• 제목/요약/키워드: Forming Defects

검색결과 278건 처리시간 0.019초

유한요소법을 활용한 궤도륜의 프레스 성형공정 설계 (Process Analysis and Design in Forming of Bearing Rings by the FEM)

  • 강범수;이진희;변상규;최한호;김완두
    • 소성∙가공
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    • 제3권2호
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    • pp.189-201
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    • 1994
  • This study aims detecting forming defects for the forming process of bearing rings, which is designed by and industry expert. The designed process consists of one forming operation for the outer ring and four operations for the inner ring. The thickness of the sheet used is 1.6mm, and is in between of thin sheet and bulk material. Here the rigid-plastic finite element method is applied to the analysis and design of the process without considering anisotropy of thin sheet. Thinning and folding defects are detected if the initially designed process is applied for manufacturing. So a new process is designed by referring the results of the FEM. It is confirmed that the industry expert agree the possibility of defects derived from FEM results.

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유한요소법을 활용한 궤도륜의 프레스 성형공정 설계(II) (Process Analysis and Design in Forming of Bearing Rings by the FEM(II))

  • 변상규;김태호;강범수;김완두
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1995년도 춘계학술대회논문집
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    • pp.19-30
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    • 1995
  • The analysis had been already completed to detect forming defects for the forming processes of C/R bearing rings. But some unpredicted problems were found through the experiments. So expert redesigned new forming processes to prevent the problems and new analysis was began according to the new processes to find faults for the processes. The forming processes consist of 1 for the outer ring. 6 inner ring. The thickness of metal sheet used is changed to 1.5mm from 1.6mm. Elasto-plastric finite element method is applied to involve the effect of spring back . The most representative alteration is forming of two predents to assist later forming . Thining and distribution of high residual stress are derived from the results of simulations. It is confirmed that the industry expert agree the possiblilty of defects dervied from the new FEM results.

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다단계 자동차 부품 소성가공 공정설계 (Process Design in Multi-stage Forming of an Automobile Component)

  • 변상규;양순종;제진수;강범수
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1996년도 춘계학술대회논문집
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    • pp.121-129
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    • 1996
  • This study aimsdetecting defects for the forming precesses of X2 spline, which is designed by an industry expert. The exist process consists of 3 runs and 7 operations with 3 heat treatments. The rigid-plastic FEM analysis was carried out to design a new process and some defects were found. Thus the design was modified to get better results. it is ocnfirmed that the industry expert agree the possibility of defects derived from the FEM results.

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폴리우레탄 코팅 장갑의 기포로 인한 불량 현상에 대한 고찰과 개선 (A Study on Defects Due to Air Bubbles in the PU-Coating Gloves and Enhanced Molds to Reduce the Defects)

  • 김용우
    • 한국공작기계학회논문집
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    • 제16권5호
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    • pp.55-62
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    • 2007
  • With the developments in knitting, manufacturing, and polymers, coated gloves have been evolved in a way to maximize occupational safety and functionality. In this paper, we have considered the PU-coating process for the glove knitted by Dyneema to reduce the occurrence of the defects due to air bubble. This paper classifies the types of defect due to air bubble and traces their forming mechanisms. The air between coating layer of glove and mold's surface forms the defects if it is not evacuated fully in the process of submerging into water. The defects can be suppressed or avoided by forming air-evacuating path on the surface of the molds.

내마모계 Al-Si 재료의 레오로지 성형기술 개발 (I);충진거동 및 결함분석 (Development of Rheology Forming Technology of Wear Resistance Al-Si Materials (I);Filling Behavior and Defect Evaluation)

  • 정홍규;강성수;문영훈;강충길
    • 한국주조공학회지
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    • 제20권6호
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    • pp.368-376
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    • 2000
  • Rheology forming technology has been accepted as a new method for fabricating near net shaped products with lightweight aluminum alloys. The rheology forming process consists of reheating process of billet, billet handling, filling into the die cavity and solidification of rheology formed part. The rheology forming experiments are performed with two different die temperatures ($T_d$ = $200^{\circ}C$, $300^{\circ}C$) and orifice gate type. The filling behavior and various defects of Al-Si materials with wear resistance (A357, A390 and ALTHIX 86S) fabricated in rheology forming process are evaluated in terms of alloying elements and surface non-uniformity. Finally, the methods to obtain the rheology formed products with high quality are described by solutions for avoiding the surface and internal defects.

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B.T.Pin을 이용한 치형부품의 측면 냉간성형공법 개발 (Development of Side Forming Technology for the Tooth Part Using B.T.Pin in Cold Forming Process)

  • 이진수;박세제;김병민;김동환
    • 소성∙가공
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    • 제26권2호
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    • pp.95-100
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    • 2017
  • In this study, the method of process design for side forming of a tooth part used for a component of automobile transmission was suggested using FE-simulations. To develop the side forming for the tooth part, in this paper, the shape factors of B.T.Pin was considered as design parameters. The shape factors of B.T.Pin were selected to be the round of pin, reinforced angle and reinforced length. Based on FE simulation results, appropriate shape factor without causing any defects was selected. In addition, to increase the strength of pin, the combination of shape factor having minimum stress after side forming was selected using FE-simulation. In addition, with design of a die set, cold side forming of the tooth part was experimented to estimate effectiveness of the designed B.T.Pin. From experiments, it was found that the tooth part with complete formation of the tooth was obtained without making any forming defects and punch fracture.

자동차용 충격흡수기의 튜브 스피닝 공정 해석

  • 김영호;박재우;조호성
    • 한국정밀공학회지
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    • 제17권3호
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    • pp.33-38
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    • 2000
  • In process of tube spinning far shock absorber on vehicles, the selection of feed rate and rounding radius of forming roller and revolution speed of tube and forming roller, forming gap between die and forming roller are very important factors to obtain the optimal process result. In this paper, rigid-plastic FEM and UBET analysis are applied to verify effect of each factors by forming load. We can obtain the optimal conditions to prevent defects during processing.

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긴 관을 이용한 롱넥플랜지 성형공정 개발에 관한 연구 (A Study on the Forming Process Development of a Long-neck Flange Using a Long Pipe)

  • 최간대;강우진;배원병;조종래
    • 한국정밀공학회지
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    • 제19권8호
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    • pp.212-219
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    • 2002
  • The pipe with a long-neck flange is widely used in power plants, chemical plants, and shipbuilding companies. Now the pipe with a long-neck flange is manufactured by welding a thick flange to a pipe. But this long-neck flange pipe has some defects in the welding region such as unfitting and local thermal fatigue, which weaken the strength around the neck of the flange. Moreover, after welding the flange, the contacting surfaces of the flange have to be machined flat. So, that is uneconomical. Therefore, to solve the above problems of the long-neck flange pipe, a new process, which has no defects around the flange neck, is required. In this study, three forming processes are suggested to get an enhanced long-neck flange. First suggested process consists of conical forming and flange forming. Second and third suggested processes consist of the bulging of a long pipe locally heated by induction coils and the flange forming. The differences between second and third suggestions are the thickness and local heating area of the pipe. That is, the thickness of the initial pipe of third suggestion is larger than that of the final product, and the local heating area is smaller than that of second suggestion. These three suggestions for forming a long-neck flange are simulated by FE analyses with a commercial code DEFORM 2D. Especially, the theoretical result of FE analysis on the first suggestion for forming a long-neck flange is verified by the experiment with aluminum 6063 pipes. From the theoretical and experimental results, it is concluded that three suggested processes are very useful in order to manufacture the pipe with a long-neck flange without any defects.

의사결정이론을 이용한 박판성형공정의 최적화 (Optimization of Sheet Metal Forming Process by using Decision-Making Theory)

  • 김경모;인정제
    • 한국기계가공학회지
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    • 제11권2호
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    • pp.125-136
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    • 2012
  • Wrinkle and fracture are two major defects frequently found in the sheet metal forming process. In this process there are more than one design attributes to optimize and several uncontrollable factors which cannot be ignored in determining the optimal values of design variables. Therefore, attempts to reduce defects through a traditional optimization technique are often led to failures. In this research, a new design method for reducing the wrinkle and fracture under uncontrollable factors is presented by using decision-making theory. To avoid the psychological difficulties in determining the scaling constants of the multi-attribute utility function by using the ordinary lottery questions, a pair-wise comparison procedure is adapted to avoid this problem. The effectiveness of the proposed method is illustrated through a robust design of sheet metal forming process of a side member of an automotive body.

유한요소해석을 이용한 성형 롤 설계 (Design of Forming Rolls using Finite Element Analysis)

  • 김광희
    • 한국해양공학회지
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    • 제13권4호통권35호
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    • pp.75-81
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    • 1999
  • Roll forming process is simulated with a commercial FEM code LS-DYNA. The rolls are treated as rigid bodies rotating with a constant angular velocity. The strip and the rolls are modeled with 4-node plate elements. It is assumed that the nodes along the front end of the strip move along paths given by sine functions. It is found that the analysis can be applied to the optimal design of forming rolls. With these analyses, it is expected that forming defects can be avoided and process development efforts can be reduced.

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