• 소성∙가공
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• 제11권8호
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• pp.676-681
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• 2002

The square cup deep drawing simulations for hydraulic counter pressure deep drawing are carried out by the finite element method and the formability factors which affect to the formability in case of that process are investigated. As a result, it is found that the thickness distributions keep the higher quality than that of the conventional deep drawing, and the maximum pressure increased the thickness at the die profile regions of blank. But friction coefficient decreased the thickness at the same regions.

• 대한기계학회논문집A
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• 제37권7호
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• pp.865-873
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• 2013

CNG 압력용기의 제조를 위하여 고성능 수평식 프레스를 이용한 딥드로잉과 아이어닝의 연속공정(D.D.I. 공정)이 도입되었다. 그러나, 몇몇 D.D.I. 공정 변수들은 현장 경험에 의존하여 결정되는 문제점이 있으며, 다이의 짧은 수명 역시 고성능, 저비용의 압력용기 제조를 위하여 필수적으로 개선되어야 한다. 본 연구에서는, 공정의 신뢰성 확보 및 다이 수명 향상을 위하여 기존 관련 연구 및 현장 경험을 바탕으로 드로잉비, 다이 간의 간격, 드로잉 다이의 라운딩 반경, 아이어닝 다이의 각도를 공정변수로 결정하였다. FEA 를 이용하여 각 성형 단계에서 찢어짐과 주름이 발생하지 않는 한계 드로잉비를 결정하였고, 다이 간의 간격, 드로잉 다이의 라운딩 반경, 아이어닝 다이의 각도에 대하여 실험계획법을 이용하여 최적 공정설계를 수행하였으며, 기존 공정에 의한 결과와 비교하여 효율성을 검증하였다.

• 대한금속재료학회지
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• 제56권12호
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• pp.861-869
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• 2018

To determine the origin of the inhomogeneous microstructure and texture observed in drawn and annealed high purity copper wires, two kinds of drawing process conditions and their influence was investigated. The regular condition, based on a symmetric die, and a condition designed intentionally to produce an inhomogeneous shear deformation using an asymmetric die were employed. The difference in intensity of <111>-<100> distributed texture between the two wires confirmed that the wire drawn under the asymmetric die condition experienced a higher amount of shear deformation. The extensive shear strain in the wire drawn under the asymmetric die condition gave rise to inhomogeneous primary and secondary recrystallization behavior. After annealing at $200^{\circ}C$, grains with <100> texture, which were larger than the surrounding recrystallized grains, were extensively present on one half circle of the wire drawn under the asymmetric die condition, while larger grains with <100> were sparsely observed around the middle region of the wire drawn under the regular condition. Interestingly, the area where the larger grains with <100> texture existed was identical to the area where the high shear strain occurred during drawing in both wires. During annealing at $400^{\circ}C$, grains with <112> texture started to grow abnormally at the center of both wires as a result of secondary recrystallization. After annealing at $900^{\circ}C$ grains with <112> due to secondary recrystallization occupied the entire region of the wire drawn under the regular condition. On the other hand, in the wire drawn under the asymmetric die condition and then annealed at $900^{\circ}C$, the <100> oriented grains as a result of the normal grain growth of the larger <100> grains which were observed after annealing at $200^{\circ}C$, coexisted with the abnormally grown <112> grains. These results indicate that dynamic recrystallization induced by the shear strain during drawing plays an important role in the inhomogeneity of the microstructure and texture of wires after annealing.

• 한국자동차공학회논문집
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• 제24권3호
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• pp.338-344
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• 2016

The study is actively being performed to increase fuel injection pressure of common rail system among countermeasures to meet the emission regulation strengthen of the Diesel engine. The common rail fuel injection tube in such ultra high pressure common rail system has the weakest structural characteristics against vibration that is generated by fuel injection pressure and pulsation during engine operation and driving. Thus the extreme durability is required for common rail fuel injection tube, and the drawing process is being magnified as the most important technical fact for strength of seamless pipe that is the raw material of common rail tube. In this respect, we analyzed the characteristic of dimension and stress variation of the ultra high pressure common rail fuel injection tube by variation of Die and Plug angle in drawing process. Based on the analysis, we tried to obtain the raw material strength of common rail fuel injection tube for applying to the ultra high pressure common rail system. As a result, Plug angle is more important than entry angle of Die and we could obtain the target dimension and strength of the ultra high pressure common rail fuel injection tube through optimization of Plug angle.

• 한국기계가공학회지
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• 제2권2호
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• pp.45-51
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• 2003

The multi-piloting type progressive die for U-bending sheet metal production part is a very specific division. This study reveals the sheet metal forming process with multi-forming die by center carrier type feeding system. Through the FEM simulation by DEFORM, it was accepted to u-bending process as the first performance to design of strip process layout. The next process of die development was studied according to sequence of die development, i.e die structure, machining condition for die making, die materials, heat treatment of partially die components, know-how and so on. The feature of this study is the die development of scrapless progressive die of multi-stage through the modeling on the I-DEAS program, components drawing on the Auto-LISP, CAD/CAM application, ordinary machine tool operating and revision by tryout.

• 소성∙가공
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• 제7권5호
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• pp.439-444
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• 1998

Recently many automotive parts have been made with stainless steels by deep drawing processes, But there are various problems occurred in deep drawing works of stainless steels compared with low carbon steels. For the severe deep drawing of complex cylindrical housing optimum process planning is required to eliminate intermediate annealing improve shape accuracy and maintain surface integrity without drawing defects such as tears wrinkles and scratches or galling. Therefore in this study a sample process planning of the severe of the severe deep drawing process is applied to a complex cylindrical housing needed for a 6 multi-stepped deep drawing of type STS 305 . A series of experiments are performed to investigate optimum process variables such as drawing rate radius and clearance. Through experiments the variations of the thickness strain distribution and hardness distribution in each drawing step are observed. Also the effects of other factors on formability such as drawing oil, blank holding force and die geometry are examined and discussed.

• 소성∙가공
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• 제24권3호
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• pp.155-160
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• 2015

One of the most important aspects in multi-stage shape drawing is the proper design of the intermediate dies especially to provide adequate metal distribution. In the current study, a method for designing the intermediate dies has been developed to manufacture hollow linear motion guide rails by multi-stage shape drawing. The design method is based on the modified virtual die method. The effectiveness of the proposed design method was verified by FE-simulations and experiments using Mn55Cr carbon steel. From the results of the FE-simulations and the experiments, the proposed design method led to a drawn product with a sound shape. The dimensional tolerances of the product were within the allowable specified tolerances.

• Design & Manufacturing
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• 제15권3호
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• pp.13-18
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• 2021

In plate forming technology, cylindrical drawing process is widely used in industry due to technological development. In this study, we used stainless steel 3042B and stainless steel 304J1, which are the most commonly used materials in the production of cold and hot water tanks for water purifiers, among cylindrical drawing products. Under the same conditions, the thickness of the sidewall of the product formed by drawn experiment was studied. As a result of the experiment, the bottom thickness of stainless steel 304J1 was considered to be thick. It is judged that the defect rate can be reduced by changing the breaking phenomenon of the floor surface of the cold and hot water bottles to the material of stainless steel 304j1. Stainless steel 304 2B material shows a sharp change in thickness from punch corner R to sidewall position, while stainless steel 304J1 material showed a uniform change from punch corner R to sidewall position. Stainless steel 304J1 material is considered to improve the clamping of the product in the process of extracting the product after hand drawing. The appearance of stainless steel 3042B products is considered to produce more wrinkles in the flange, which exerts greater tensile force on the sidewall during molding, resulting in uneven sidewall thickness.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 춘계학술대회 논문집
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• pp.71-76
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• 2001

This paper describes a research work of developing system for conceptual die design system for Fine blanking. The method of approaching to the system is based on the knowledge-based rules. Knowledge for the system is formulated from experimental results and the empirical knowledge of field experts. This system has been written in VisualLISP on the AutoCAD using a personal computer and in Microsoft Visual Basic ver.6.0. Transference of data is accomplished by DXF (Drawing Exchange Format) method. This system consists of six modules, which are cognition of a drawing, cognition of shear length, calculation of shear force, materials properties database, determination of degree of difficulty of the product, determination of approximate life of punch and die modules. Results carried out in each module will provide efficiency to the designer and the manufacturer of die for Fine blanking. But the main focus of this system is the design of die for Fine blanking in the level of general concept. In order to use powerful tool in this field, developed system will be studied continuously.

• Design & Manufacturing
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• 제2권3호
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• pp.32-39
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• 2008

after using dom die, this sheet pressed from a variation condition of size, of die holder power,of rpm speed, accordingly the kind of material, the conditionof deformation movement between both sheets is analyzed, is investigated in the Press machine. even if the change quantity which formed raises a blank holder pressure, the change quantity which is special is not visible from the segment where there is not a bead, the segment where there is a bead to the other side does change quantity schedule to initially and the features of press holding power which the change quantity diminishes is showed consequently from pressurization change quantity it is visible but until a rupture territory from the rpm, it goes but the features where the change quantity does not change a lot is observationd, from the CR2-sheet the quality comes out though well but a possibility of getting a result under same conditions of AL-sheet does not become the formation which stands is. It is like that though press-die which uses the drawing-sheet it exchanges the sheets, when AL-sheet with doing, the conclusion for maintain which have a formation sincerity healthy characteristic is same with afterwords.