• 대한기계학회논문집A
• /
• 제30권2호
• /
• pp.157-163
• /
• 2006

Our research dealt with micro fabrication using micro forming process. The goal of the research was to establish the limit of forming process concerning the size of forming material and formed shape. Flat-rolled ultra thin metallic foils of pure copper(3.0 and $1.0{\mu}m$ in thickness)and stainless steel($2.5{\mu}m$ in thickness) were used for forming material. We obtained the various shapes of micro channels as using designed forming process. $12-14{\mu}m$ wide and $9{\mu}m$ deep channels were made on $3.0{\mu}m$ thick foil and $6{\mu}m$ wide and $3{\mu}m$deep channels were made on $1.0{\mu}m$ thick foil. Si wafer die for forming was fabricated by using etching technique. And the relation of etching time and die dimension was investigated for fabricating precisely die groove. For the forming, die and metal foil were vacuum packed and the forming was conducted with a cold isostatic press. The formed channels were examined in terms of their dimension, surface qualities and potential for defects. Base on the examinations, formability of ultra thin metallic foil was also discussed. Finally, we compared the forming result with simulation. The result of research showed that metal forming technology is promising to produce micro parts.

• 소성∙가공
• /
• 제7권3호
• /
• pp.207-214
• /
• 1998

Influence of final thickness distribution in superplastic forming processes on mechanical properties of the product becomes very crucial. We should improve the thickness distribution of products by combining process parameters adequately In this paper we adopt a non-linear optimization technique for optimal process design of superplastic forming. And optimum design variable which makes the most adequate thickness distribution in combined stretc/blow forming and blow forming is predicted by this optimization scheme and rigid-viscoplastic finite element method.

• 한국기계가공학회지
• /
• 제10권5호
• /
• pp.72-78
• /
• 2011

Currently, for the damper case, the material produced by cast/forge welding is mechanically processed and then the final product is mass-produced. By cutting the cast/forge welded material, the issues of excessive cutting time, multiple process production, and a large amount of chips (40% loss from the original material) arise, causing increased production cost and reduced profitability. Thus, in this study, the incremental forming technology which generates no chips was applied in production. Analysis was excuted for 1st and 2nd works by change of tool diameter and working tool. For this, 3D molding and analysis were executed, which was applied to the processing the result, successful processing could be achieved through a few trials of molding processing according to tool forming and rotation counts.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1994년도 박판성형기술의 진보
• /
• pp.1-9
• /
• 1994

Three recent developments made at Rensselaer in sheet material forming processes are briefly reviewed in this paper. These advances represent three broad disciplines of Process Simulation, Forming Processes, and Computer-Aided Measurement Methods. The first development deals with simple and quick computer simulation of 2D sheet forming process without depending on popular finite element analysis methods. An analytical method based on a thin shell theory accounts for bending and unbending effects, and is capable of simulating practical sheet metal forming processes under the plane strain condition. The second area is concerned with innovative methods to improve formability of sheet materials by temperature gradient forming. The drawing limit is increased by such an improved temperature gradient forming process. The third and final area deals with a totally new experimental technique to capture 3D geometry data and measure strain distributions of sheet metal parts using a digital 35mm SLR camera.

• 한국세라믹학회지
• /
• 제31권1호
• /
• pp.31-38
• /
• 1994

To overcome the demerit of conventional forming method, new forming method, pressureless powder packing forming method, was investigated. This technique is performed by powder packing followed by the infiltration of binder solution. Various alumina powders were used as starting materials and the powders showing good packing condition through powder packing experiment were chosen. The green densities prepared by this new forming method with these powders were lower than those of specimens by pressing method, but, nearly same density was obtained in case of green body prepared with the powders having high packing density. The distribution of binder in a green body was homogeneous and it was possible to a complex shape form by this forming method.

• 한국CDE학회논문집
• /
• 제17권3호
• /
• pp.188-197
• /
• 2012

Recently, aluminum ships are constructed more than ever because of the environmental pollution generated by FRP (Fiber Reinforced Plastic) ships. In particular, FRP ships have been replaced by the Aluminum ships. The forming process of the curved aluminum plate has been performed only by labor works without systematic technique. Therefore, it is difficult to construct the aluminum ship that the design satisfies both required propulsion performance and hull design. Present study introduces a MPSF (Multi Point Stretching Forming) that is a flexible manufacturing technique to form large sheet panels of doubly curvature. The hull pieces are stretch-formed over the MPSD (multi-point stretching die) generated by the punch element matrix. In this study, MPSF is applied to deform the doubly curved surfaces of aluminum ship. The forming system including FEA (finite element analysis) of the processes for stretching the plate were carried out by static implicit analysis is suggested. Residual deformation of the surface is modeled by an elasto-plastic contact phenomena while the forming process is simulated by FEA. Finally, the proposed system is also validated, comparing the deformed shape by MPSF with that of object surfaces.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 추계학술대회논문집
• /
• pp.229-232
• /
• 2003

In the roll forming process, a sheet or strip of metal is continuously and progressively formed into a desired cross-sectional profile by feeding it through a series of forming roll. Accordingly, it is important to maintain the material properties of the initial sheet and deform uniformly during the roll forming. The roll forming process was estimated in consideration of some factors such as material properties, strip thickness, roll diameter, roll velocity, and the deformation of the material that influence the forming length. The hydroforming technology has been recognized as a new technique in manufacturing industry, especially in automotive industry. The formed pipe in used in hydroforming process is manufactured by the roll forming. The formability during hydroforming is very sensitive to the state of pipes which are made by roll forming. Particularly the amount of hardening during roll forming affects the formability. Therefore, it is necessary to design the optimum roll flower to reduce the local hardening. In this paper, optimum roll flower which has uniform strain distribution through sheet width was obtained by comparing strain distribution in various roll flower. Finite element analysis(FEA) is performed to estimate the strain distribution related to hardening by roll forming. A numerical analysis is carried out by SHAPE-RF.

• 한국추진공학회지
• /
• 제11권1호
• /
• pp.27-33
• /
• 2007

각이 있는 얇은 콘 제품을 생산하기 위한 가공법으로는 전단 스피닝에 의한 성형방법이 많이 이용되고 있으며 이는 다른 가공방법에 비해 성형에 필요한 힘이 적게 들고 전단 스피닝에 의해 가공된 제품의 기계적인 강도가 우수하며 표면 품질이 우수하기 때문이다. 따라서 전단 스피닝 기술은 산업현장에서 폭 넓게 이용되고 있다. 특히 전단 스피닝과 유동성형은 자동차, 항공, 방위산업에 자주 이용되고 있다. 본 논문에서는 전단 스피닝에 대한 유한요소해석을 통해 가공깊이와 롤의 리드각이 성형력에 미치는 영향을 살펴보았다. 다양한 가공깊이와 롤의 리드각 조건에서 축 및 반경방향의 성형력을 구하였다.

• 소성∙가공
• /
• 제11권5호
• /
• pp.430-438
• /
• 2002

This paper suggests the new technology to control metal flow in orther to change of the cold forging from conventional deep drawing forming. This technology can be summarized the complex forming, which consists of bulk forming and sheet forming, and multi-action forging, which be performed double action press. The proposed technology is applied to hub clutch model which is part of auto-transmission for automobile. The purpose of this study is to investigate the material flow behavior of hub clutch through control the relative velocity ratio and the stroke of mandrel and punch using the flow forming technique. First of all, the finite element simulations are applied to analyse optimal process conditions to prevent flow defect(necking defect etc.) from non-uniform metal flow, then the results are compared with the plasticine model material experiments. The punch load for real material is predict from similarity law. Finally, the model material experiment results are in good agreement with the FE simulation ones.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 추계학술대회논문집
• /
• pp.97-100
• /
• 2003

Globally, the various machine components, as in electronics and communications, are demanded to being high-performance and micro-scale with abrupt development of the fields of computers, mobile communications. As this current tendency, production of the parts that must have high accuracy, so called milli-structure, are accomplished by the method of top-down, differently as in the techniques of MEMS, NANO. But, in the case of milli-structure, production procedure is highly costs, difficult and demands more accurate dimension than the conservative forming, processing technique. In this paper, forming analysis of the micro-former as the milli-structure are performed and then calculate the punch force etc. This information calculated is applied to decide the forming capacity of micro-former and design the process of forming stage, dimension of dies in another forming bodies. And, for the better precise forming analysis, elasto-plastic analysis is to be performed, then the consideration about effect of elastic recovery when punch and die are unloaded, have to be discussed in change of dimensions.