고압 튜브를 위한 전후방 유동성형에서의 성형력에 관한 연구

남경오(Kyoungo Nam),염성호(Sungho Yeom),홍성인(Sungin Hong) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The flow forming, also known as tube spinning, has been used to produce long thin walled tube parts, with reduced forming force and enhanced mechanical and surface quality for a good finished part, compared with other method formed parts. As the tool is applied locally on the workpiece, the total forming forces are reduced significantly compared to other forming method. Spinning and flow forming techniques are used frequently in automotive, aerial, space, defense industry. In flow forming, forward and backward flow forming methods are classified in accordance to their direction of axial flow during the process. For forward flow forming, the material flows in the same direction as that of the traversing rollers. This method is suitable for making high precision thin walled cylinders, such as hydraulic cylinders, high-pressure vessels, launcher tubes and combustion chamber. For backward flow forming, spun material flows under the roller in the opposite direction of the roller towards the unsupported end of the mandrel. In this paper, finite element method analysis of three-roller forward and backward flow forming for high pressure tube is carried out to study effects of forming depth and feed rate on forming force. The axial and radial forming forces of forward flow forming on several forming depth and feed rate conditions are compared with those of backward flow forming.

유동성형의 성형변수가 금속유동에 미치는 영향

남경오,염성호,박현진,홍성인 한국공작기계학회 2006 한국공작기계학회 추계학술대회논문집 Vol.2006 No.-

The flow forming has been used to produce long thin walled tube parts, with reduced forming force and enhanced mechanical and surface quality for a good finished part, compared with other method formed parts. Therefore, spinning and flow forming techniques are used frequently in automotive, aerial, defense industry. Forming parameters effecting metal flow in the flow forming are lead angle, feed rate, thickness reduction ratio, mandrel revolution and material property etc. Especially, lead angle and feed rate of the working roller are important parameters for the formed metal flow. In this paper, finite element method analysis of one-roller two-path backward and forward flow forming is carried out to study effects of lead angle and feed rate on the formed workpiece geometry. Various lead angles and feed rates are applied in flow forming process analysis. As a result of analysis, build-up, bulging and bell-mouth dimensions on various forming conditions are obtained and compared with each analysis cases.

유동성형의 성형변수가 금속유동에 미치는 영향

남경오(Nam Kyoung O),염성호(Yeom Sung Ho),박현진(Park Hyeon Jin),홍성인(Hong Sung In) 한국생산제조학회 2006 한국공작기계학회 춘계학술대회논문집 Vol.2006 No.-

The flow forming has been used to produce long thin walled tube parts, with reduced forming force and enhanced mechanical and surface quality for a good finished part, compared with other method formed parts. Therefore, spinning and flow forming techniques are used frequently in automotive, aerial, defense industry. Forming parameters effecting metal flow in the flow forming are lead angle, feed rate, thickness reduction ratio, mandrel revolution and material property etc. Especially, lead angle and feed rate of the working roller are important parameters for the formed metal flow. In this paper, finite element method analysis of one-roller two-path backward and forward flow forming is carried out to study effects of lead angle and feed rate on the formed workpiece geometry. Various lead angles and feed rates are applied in flow forming process analysis. As a result of analysis, build-up, bulging and bell-mouth dimensions on various forming conditions are obtained and compared with each analysis cases.

후방유동성형에서 빌드업 생성이 성형력에 미치는 영향

장승용(Jang Seung Yong),박현진(Park Hyun Jin),우호길(Woo Ho Kil),남경오(Nam Kyoung O) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10

The flow forming has been used to produce long thin walled tube parts with reduced forming force and enhanced mechanical and surface quality for a good finished part compared with other method. The forming parameters affecting metal flow and forming force in the flow forming are lead angle, feed rate, thickness reduction ratio, mandrel revolution and material property etc. Especially, lead angle, feed rate of the working roller, build-up and thickness reduction ratio are important parameters for the flow forming. In this paper, one-roller backward flow forming analysis is carried out to study effects of the build-up creation affecting the contact area. The forming force is related to the contact area between roller and workpiece. To calculate accurate contact area and forming force, the geometric method and numerical analysis was proposed in this paper.

플로우포밍 물성확보를 위한 알루미늄 휠 내구시험

신준탁(Jun Tak Shin),유연상(Yeon Sang Yoo),김성겸(Sung Kyeom Kim) 한국자동차공학회 2014 한국자동차공학회 학술대회 및 전시회 Vol.2014 No.11

There are several test modes (CFT, RFT, Impact Test) for aluminum wheel to prove its performance. HMC (Hyundai Motor Company) Chassis CAE Team has been developing wheel analysis which has been correlated with tests. The aluminum wheel material properties(Strength, Durability) which apply to CAE are gotten from specimen tests. Using Flow-Forming Process in manufacturing aluminum wheel is on the increase recently. According to studies and papers, aluminum wheel which apply to Flow-Forming Process has higher mechanical properties(Strength, Durability, Elongation etc.) than aluminum wheel which is not apply to. But, we have not gotten the durability material property in aluminum wheel which apply to Flow-Forming Process. Because, rim of aluminum wheel which apply to Flow-Forming Process is too thin to get the specimen. In this paper, to get the durability material property of aluminum wheel which apply to Flow-Forming Process, we propose the ‘Rim Specimen Test’ instead of common specimen test. From the results of ‘Rim Specimen Test’ and using CAE, we get the durability material property of aluminum wheel apply to Flow-Forming Process. Also, we are able to compare the durability material property of Flow-Forming Process and Non-Flow-Forming Process.

Prediction of the surface roughness of AA6082 flow-formed tubes by design of experiments

M. Srinivasulu,M. Komaraiah,C. S. Krishna Prasada Rao 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.6

Flow forming is a modern, chipless metal forming process that is employed for the production of thin-walled seamless tubes. Experiments are conducted on AA6082 alloy pre-forms to flow form into thin-walled tubes on a CNC flow-forming machine with a single roller. Design of experiments is used to predict the surface roughness of flow-formed tubes. The process parameters selected for this study are the roller axial feed, mandrel speed, and roller radius. A standard response surface methodology (RSM) called the Box–Behnken design is used to perform the experimental runs. The regression model developed by RSM successfully predicts the surface roughness of AA6082 flow-formed tubes within the range of the selected process parameters.

유동성형을 이용한 중공형 부품 제조공정 개발

권용남(Yong-Nam Kwon),김상우(S. W. Kim),김봉준(B. J Kim),박은수(E. S. Park),차달준(D. J. Cha) 한국소성가공학회 2011 한국소성가공학회 학술대회 논문집 Vol.2011 No.5

In the present study, flow forming process for the manufacturing hollow shape transmission component was investigated with both forming experiment and numerical analysis. Flow forming is a kind of incremental forming processes which uses a roller to form a cylindrical part with repeated turning of both roller and sheet. Hollow type parts can be effectively flow-formed with the use of tube as starting material compared to a usual sheet since an average strain accumulation during whole flow forming process is much lower in the case of tube as staring material. However, it is still hard to flow-form high strength steel sheet in a tool path. Therefore, it is quite usual to distribute the amount of thickness reduction or strain into several tool paths. In the present study, optimum processing paths were tried to be sought by both using a series of experiments and numerical analysis. Also, trial sample was examined to verify flow forming process design.

Flow-forming 공법을 이용한 annulus gear 제조 기술 연구

이성민(S. M. Lee),김봉준(B. J. Kim),변원용(W. Y. Beon),김태덕(T. D. Kim),박은수(E. S. Park),권용남(Y. N. Kwon) 한국정밀공학회 2011 한국정밀공학회 학술발표대회 논문집 Vol.2011 No.6월

Conventional automatic transmission system includes a hydrodynamic torque converter to transfer engine torque from an engine crank shaft to a rotatable input members, which are of complex design permitting them to serve several functions. These are clutches or brakes which couple the rotatable input member to member of a planetary gear set. The annulus gear for an automatic transmission is a monolithic gear having a set of gear teeth formed on an inner surface which is coupling with a set of planetary gear. In this study, the flow forming method is applied to the manufacturing of the annulus gear. This cold forming is proper method in order to manufacture dimensionally precise and round hollow components such as annulus gear. By pre-calculated amount of wall thickness reduction, the seamless tube of SAE1026 is compressed above its yield strength, plastically deformed and made to flow In several roll passes. According to this study, the desired geometry of the annulus gear can be achieved when the outer diameter and the thickness of the tube are properly decreased by compressed roll passes and the available material volume is easily forced to flow longitudinally over the shape of mandrel.

운동량 방정식의 대류항 이산화 방법이 다차원 2상 유동 해석에 미치는 영향 분석

박익규(I.K. Park),조형규(H.K. Cho),윤한영(H.Y. Yoon),정재준(J.J. Jeong) 한국전산유체공학회 2009 한국전산유체공학회지 Vol.14 No.3

The non-conservative form of momentum equations is often used for some two-phase flow codes instead of a conservative form because of numerical convenience. Another non-conservative form, so called, a semi-conservative form can improve the numerical solution of these codes maintaining the numerical convenience. It is close to the conservative form but still maintains the feature of the non-conservative form. A semi-conservative form of the momentum equations and a non-conservative form of the momentum equations are implemented in CUPID[l] code. The numerical results of the semi-conservative and the non-conservative forms are compared against analytical solutions and the solutions of the FLUENT code that uses the conservative form. The results clearly showed that the semi-conservative form of the momentum equations provides better solutions than the non-conservative form, especially for heterogeneous two-phase flows.

숏폼 콘텐츠와 추천 시스템의 특성이 중국 이용자의 몰입과 만족에 미치는 영향: 틱톡 영화 서머리 콘텐츠를 중심으로

유예,엄명용,김재범 국제e-비즈니스학회 2023 e-비즈니스 연구 Vol.24 No.4

Research Purpose: The objective of this study is to explore how the characteristics of short-form content and recommendation systems impact the flow experience of users. It further elucidates the causality between the above flow experience and user satisfaction. Research Methods: To evaluate the research model, we collected a total of 226 valid survey responses from Chinese users who had engaged with TikTok movie summary content at least once. The hypotheses were tested using structural equation modeling. Results in Research: Both the characteristics of summary content and the recommendation system significantly influenced the factors indicative of flow: enjoyment, attention, and time distortion. Furthermore, a significant causality was observed between short-form users' flow experience (enjoyment, attention, time distortion) and their satisfaction. Research Conclusion: To induce flow experience and satisfaction in short-form users, efficient implementation of user-centered content strategies and recommendation systems is critical. 숏폼은 최근에 등장한 미디어 형태로, 간결한 구조와 빠른 정보 전달을 중시하는 특징을 지니고 있다. 본 연구의 목적은 숏폼 콘텐츠의 특성과 추천 시스템의 특성이 사용자의 몰입에 미치는 영향을 탐색하는것이다. 또한 몰입경험과 만족 사이의 인과관계를 실증하는 것이다. 연구모형을 검증하기 위하여 틱톡 영화서머리 콘텐츠를 적어도 한 번 이상 이용한 경험이 있는 중국인들을 대상으로 총 226개의 유효한 설문 데이터가 수집되었고, 구조방정식을 활용하여 가설을 검정하였다. 연구결과, 서머리 콘텐츠의 특성과 추천 시스템의특성이 모두 몰입을 대변하는 즐거움, 주의집중, 시간왜곡 요인에 유의한 영향을 미치는 것으로 나타났다. 또한 숏폼 사용자의 몰입경험(즐거움, 주의집중, 시간왜곡)과 만족 사이의 관계는 유의한 인과성을 보이는것으로 나타났다. 결론적으로, 숏폼 사용자의 몰입과 만족을 유도하기 위해서는 사용자 중심의 콘텐츠 전략과추천 시스템의 효율적인 구현이 필수적으로 요구된다. 본 연구는 숏폼 콘텐츠 제작 및 추천 시스템 설계에있어 주요한 시사점을 제공하며, 이를 통해 사용자 중심의 콘텐츠 전략을 더욱 효과적으로 구축하는 데기여할 수 있을 것으로 기대된다.