• Title/Summary/Keyword: Cutting Force

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Generalized Method for Constructing Cutting Force Coefficients Database in End-milling (엔드밀링 가공에서 절삭력 계수 데이터베이스 구현을 위한 일반화된 방법론)

  • 안성호;고정훈;조동우
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.8
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    • pp.39-46
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    • 2003
  • Productivity and machining performance can be improved by cutting analysis including cutting force prediction, surface error prediction and machining stability evaluation. In order to perform cutting analysis, cutting force coefficients database have to be constructed. Since cutting force coefficients are dependent on cutting condition in the existing research, a large number of calibration tests are needed to obtain cutting force coefficients, which makes it difficult to build the cutting force coefficients database. This paper proposes a generalized method for constructing the cutting force coefficients database us ins cutting-condition-independent coefficients. The tool geometry and workpiece material were considered as important components for database construction. Cutting force coefficients were calculated and analyzed for various helix and rake angles as well as for several workpiece. Furthermore, the variation of cutting force coefficients according to tool wear was analyzed. Tool wear was found to affect tool geometry, which results in the change of cutting force coefficients.

A Mechanistic Model for 3 Dimensional Cutting Force Prediction Considering Ploughing Force in Face Milling (정면밀링가공에서 쟁기력을 고려한 3차원 절삭력 모델링)

  • 권원태;김기대
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.2
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    • pp.1-8
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    • 2002
  • Cutting force is obtained as a sum of chip removing force and ploughing force. Chip removing force is estimated by multiplying specific cutting pressure by cutting area. Since ploughing force is caused from dullness of a tool, its magnitude is constant if depth of cut is bigger than a certain value. Using the linearity of chip removing force to cutting area and the constancy of ploughing force regardless of depth of cut which is over a certain limit each force is separated from measured cutting force and used to establish cutting force model. New rotation matrix to convert the measured cutting force in reference axes into the forces in cutter axes is obtained by considering that tool angles are projected angles from cutter axes to reference axes.. Spindle tilt is also considered far the model. The predicted cutting force estimated from the model is in good agreement with the measured force.

Cutting Force Estimation Considering the Specific Cutting Force Constant (비절삭 저항상수에 따른 절삭력 예측)

  • Kim, Jong-Do;Yoon, Moon-Chul
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.10
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    • pp.75-82
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    • 2019
  • Few studies have been conducted regarding theoretical turning force modelling while considering cutting constant. In this paper, a new cutting force modelling technique was suggested which considers the specific cutting force coefficients for turning. The specific cutting force is the multiplication of the cutting force coefficient and uncut chip thickness. This parameter was used for experimental modelling and prediction of theoretical cutting force. These coefficients, which can be obtained by fitting measured average forces in several conditions, were used for the formulation of three theoretical cutting forces for turning. The cutting force mechanism was verified in this research and its results were compared with each of the experimental and theoretical forces. The deviation of force was incurred by a small amount in this model and the predicted force considering feed rate, nose radius, and radial depth shows a physical behavior in main force, normal force, and feeding force, respectively. Therefore, this modelling technique can be used to effectively predict three turning forces with different tool geometries considering cutting force coefficients.

Control of a CNC Machining Center Using the Indirect Measurement of the Cutting Force (절삭력 간접 측정을 이용한 CNC공작기계 제어)

  • 송진일;손주형;권동수;김성권
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.11
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    • pp.9-20
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    • 1998
  • In recent manufacturing process, the increase of productivity has been attempted by reducing machining time with the increase of cutting force. However, the excessive increase of cutting force can cause tool breakage and have a bad effect on both manufacturing machine and workpiece. Thus, it is necessary to estimate and control the cutting force in real time during the process. In this study, use of disturbance observer is proposed for the indirect cutting force estimation. The estimated cutting force is used for the real-time control of feedrate, making the actual cutting force follow the reference force command. Since the suggested method does not need an expensive sensor like a dynamometer, the method is expected to be used practically. Since the actual cutting force follow the reference force, resulting the reducing of the machining time the increase of productivity are also expected, and the quality of cutting surface has been improved due to the adjusted feedrate. Besides, an actual constant cutting force guarantees the prevention of tool breakage. To show the effectiveness of the suggested cutting force control method, an experimental setup has been made without sensor and applied to several workpieces. Experiments show that the suggested method is effective to cutting force control of a CNC machining center.

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Fast Force Algorithm of End Milling Processes and Its Application to the NC Verification System (엔드밀링의 효과적인 절삭력 모델과 NC 검증시스템으로의 응용)

  • 김찬봉;양민양
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.7
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    • pp.1555-1562
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    • 1995
  • This study represents the non-dimensional cutting force model. With the non-dimensional cutting force model it is possible to estimate efficiently the maximum cutting force during one revolution of cutter. Using the non-dimensional cutting force model, the feed rate and spindle speed are adjusted so as to satisfy the maximum cutting force and maximum machining error. To verify the accuracy and efficiency of the non-dimensional cutting force model, a series of experiments were conducted, and experimental results proved and verified the non-dimensional cutting force model. The NC toolpath verification system developed in this paper uses the non-dimensional cutting force model, so that it is effective for calculating the cutting force and adjusting the cutting conditions.

On-line Simulaneous Identification of Immersion Ratio and Cutting Force Ratio using Cutting Forces in Face Milling (정면밀링에서 절삭력을 이용한 절입비와 절산력비의 실시간 추정)

  • 김명곤
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.4
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    • pp.91-98
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    • 2000
  • In this paper , presented is a method of on-line estimation of the radial immersion ratio and cutting force ratio using cutting force. When a tooth finishes sweeping, sudden drop of cutting forces occurs. These force drops are equal to the cutting forces that act on a single tooth at the swept angle of cut and can be obtained from cutting force signals in feed and crossfeed directions. The ratio of cutting forces in feed and cross-feed directions acting on the single tooth at the swept angle of cut is a function of the swept angle of cut and the ratio of radial to tangential cutting force. In the research, it is found that the ratio of radial to tangential cutting force is not affected by cutting conditions and axial rake angle. Therefore, the ratio of radial to tangential cutting force determined by just one preliminary experiment can be used regardless of the cutting conditions. Using the measured cutting forces, the radial immersion ratio is estimated along with the cutting force ratio at that immersion angle. Various experiments show that the radial immersion ratio and instantaneous ratio of the radial to tangential direction cutting force can be estimated by the proposed method very well.

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Automatic Feedrate Adjustment for 2D Profile Milling (2차원 윤곽가공에서 이송률 자동 조정)

  • 고기훈;서정철;최병규
    • Korean Journal of Computational Design and Engineering
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    • v.5 no.2
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    • pp.175-183
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    • 2000
  • Proposed in this paper is a model-bated AFA (automatic feedrate-adjustment) method for maintaining smooth cutting-loads (i.e., cutting-force) during 2D-profile milling. Before the cutting-force model was established, some assumptions were verified through a series of preliminary cutting experiments (The results found that the curving-force was independent of the cutting speed and the cutting action at the cutter bosom). From the data obtained during the main cutting experiments, a “chip-load/cutting-force model”representing the cutting-force as a function of the chip-load (i.e., effective cutting-depth) and a feedrate is proposed. Based on the model. an AFA scheme for maintaining smooth cutting-force by adjusting the feedrate (i.e., F-code) according to the changes in chip-load was proposed. To check the validity of the proposed AFA scheme. another set of cutting experiments was conducted by using feedrate-adjusted NC-data while monitoring the actual machining processes using an accelerometer. The experimental results showed that the proposed AFA-scheme was quite effective.

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Development of Cutting Simulation System for Prediction and Regulation of Cutting Force in CNC Machining (CNC 가공에서 절삭력 예측과 조절을 위한 절삭 시뮬레이션 시스템 개발)

  • 고정훈;이한울;조동우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.3-6
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    • 2002
  • This paper presents the cutting simulation system for prediction and regulation of cutting force in CNC machining. The cutting simulation system includes geometric model, cutting force model, and off-line fred rate scheduling model. ME Z-map(Moving Edge node Z-map) is constructed for cutting configuration calculation. The cutting force models using cutting-condition-independent coefficients are developed for flat-end milling and ball-end milling. The off-line feed rate scheduling model is derived from the developed cutting force model. The scheduled feed rates are automatically added to a given set of NC code, which regulates the maximum resultant cutting force to the reference force preset by an operator. The cutting simulation system can be used as an effective tool for improvement of productivity in CNC machining.

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Development of mean specific cutting pressure model for cutting force analysis in the face milling process (정면 밀링의 절삭력 해석을 위한 평균 비절삭저항 모델의 개발)

  • Lee, B.C.;Hwang, J.C.;Kim, H.S.
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.4
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    • pp.13-25
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    • 1994
  • In order to design and improve a new machine tool, there is a need for a better understanding of the cutting force. In this paper, the computer programs were developed to predict not only the mean specific cutting pressure but also the cutting force. The simulated cutting forces in X, Y, Z directions resulted form the developed cutting force model were compared with the measured cutting forces in the time and frequency domains. The simulated cutting forces resulted from the new cutting force model have a good agreement with the measured force in comparison with these resulted from the existing cutting force model.

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Prediction of Cutting Forces and Estimation of Size Effects in End Milling Operations by Determining Instantaneous Cutting Force Constants (엔드 밀링 공정에서 순간 절삭력 계수 결정을 통한 절삭력 예측 및 크기효과 평가)

  • Kim, Hong Seok
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.6
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    • pp.1003-1009
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    • 2013
  • This paper presents a simple procedure to obtain the instantaneous cutting force constants needed to predict milling forces. Cutting force data measured in a series of slot milling tests were used to determine the cutting force constants at different feed rates. The values of the cutting force constants were determined directly at the tool rotation angle that maximized the uncut chip thickness. Then, the instantaneous cutting force constant was obtained as a function of the instantaneous uncut chip thickness. This approach can greatly enhance the accuracy of the mechanistic cutting force model for end milling. In addition, the influences of several cutting parameters on the cutting forces, such as the tool helix angle and axial depth of cut, were discussed.