• Title/Summary/Keyword: Workpiece Materials

검색결과 284건 처리시간 0.023초

열박음을 고려한 이종재 금형의 피로수명 예측에 관한 연구 (A Study on the Prediction of Fatigue Life in Dissimilar Materials Die Considering the Heat Shrink Fit)

  • 여은구;김엽래
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 1999년도 춘계학술대회 논문집
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    • pp.93-98
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    • 1999
  • Generally, the - life of die is limited by fatigue fracture or dimensional inaccuracy originated from wear. In this paper, to predict the fatigue life of the dissimilar materials die, the stress and stxain histories of die can be predicted by the analysis of elasto-plastic finite element neth hod and the elastic analysis of die during the process analysis of workpiece. Using heat shrink fit analysis, initial stress of the k r t die is computed. Also, the stress-life curve of die material can be obtained through experiment. With the above two facts, we propose the analysis method of predicting fatigue life in die. In the proposed model, tlz analysis of elastic-plastic finite element method for material is carried out by using ABAQUS. Surface force resulted from the contacting border of the die and workpiece is tmnsformed into the nodal force of die to implement elastic analysis. Besides, the proposed analysis model of die is applied to the one material and the dissimilar materials extrusion die.

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회전단조에 따른 Inconel 706 합금의 미세조직 및 기계적 특성 분석 (Analysis of Mechanical Properties and Microstructure of Inconel 706 Alloy using Rotary Forging)

  • 김효건;조성우;윤은유;이영선;우영윤
    • 소성∙가공
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    • 제32권3호
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    • pp.145-152
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    • 2023
  • The Inconel 706 alloy is a nickel-based super alloy and requires a large load for hot forging due to its excellent mechanical properties at high temperature. Rotary forging process is an innovative metal forging process where workpiece is gradually deformed by the revolving conical upper die with an inclination angle. This process allows that the workpiece is partially in contact with an upper die during the process so that the press force is considerably lower compared with the conventional upsetting process. In this study, experiments of rotary forging process and conventional upsetting process for cylindrical parts using Inconel 706 where conducted to investigate the formability of rotary forging process. And microstructure analysis and mechanical properties of Inconel 706 were performed to investigate the effect of rotary forging process on the material property.

Characteristics of Si3N4 Laser Assisted Machining according to the Laser Power and Feed Rate

  • Kim, Jong-Do;Lee, Su-Jin;Suh, Jeong
    • Journal of Advanced Marine Engineering and Technology
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    • 제34권7호
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    • pp.963-970
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    • 2010
  • This study makes an estimate of the laser-assisted machining (LAM) of an economically viable process for manufacturing precision silicon nitride ceramic parts using a high-power diode laser (HPDL). The surface is locally heated by an intense laser source prior to material removal, and the resulting softening and damage of the workpiece surface simplify the machining of the ceramics. The most important advantage of LAM is its ability to produce much better workpiece surface quality compared to conventional machining. Also important are its larger material removal rates and longer tool life. The cutting force and surface temperature were measured on-line using a pyrometer and a dynamometer, respectively. Tool wear, chips and the surface of the workpiece were measured using optical microscopy, and the surface and fractured cross-section of $Si_3N_4$ were measured by SEM. During the LAM process, the cutting force and tool wear were reduced and oxidation of the machined surface was increased according to the increase in the laser power. Moreover, the more the feed rate increased, the more the cutting force and tool wear increased.

보스-리브 시험 시 마찰보정선도에 대한 펀치형상 및 유동응력의 영향 (Effect of Punch Design and Flow Stress on Frictional Calibration Curve in Boss and Rib Test)

  • 윤여웅;강성훈;이영선;김병민
    • 소성∙가공
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    • 제18권8호
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    • pp.640-645
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    • 2009
  • Recently, boss and rib test based on backward extrusion process was proposed to quantitatively evaluate the interfacial friction condition in bulk forming process. In this test, the tube-shaped punch with hole pressurizes the workpiece so that the boss and rib are formed along the hole and outer surface of the punch. It was experimentally and numerically revealed that the height of boss is higher than that of the rib under the severe friction condition. This work is focused on the effect of the punch design and flow stress on deformation pattern in boss and rib test. From the boss and rib test simulations, it was found that there is slight variation in both the heights of boss and rib according to the length of punch land, nose radius, and face angle. However the hole diameter of the punch and the clearance between the punch and die have a significant influence on the calibration curves showing the heights of the boss and rib. In addition, the effect of flow stress on the calibration curves was investigated through FE simulations. It was found that there is no effect of strength coefficient of the workpiece on the calibration curves for estimation of friction condition. On the other hand, the strain-hardening exponent of the workpiece has a significant influence on the calibration curve.

공작물 재질에 따른 세미드라이 절삭가공 특성 (Semidry-cutting Characteristics according to Workpiece Materials)

  • 이종항;박철우;이석우;최헌종
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.968-973
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    • 2003
  • As environmental restrictions have continuously become more strict, it has emphasized development of environment-friendly technologies. In cutting technology, it has been well recognized that cutting fluids might have undesirable effects on worker's health and working environment and, hence, recently there have been numerous attempts to minimize harmful effects of cutting fluids on environments. To minimize the use of cutting fluids in machining, conventional cutting fluids have been replaced with the technologies of pressurized cold air and minimum quantity lubrication(MQL). Compared with milling, turning is a continuous cutting process, where tools are continuously heated up and lack of lubricity could lead to tool wear and deteriorated surface roughness. In this study, it has been investigated how tool wear and surface roughness could be affected by cutting conditions, supply and cooling methods. The experimental results show that MQL technology is able to minimize harmful effects of conventional cutting fluids.

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와이어 컷 방전가공이 효율적인 NC 모의가공 시스템의 개발 (On the Development of NC Simulator System for Wire Cut EDM)

  • 유우식;김남웅;유정호
    • 대한안전경영과학회지
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    • 제6권1호
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    • pp.283-300
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    • 2004
  • This paper describes the NC simulator system for Wire-cut electrodischarge machining. Electrodischarge Wire-cut machining is applicable to all materials including metals, alloys, and most carbides. Although CAM system generate the NC code considering electrodischarge conditions, incorrect Wire-cut tool path bring about fatal results. The simplest way of simulating a EDM process is to display the trajectory of Wire-cutter location by line segments. With this kind of simulation, the programmer can get a general idea about whether the wire is moving as planned but cannot locate gouging or excess material because only the wire location will be seen, not the changes in the workpiece as it is machined. The ideal way of simulating the EDM process is to display the solid model of the workpiece as it is machined. Therefore we propose the ideal NC simulator system for Wire-cut EDM.

초음파 가공에 의한 미세 에어홀 가공 기술 (Micro-machining of Glass Air Hole using Ultrasonic Machining)

  • 김병희;전성건;남권선;김헌영;전병희
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2004년도 춘계학술대회 논문집
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    • pp.48-52
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    • 2004
  • Ultrasonic machining is effective for machining of extreme hard and brittle materials, including glass, ceramic, carbide, graphite. The major machining principle involves the direct hammering as well as the impact of abrasive panicles on the workpiece. Also, it involve cavitation erosion. The general workpiece is flat side. This study attempted micro hole machining of a curved surface of glass tube. Ultrasonic machining is fault of the slow machining speed. An experiment does and got 16 seconds validity machining time as increasing the processing speed. Moreover, entrance crack and surface roughness was similar both machining speed is slow and fast. Several micro hole of glass tube machined using one micro tool, but tool wear is infinitesimal.

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레이저보조가공에서 중첩열원에 관한 해석 연구 (Analysis of Overlapping Heat Zones in Laser-Assisted Machining)

  • 백종태;이춘만
    • 한국정밀공학회지
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    • 제32권12호
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    • pp.1023-1029
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    • 2015
  • Laser-assisted machining (LAM) is one of the most effective methods for enhancing the machinability of difficult-to-cut materials, such as titanium alloys and various ceramics, and has been studied by many researchers. LAM is a method that facilitates machining by softening a workpiece using a laser heat source. The advantages of the LAM process are decreases in tool wear, cutting force, and surface roughness. However, when the material is over-heated, melting or burning can occur. This study analyzed the heat source distribution with regard to overlapping of preheating on the laser heating path with an acute angle, a right angle and obtuse angles. Then, a power reduction method was proposed to reduce the melting and burning of the workpiece.

볼과 소켓의 정밀 체결을 위한 회전성형 장치 (Rotary Forming Equipment for Precision Joining of the Ball and the Socket)

  • 전병윤;엄재근;전만수
    • 소성∙가공
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    • 제16권2호
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    • pp.132-137
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    • 2007
  • A double roll rotary forming equipment is presented in this paper. The equipment is developed for joining the socket with the ball of a concave piston assembly with its geometrical tolerance requirements satisfied. The equipment is composed of a lathe, a double roll system and a roll pressing unit driven by the hydraulic system. The workpiece rotates by spindle chuck of the lathe while the double roll system approaches perpendicularly to the central line of the workpiece. The equipment is successfully applied to precision joining of the ball and the socket fur the concave piston assembly of a high pressure hydraulic pump.

튜브 스웨이징 공정의 유한요소해석 (Finite Element Analysis of Tube Swaging)

  • 김민철;엄재근;임성주;최호준;전만수
    • 소성∙가공
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    • 제21권3호
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    • pp.160-163
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    • 2012
  • In this paper, a new approach to finite element analysis for tube swaging is presented. An analysis model is developed with emphasis on the pusher that imposes back pressure in order to keep the workpiece from slipping along the die-workpiece interface especially when tapered dies are used. A rigid-plastic finite element method is employed. The approach is to simulate the tube swaging process and the results are compared quantitatively with predictions, showing close agreement with each other.