• Title/Summary/Keyword: Piercing

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Measurement and Effective Deburring for the Micro Burrs in Piercing Operation

  • Ko, Sung-Lim
    • International Journal of Precision Engineering and Manufacturing
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    • v.1 no.1
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    • pp.152-159
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    • 2000
  • In piercing operation for small hole in very thin plate, micro burrs are formed. The micro burr is very difficult to remove because the thin plate is to be deformed during deburring and deteriorate accuracy. As a first step to remove the micro burrs effectively, the burr must be measured accurately as much as possible. For most micro burrs are so small as less than 10$\mu\textrm{m}$, it is very difficult to measure. Several methods are reviewed to measure the micro burr formed in piercing operation from very thin plate with thickness less than 0.1mm. Also the effective deburring methods are reviewed. Barreling ultrasonic and chemical deburring methods are performed and the results are compared.

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Design of self-piercing rivet to joint in advanced high strength steel and aluminium alloy sheets (초고장력강과 알루미늄 합금의 접합을 위한 SPR 설계)

  • Kim, Dongbum;Qiu, Yuangen;Cho, Hae-Yong
    • Journal of Welding and Joining
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    • v.33 no.3
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    • pp.75-80
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    • 2015
  • Self-piercing riveting is an joining method of advanced high strength steels (AHSS) and other dissimilar materials. It has attracted considerable interest from the automotive industry. The SPR has become an interesting alternative joining technique for difficult to weld materials such as steels and aluminium alloys. In this paper, self-piercing rivet and anvil for SPR were designed for the joining conditions with AHSS and aluminium alloy. Various conditions of SPR were simulated for the design of rivets and anvils. The simulated results were in good agreement with experimental ones. As a result, over HV500 rivet is desirable to joint SPFC780 AHSS and aluminum alloy.

Analysis on Roll Over in the Tube Hydro-Piercing Process (튜브 하이드로 피어싱시 롤 오버의 실험적 분석)

  • Choi, Sung-Ki;Ahn, Ick-Tae;Moon, Young-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.7
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    • pp.992-998
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    • 2004
  • During the tube hydropiercing, the region adjacent to the pierced hole will be deformed and will be drawn away from the die block as the punch advances through the wall of the tube. The deformation in the region may range from a substantially flat form to a countersunk form, so called rollover. In this study, the effects of material properties, shape of piercing punches, roundness of tube surface and internal pressure within the tube during piercing on the rollover have been investigated experimentally. The results provide the quantitative variation of rollover at given hydropiercing parameters, and a relationship between the deformed radius and the rollover caused by the deformation has been established.

Analysis of Deformation Surrounding the Pierced Hole in the Tube Hydro-Piercing Process (하이드로 피어싱된 튜브 부위의 변형해석)

  • 최성기;김동규;문영훈
    • Transactions of Materials Processing
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    • v.13 no.2
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    • pp.154-159
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    • 2004
  • Deformation surrounding the hole in the tube during the hydropiercing process has been investigated in this study. The tube is expanded and internally pressurized between upper and lower dies, and a piercing punch is driven forcefully through a cross passage in the die and through the wall of the tube. The pressurized fluid within the tube provides support to the wall of the tube during a piercing step to form a hole in the tube having less deformation surrounding the hole in the tube. The deformation area may be fully retracted to a substantially flat form or partially retracted to a countersunk form. In this study, a mathematical model that can predict deformation surrounding the hole has been proposed and experimentally verified by actual hydropiercing test.

Rigid-Viscoplastic Finite Element Analysis of Piercing Process in Automatic Simulation of Multi-Stage Forging Processes (다단 단조공정의 자동 시뮬레이션 중 피어싱 공정의 강점소성 유한요소해석)

  • 이석원;최대영;전만수
    • Transactions of Materials Processing
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    • v.8 no.2
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    • pp.216-221
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    • 1999
  • In this paper, an application-oriented approach to piercing analysis in automatic forging simulation by the rigid-viscoplastic finite element mehtod is presented. In the presented approach, the accumulated damage is traced and the piercing instant is determined when the accumulated damage reaches the critical damage value. A method of obtaining the critical damage value by comparing the tensile test result with the analysis one is given. The presented approach is verified by experiments and applied to automatic simulation of a sequence of 6-stage forging processes.

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Finite Element Analysis of a Roll Piercing Process Equipped with Diecher's Guiding Discs (원형디스크 지지 방식의 롤피어싱 공정의 유한요소해석)

  • Shim, S.H.;Cho, J.M.;Lee, M.C.;Joun, M.S.
    • Transactions of Materials Processing
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    • v.21 no.1
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    • pp.19-23
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    • 2012
  • In this paper, a Mannesmann roll piercing process equipped with Diecher's guiding discs is investigated using a rigid-thermoviscoplastic finite elements method with intelligent remeshing capability and tetrahedral elements. The analysis model is presented and the approach is applied to a Mannesmann roll piercing process found in the literature. Details about the remeshing criterion as well as mesh density control are given. The present predictions are compared with the predictions found in the literature, showing that the two predictions are in close agreement in terms of the deformed shape. However, it is emphasized that the present approach has the distinct strength in predicting details of final shape.

A Study on Tensile Shear Characteristics of Dissimilar Joining Between Pre-coated Automotive Metal Sheets and Galvanized Steels with the Self-Piercing Rivet and Hybrid Joining (Self-Piercing Rivet과 Hybrid Joining을 이용한 자동차용 선도장 칼라강판과 용융아연도금강판의 접합부 기계적 성질 평가)

  • Bae, Jin-Hee;Kim, Jae-Won;Choi, Ildong;Nam, Dae-Geun;Kim, Jun-Ki;Park, Yeong-Do
    • Journal of Welding and Joining
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    • v.34 no.1
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    • pp.59-67
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    • 2016
  • The automotive manufactures increase their use of lightweight materials to improve fuel economy and energy usage has a significant influence on the choice of developing materials. To meet this requirements manufacturers are replacing individual body parts with lightweight metals, for these the process treating and painting surfaces is changing. The pre-coated steels are newly developed to avoid the conventional complex and non-environmental painting process in the body-in-white car manufacturing. The development of new joining techniques is critically needed for pre-coated steel sheets, which are electrically non-conductive materials. In the present study, dissimilar combination of pre-coated steel and galvanized steel sheets were joined by the self-piercing rivet, adhesive bonding and hybrid joining techniques. The tensile shear test and free falling high speed crash test were conducted to evaluate the mechanical properties of the joints. The highest tensile peak load with large deformation was observed for the hybrid joining process which has attained 48% higher than the self-piercing rivet. Moreover, the hybrid and adhesive joints were observed better strain energy compared to self-piercing rivet. The fractography analyses were revealed that the mixed mode of cohesive and interfacial fracture for both the hybrid and adhesive bonding joints.

A Model Test Study on the Effect of the Stern Interceptor for the Reduction of the Resistance and Trim Angle for Wave-piercing Hulls (파랑관통형 선형의 저항 및 트림각 감소를 위한 선미 인터셉터 부착효과에 관한 모형시험 연구)

  • Kim, Dae Hyuk;Seo, Inn-Duk;Rhee, Key-Pyo;Kim, Nakwan;Ahn, Jin-Hyung
    • Journal of the Society of Naval Architects of Korea
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    • v.52 no.6
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    • pp.485-493
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    • 2015
  • Planing hull form is widely used as a high speed vessel hull. There is a problem of the planing hull not solved yet. The problem is that the planing hull has very large vertical acceleration and large heave and pitch motions. As one method for overcoming this problem, there is "wave-piercing hull". Before the motion in waves is investigated, the resistance and running attitude must be investigated. In this paper, the running attitude and resistance of two wave-piercing hulls are investigated by model tests. Model test results show that the wave-piercing hulls have large trim angle and sinkage at the high speed, so additional model tests are conducted by using the hull appended by stern interceptor that is very thin plate to increase the hydrodynamic pressure at the attached location. The results are compared with other planing hulls and the resistance components and the hydrodynamic force are discussed. From the model test results, it can be known that the stern interceptor is the effective appendage for the reduction of the resistance and trim angle of wave-piercing hull.

Fruit Piercing Moths Collected at an Orcgard Surrounded by forest in Gyeongnam Province (경남 산지 과수원에서 채집된 과실 흡수나방의 종류)

  • 박정규;신원교;김인곤;김창효
    • Korean journal of applied entomology
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    • v.27 no.2
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    • pp.111-116
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    • 1988
  • Fruit piercing moths were collected at every other at orchaed(16.5ha) planted with plum, peach and pear, and surrounded by forest in Gyeongnam province from jun to September in 1987. Four black light (BL) traps were lightened to attract the moths from sunset to sunrise and sweep net was also used to catch the moths on fruit and around fruit trees from 22 to 23 o'clock, 20 minutes per fruit tree species. Forty-one species, including 15 primary piercing species(PPS) and 22 secondary piercing species (SPS), from 3 families were collected and identified as fruit piercing moths. Among them, 16 species are newly recorded as fruit piercing moths in Korea. O. emarginata, L. juno, P. stuposa, C. lata and O. excavata were diminant species of PPS, comprising 86.7% of the whole PPS. Dominant species of SPS were A. ipsilon, M. turca, S. retorata, A. livida and T. oldenlandiae, comprising 80.5% of the whole SPS. The ratios of PPS to the whole fruit piercing moths collected by BL traps and net were sweep 15.2% and 79.7%, repectively. By sweep net L. juno, P. stuposa, and O. emarginata was also captured in a large numbers on peach, C. lata was on plum, and S. retorata was on pear.

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