• 제목/요약/키워드: Tool shapes

검색결과 345건 처리시간 0.022초

Prevention of Crack Formation by Changing Tool Shapes in Powder Compaction Process

  • Pang, Y.C.;Lee, H.C.
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.30-31
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    • 2006
  • In a multi-action tooling system, which is usually used for the powder compaction process to fabricate the complex multilevel parts, crack formation is crucially detrimental and should be avoided. Among various process factors, tool shape is an important factor to prevent the crack formation during powder compaction process. In this work, the effects of different tool shapes were investigated through the experimental oberservation of pore distribution in real products and the finite element analysis of residual stresses. The results were interpreted based on non-uniform powder density in the compacted parts.

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윤곽밀링시 공구변형에 의한 절삭표면 형상의 예측 (Prediction of the Milled Surface Shapes Considering Tool Deflection Effects in Profile Milling Process)

  • 서태일;조명우
    • 한국정밀공학회지
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    • 제16권7호
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    • pp.203-209
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    • 1999
  • In this paper, we present the methods to predict the milled surface shapes in profile milling process. In the cutting process, tools are deflected due to the cutting forces varying with the imposed depth of cut and feedrate. Thus, the final shapes of the milled surface, generated by the nominal tool trajectory, are different from the required profile. In order to predict the milled surface shapes, we present two methods based on: (1) the deflected tool profile and (2) the trace of contact point between the tool and the workpiece. In the first method, we make an assumption that the milled surface corresponds to the deflected tool profile. In another method, we make we make an assumption that the milled surface is generated by the trace of the contact point between the cutting edge of the tool and workpiece. We present the surface generation process by calculating the trajectory of the contact points on the workpiece. Several simulations and experiments are performed to verify the proposed milled surface prediction methods.

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축대칭 다단 냉간단조 금형설계에 관한 연구 (A Study on the Computer aided Design of Multi-Stage Cold Forging Die for Rotationally Symmetric Parts.)

  • 최재찬;김성원;조해용;김형섭
    • 한국정밀공학회지
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    • 제7권2호
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    • pp.95-104
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    • 1990
  • This paper descirbes some research of Computer-aided Design of multi-stage cold forging die of rotationally symmetric parts produced by the press or former. An approach to the system is based on knowledge based system. Knowledges for tool design are extracted from the plasticity theory, handbooks, relevent references and empirical know-how of experts in cold forging companies. The deveoped system is composed of three main modules such as die design module, punch design module, tool elements design module which are sued independently or in all. Using this system, design parameters (types of dies, geometric shapes and dimensions of dies, types of punches, geometric shapes and dimensions of punches, geometric shapes and dimensions of tool elements) in each operation are determined and the output is generated in graphic form. The develpoed system, aids designer, provides powerful capability for designing dies, punches and tool elements.

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고속카메라를 이용한 절삭공구변형의 보상에 관한 연구 (Compensation for Machining Error included by Tool Deflection Using High-Speed Camera)

  • 배종석;김건희;윤길상;서태일
    • 소성∙가공
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    • 제16권1호
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    • pp.15-19
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    • 2007
  • This paper presents an integrated machining error compensation method based on captured images of tool deflection shapes in flat end-milling processes. This approach allows us to avoid modeling machining characteristics (cutting forces, tool deflections and machining errors etc.) and accumulating calculation errors induced by several simulations. For this, a high-speed camera captured images of real deformed tool shapes which were cutting under given machining conditions. Using image processes and a machining error model, it is possible to estimate tool deflection in cutting conditions modeled and to compensate for machining errors using an iterative algorithm correcting tool paths. This corrected tool path can effectively reduce machining errors in the flat end-milling process. Experiments are carried out to validate the approaches proposed in this paper. The proposed error compensation method can be effectively implemented in a real machining situation, producing much smaller errors.

Zigzag 밀링가공에서 공구경로 최소화를 위한 가공방향 결정방법 (Determination of Cutting Direction for Tool Path Minimization in Zigzag Milling Operation)

  • 김병극;박준영
    • 대한산업공학회지
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    • 제27권1호
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    • pp.69-88
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    • 2001
  • In the zigzag milling operation, an important issue is to design a machining strategy which minimizes the cutting time. An important variable for minimization of cutting time is the tool path length. The tool path is divided into cutting path and non-cutting path. Cutting path can be subdivided into tool path segment and step-over, and non-cutting path can be regarded as the tool retraction. We propose a new method to determine the cutting direction which minimizes the length of tool path in a convex or concave polygonal shape including islands. For the minimization of tool path length, we consider two factors such as step-over and tool retraction. Step-over is defined as the tool path length which is parallel to the boundary edges for machining area and the tool retraction is a non-cutting path for machining any remaining regions. In the determination of cutting direction, we propose a mathematical model and an algorithm which minimizes tool retraction length in complex shapes. With the proposed methods, we can generate a tool path for the minimization of cutting time in a convex or concave polygonal shapes including islands.

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ESC 공정으로 제작된 금형강의 가공특성연구 (Machining Characteristics of Tool Steels Manufactured by Electro Slag Casting Process)

  • 김정운;김봉준;이득우;문영훈
    • 대한기계학회논문집A
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    • 제26권6호
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    • pp.1120-1126
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    • 2002
  • Machining characteristics of tool steels manufactured by electro slag casting process has been investigated in this study. For the estimation of machinability, turning and drilling tests are carried out. The chip shapes at various velocities are investigated for the comparison of turning workabilities of tool steels because the chip shapes reflect characteristics of cutting resistance. In case of drilling test, feed motor currents measured by a hall sensor are used as a measure for the drilling resistance. The machining characteristics of the tool steels are strongly correlated with tensile properties, such as tensile strength, hardness, and ductility. In case of turning workability, it was found to be favoured by the higher tensile strength, while the opposite is true far the drilling workability. The electro-slag casted materials show better turning workability in the viewpoint of chip shapes and, the quenching-tempered electro-slag casted material has relatively better drilling machinability than that of the annealed one.

인볼류우트 커터인선의 초기결손 예측에 관한 연구 (Study on the Analytical Prediction of Premier Chipping in Involute Gear Cutting Process)

  • 김재갑;김정두
    • 대한기계학회논문집
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    • 제16권7호
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    • pp.1266-1277
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    • 1992
  • 본 연구에서는 공구의 형상과 절삭조건에 따른 공구의 결손형태를 예측하기 위하여 현재 가장 널리 쓰이고 있는 인볼류우트커터의 결손형태를 절삭날의 응력분포 값으로 예측하고 실험에 의하여 검증함과 동시에 기어 절삭실험을 통한 공구 결손의 성장거동을 고찰하였으며, 또한 마멸과 결손이 발생함에 따른 절삭력의 변화와 평형을 관찰하여 상호관련성을 비교함으로써 인볼류우트 기어커터의 초기 결손을 해석적으로 예측하였다.

Exploring Low-Cost Grid-based Tactile Instruments for Understanding and Reproducing Shapes for People with Visual Impairments

  • Yeojin Kim;Jiyeon Han;Uran Oh
    • International journal of advanced smart convergence
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    • 제12권3호
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    • pp.127-140
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    • 2023
  • While tools exist for blind people to understand shapes, these are not commercially available nor affordable and often require the assistance of sighted people. Thus, we designed two low-cost grid-based tactile tools using toggle buttons (TogGrid) and cotton balls (CottonGrid). To assess the potential of these as an educational tool, we conducted a user study with 12 people with visual impairments where they were asked to understand and reproduce shapes under different conditions. Although CottonGrid is relatively cheap and easy to make, findings show that TogGrid was perceived to be better in terms of perceived easiness, task completion time, accuracy, and preference in general. Particularly, participants valued TogGrid for enabling them to identify and correct errors. Based on the findings, we provide implications for utilizing toggle buttons for designing educational instruments for learning and expressing shapes for blind people.

민감도법을 이용한 단조 공정에서의 예비성형체 설계

  • 심현보;노현철
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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    • pp.291-296
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    • 2000
  • The sensitivity method has been applied to find perform shape that results in the desired shape after forging. As a basic example, initial shape of specimen for the cylinder shape without barrelling after forging has been found. The method is then applied to various shapes of 3D free forging and initial shapes of the corresponding specimens after forging have been found successfully. The sensitivity method is proven to be an effective and accurate tool for the preform design.

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볼엔드밀 중삭가공시 커습에 의한 절삭특성과 공구마모 (Effect of Cusp on the Cutting Characteristics and Tool Wear of Semi-finishing in Ball End Milling)

  • 조철용;문상돈;류시형
    • 한국공작기계학회논문집
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    • 제15권5호
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    • pp.79-84
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    • 2006
  • In modem manufacturing, many products that have geometrically complicated features, including three-dimensional sculptured surfaces, are designed and produced. In the production of these complex-shaped mechanical components, e.g. automobile dies, molds, and various engineering applications, the ball-end milling process is one of the most widely used NC machining processes that consists of roughing, semi-finishing and finishing. In semi-finishing, cusps remained after roughing according to the used tools that have two patterns of stairs and wave shapes. These cusp shapes have air-cut in cutting and instability caused by high cutting speed that affects the cutting characteristics such as cutting force and tool wear. Cutting characteristics are measured and analyzed through cutting force, FFT analysis of cutting force and tool wear along cutting length according to low tool paths with same metal removal rate. As a results of the experiments, this study suggests the optimal conditions of tool path and cutting direction. This approach for the cutting characteristics of semi-finishing provides a useful aid for the productivity and efficiency improvements of NC machining processes.