• Title/Summary/Keyword: End-milling cutter

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Analytical Prediction of Chatter Vibration in Milling Process (밀링 가공 시 채터 진동 예측의 해석적 방법)

  • Jeong, Nak-Shin;Yang, Min-Yang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.3
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    • pp.210-217
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    • 2009
  • This paper presents the analytical prediction of stability lobes in milling. The stability lobes are obtained by measuring the frequency response function (FRF) of a machining center at the cutting point of the end mill cutter, identifying cutting constants, and approximating cutting force coefficients. The stability lobes are experimentally verified through cutting tests.

Ball end milling of sculptured surface models by considering machinability (절삭성을 고려한 자유곡면 모형의 볼 엔드 밀링가공에 관한 연구)

  • 박천경;맹희영
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.6
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    • pp.2048-2061
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    • 1991
  • As compared with other cutting types, the ball end milling process causes a complexity in cutting system and a falling-off of machinability. In order to increase the productivity and efficiency in th NC machining of sculptured surfaces, this study carried out the qualitative linearized evaluation about the ball end milling system and applied their practical expressions to the technological processor at the cutter path planning stage. The evaluated expressions were proved to be adequate for practical use from an accuracy point of view and the estimation models were applied to sculptured surface machining processes for finding variable machining conditions. Consequently, it was recognized that variable machining conditions bring about the dispersion of force system and the reduction of machining time by more than 50%.

Tool Trajectory of Ball-End Mill in Consideration of Deflection when Pencil Cutting (펜슬가공시 공구변형을 고려한 볼엔드밀이 가공 궤적)

  • 윤경석
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1997.10a
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    • pp.88-93
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    • 1997
  • Ball-end milling process is widely used in the die and mold manufacturing because of suitable for the machining of free-form surface. Pencil cutting can eliminate overload in uncut area caused by large diameter of ball-end mill before finish cutting. As the ball-end mill for pencil cutting is long and thin, it is easily deflected by cutting force. The tool deflection when pencil cutting is one of the main reason of the machining errors on a free-from surface. The purpose of the research is to find out the characteristics of deflected cutter trajectory by eddy-current sensor.

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Fracture Detection of Milling Cutter Using Cutting Force and Acoustic Emission Signals (절삭력과 음향방출 신호를 이용한 밀링공구의 파손 검출)

  • Maeng, Min-Jae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.3 no.1
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    • pp.28-37
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    • 2004
  • An on-line monitoring system of endmill failure such as weal, chipping, and fracture is developed using AE, cutting force Characteristic variations of AE and cutting force signals due to endmill failure are identified as follows. When endmill fracture occurs, AE count rate shows a rapid Increase in conjunction with a subsequent decrease while a standard deviation of the principal cutting force Increases significantly. The increase of AE count rate precedes the Increase of standard deviation of principal cutting force. Chipping results in relatively small increase and decrease of AE count rate without any significant variation of the cutting force Gradual increase of AE count rate and mean principal cutting force are Identified to be related with the wear of cutter. A cutter fracture detection algorithm is developed based on the present results. The signals me normalized to enhance the applicability of the algorithm to Wide those of fresh cutters, and qualitative characteristics of AE signals encountered at the moment of fracture are employed. It is demonstrated that the algorithm can detect the cutter fracture successfully.

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Prediction of Mean Cutting Force in Ball-end Milling using 2-map and Cutting Parameter (Z-map과 절삭계수를 이용한 볼엔드밀의 평균절삭력 예측)

  • 황인길;김규만;주종남
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.179-184
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    • 1995
  • A new cutting parameter is defined in the spherical part of ball end-mill cutter. A series of slot cutting experiments were carried out to obtain the cutting parameter. The cutter contact area is expressed as the grid posiotion in the cutting plane using Z map. The cutting forces in each grid are calculated and saved as force map, prior to the average cutting forces calculation. The cutting force, in the arbitrary cutting area, can be easily calculated by summing up the cutting forces of the engaged grid in the force map. This model was verified in the inclined surface cutting by cutting test of a cylindrical part.

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In-Process Cutter Runout Compensation Using Repetitive Learning Control

  • Joon Hwang;Chung, Eui-Sik
    • International Journal of Precision Engineering and Manufacturing
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    • v.4 no.4
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    • pp.13-18
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    • 2003
  • This paper presents the in-process compensation to control cutter ronout and to improve the machined surface quality. Cutter ronout compensation system consists of the micro-positioning servo system with piezoelectric actuator which is embeded in the sliding table to manipulate radial depth of cut in real-time. Cutting force feedback control was proposed in the angle domain based upon repetitive learning control strategy to eliminate chip load variation in end milling process. Micro-positioning control due to adaptive actuation force response improves the machined surface quality by cutter ronout compensation.

Characteristics of Tool Deflection of Ball-end Mill Cutter in Pencil Cutting of the Corner (코너부의 펜슬가공시 볼엔드밀의 공구변형 특성)

  • Wang, Duck-Hyun;Yun, Kyung-Suk
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.2 s.95
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    • pp.123-129
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    • 1999
  • Ball-end milling process is widely used in the die and mold manufacturing because of suitable one for the machining of free-form surface. During the process, the pencil cutting operation can be adopted before finish cut to eliminate overload in uncut area caused by large diameter of ball-end mill. The ball-end mill cutter for the pencil cutting is easily deflected by cutting force due to the long and thin shape, and the tool deflection in pencil cutting is one of the main reason of the machining errors in a free-form surface. The purpose of this study is to find the characteristics of deflected cutter trajectory by constructing measurement system with eddy-current sensor. It was found that the severe reduction of corner radius produced the overcut during the plane cutting. Up cutting method induced the overcut both plane and slope cutting, but down cutting one induced the undercut. From the experiments, down cutting with upward cutting path can generate the small undercut surface.

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Prediction and Measurement of Cutting Force in Side-Milling (사이드 밀링 가공의 절삭력 측정 및 예측)

  • Lee, Chang-Ho;Yang, Min-Yang
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.3
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    • pp.437-446
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    • 2013
  • There have been numerous studies on end milling processes. However, these have been restricted to the application of tools for special cutting purposes. A side milling cutter can handle long, deep, and open slots in a more efficient manner, and it provides the best stability and productivity for this type of milling. In this paper, a method to predict the cutting forces in side milling is described, and simulated cutting forces are compared with those obtained by cutting experiments. In particular, the side milling process easily generates relative motion between the tools and the workpiece because it produces intermittent cutting forces that cause vibrations over a wide frequency range. Therefore, the application of a dynamic cutting model instead of a static cutting model is appropriate to forecast the cutting forces more accurately.

Mean Cutting Force Prediction in Ball-End Milling of Slanted Surface Using Force Map (볼엔드밀 경사면 가공에서 절삭력 맵을 이용한 평균절삭력 예측)

  • 김규만;주종남
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.12
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    • pp.212-219
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    • 1998
  • During machining of dies and molds with sculptured surfaces. the cutter contact area changes continuously and results in cutting force variation. In order to implement cutting force prediction model into a CAM system, an effective and fast method is necessary. In this paper. a new method is proposed to predict mean cutting force. The cutter contact area in the spherical part of the cutter is obtained using Z-map, and expressed by the grids on the cutter plane orthogonal to the cutter axis. New empirical cutting parameters were defined to describe the cutting force in the spherical part of cutter. Before the mean cutting force calculation, the cutting force density in each grid is calculated and saved to force map on the cutter plane. The mean cutting force in an arbitrary cutter contact area can be easily calculated by summing up the cutting force density of the engaged grid of the force map. The proposed method was verifed through the slotting and slanted surface machining with various inclination angles. It was shown that the mean force can be calculated fast and effectively through the proposed method for any geometry including sculptured surfaces with cusp marks and holes.

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A Study on the Cutter Runout In-Process Compensation Using Repetitive Loaming Control (반복학습제어를 이용한 커터 런아웃 보상에 관한 연구)

  • Hwang, Joon;Chung, Eui-Sik;Hwang, Duk-Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.3
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    • pp.137-143
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    • 2002
  • This paper presents the In-process compensation to control cutter runout and improve the machined surface quality. Cutter runout compensation system consists of the micro-positioning servo system with piezoelectric actuator which is embeded in the sliding table to manipulate radial depth of cut in real-time. Cutting force feedback control was proposed in the angle domain based upon repetitive learning control strategy to eliminate chip load variation in end milling process. Micro-positioning control due to adaptive actuation force response improves the machined surface quality by compensation runout effect induced cutting force variation. This result will provide lots of information to build-up the preciswion machining technology.