistent finite element method for the anisotropic, viscoplastic deformation of polycrystalline metals. As suggested by Taylor, the deformation of each grain in an aggregate is assumed to be same as the macroscopic deformation of an aggregate or a macro-continuum point. Algorithms are developed to represent the plastic anisotropy, such as the anisotropic yield surface and R-value, from the predicted deformation texture. As applications, the evolution of texture in rolling, upsetting and drawing/extrusion processes are simulated and the corresponding changes of mechanical properties such as yield surface and R-value are predicted.

• International Journal of Precision Engineering and Manufacturing
• /
• 제9권3호
• /
• pp.75-78
• /
• 2008

Tire molds are manufactured by aluminum casting, direct five-axis machining, and electric discharging machining. Master models made of chemical wood are necessary if aluminum casting is used. They are designed with a three-dimensional computer-aided design system and milled by a five-axis machine. In this paper, a method for generating and machining a tire surface model is proposed and demonstrated. The groove surfaces, which are the main feature of the tire model, are created using a parametric design concept. An automatically programmed tool-like descriptive language is presented to implement the parametric design. Various groove geometries can be created by changing variables. For convenience, groove surfaces and raw cutter location (CL) data are generated in two-dimensional drawing space. The CL data are mapped to the tread surface to obtain five-axis CL data to machine the master model. The proposed method was tested by actual milling using the five-axis control machine. The results demonstrate that the method is useful for manufacturing a tire mold.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1998년도 제2회 박판성형심포지엄 논문집 박판성형기술의 현재와 미래
• /
• pp.171-182
• /
• 1998

An automated surface-strain measuring system using the image processing technique is developed in the present study, which consists of the hardware to capture and to display digital images, and the software to calculate the 3D informations of grid points from two views. New or improved algorithms the mapping and establishing correspondence of grid points and elements, the camera calibration, and the subpixel measurement of grid points, are implemented. As an application of the present system the surface-strains of deformed blanks in the limitting dome height test, the square cup deep-drawing and punch stretching to obtain the forming limit diagram are measured. The results are compared with those obtained by conventional manual methods.

• 한국주조공학회지
• /
• 제22권5호
• /
• pp.265-270
• /
• 2002

A novel jewelry master pattern manufacturing process which reduce manufacturing steps by employing a Duraform rapid prototyping mold and a low melting alloy has been suggested. The novel process follows the steps of 'jewelry 3D CAD design ${\rightarrow}$ Durafrom RP mold ${\rightarrow}$ low melting alloy master pattern' while the previous process follows more complicated steps of 'jewelry idea sketch ${\rightarrow}$ detailed drawing ${\rightarrow}$ wax carving ${\rightarrow}$ flask ${\rightarrow}$ silver master pattern.' An upper and a lower part of molds have been manufactured of Duraform powder, of which melting point is $190^{\circ}C$. A maser pattern was manufactured by pouring a low melting alloy of Pb-Sn-Bi-Cd, so called Woods Metal, of which melting point is $70^{\circ}C$, into the mold. The master pattern is a shape of a disk of 20mm diameter that contains various design factors. The variations of dimensions, surface roughness, surface pore ratio were measured by an optical microscope, a surface roughness profilometer, and a Rockwell hardness tester. The pattern made of were maeasured by an optical microscope, a surface roughness profilometer, and a Rockwell hardness tester. The pattern made of low melting alloy has sufficient surface hardness, and surface pore ratio to be used as the jewelry master pattern.

• 한국지리정보학회지
• /
• 제27권1호
• /
• pp.1-11
• /
• 2024

현재 측정되는 많은 데이터가 지표를 기반으로 측정되지만, 측정지점의 높이값이 기초자료로 활용되지 않기 때문에, 3차원 지리정보시스템에 활용하고자 할 때 어려움이 발생한다. 지표면에 많은 양을 표시하기 위해서는 지형정보를 이용하여 지표면에 점을 그리거나, 지표면의 각 측정지점의 높이값을 추출하여 다각형을 생성하는 방법이 다양하게 사용될 수 있다. 본 연구에서는 다양한 형태의 데이터 표현 방법 중 지표면에 표현되는 시계열 측정 데이터의 시각화 성능을 향상시키기 위한 데이터 구축 및 표시 방법을 시도하고, 그 절차와 장단점을 살펴본다.

• 한국세라믹학회지
• /
• 제29권7호
• /
• pp.544-550
• /
• 1992

Zirconia gel fibers could be made by drawing from polyester sol containing zirconyl oxychloride during the reaction between ethylen glycol and citric acid. In this case, the critical mole ratio of zirconyl oxychloride to citric acid was about 4 and by adding CaCl2 and calcining the gel fiber in the air, cubic stabilized zirconia fibers having much micropores at surface could be obtained.

• 산업공학
• /
• 제9권2호
• /
• pp.129-141
• /
• 1996

Recently, the tire mold of a passenger car is made almost via aluminum casting, and it is necessary to prepare a master model of the tire for the casting. Because of the geometrical feature of tire, as well known, the master model must be machined by a 5-axis NC machine. The paper proposes a procedure to model and machine the master model. The approach includes (a) transformation of 2D drawing of tire into 3D geometry, (b) modeling surfaces of tire, and (c) inverse kinematics of a 5-axis NC machine. An implementation of the proposed procedure is also presented.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
• /
• pp.704-706
• /
• 1991

In CAD/CAM system, many efforts are made to automate the converting process from drawling information to manufacturing Information. The most difficult step In this procedure is utilizing 2 dimensional drawing information In order to formulate 3 dimensional w&ling information. This paper emphasizes to mWe automatically series of convertirg steps which provide 3 dimensional wire frame, surface and solid modeling using feature recognition rules. With the standardization of design process and the recognition rule as preceding steps, it shows a good application tool to interface the design and manufacturing procedures in PC-Level CAD/CAM system.

• 항공우주정책ㆍ법학회지
• /
• 제16권
• /
• pp.65-74
• /
• 2002

The Japanese Aviation Accident Investigation Board has two faces. While the surface of the Board is a one of the very accident investigation organ, its shadow face is a one of the very expert witness drawing up a requested written opinion for the sake of the criminal investigation of the Police under the two secret inter-ministerial accords. This Paper proposes that some evidence obtained by investigation ought to be protected for disclosure and use by privilege derived from on of our most basic legal principles: "Nemo debet se-ipsem accusare-no one is required to incriminate oneself-".

• 복식문화연구
• /
• 제14권3호
• /
• pp.434-442
• /
• 2006

The purpose of this study was to develop the beautiful basic bodice pattern that satisfied both functionality and aesthetics on the basis of the change in the figure and length of surface body for each movement through a three-dimensional development figure of surface body for young women (aged between 18 and 24) who were very sensitive to fitness of clothes. Existing three basic bodice patterns (Yim wonja-, ESMOD-, and FIT-types) were selected and then compared and analyzed in terms of drawing methods and the wearing test was carried out by a sensory test in order to design an experimental prototype. The design of study prototype was improved by three wearing test that was correlated with low satisfactory item. And the ease was established by difference of previous direct measurement and body surface measurement.