• Title/Summary/Keyword: Cutting Direction

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An Algorithm for Reducing the Tool Retraction Length in Zigzag Pocket Machining (Zigzag 포켓가공에서 공구후퇴 길이를 줄이는 알고리듬)

  • Kim, Byoung Keuk;Park, Joon Young
    • Journal of Korean Institute of Industrial Engineers
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    • v.28 no.2
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    • pp.128-138
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    • 2002
  • In this paper, we address how to reduce the length of tool retraction in a zigzag pocket machining. Tool retraction, in a zigzag pocket machining, is a non-cutting operation in which the tool moves to any remaining regions for machining. We developed an algorithm of generating tool retraction length in convex or concave polygonal shapes including islands. In the algorithm, we consider concave areas of cutting direction in the polygonal shape. Considering concave areas of cutting direction, the polygonal shape is decomposed to subregions which do not need any tool retraction. Using the proposed algorithm, we calculated the shortest length of tool retraction in cutting direction. Examples are shown to verify the validity of the algorithm.

A study on the chatter vibration of two degree of freedom systems (2자유도 채터진동의 특성에 관한 연구)

  • Kim, Jeong-Suk;Kang, Myeong-Chang;Kim, Byeong-Ryoung
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.4
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    • pp.216-226
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    • 1993
  • Three dimensional cutting is considered as an equivalent orthogonal cutting through the plane containing both the cutting velocity vector and the chip flow velocity vector in dynamic cutting process. An analytical expression of dynamic cutting force is obtained from the cutting parameters determined by the static cutting. Particular attention is paid to the energy supplied to the vibratory system of cutting tool with two degree of freedom. In this approach, the phase lag of the horizontal vibration of the tool behind the vertical vibration and the direction angle of the fluctuating cutting force is considered in point of stability limits. Chatter vibration can be effectively suppressed by relatively increasing the spring constant and the damping coefficient of the cutting system in the vertical cutting force direction. A good agreement is found between the stability limits predicted by theoretical value and experimental results.

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Kinematical Characteristics of Vibration Assisted Cutting Device Constructed with Parallel Piezoelectric Stacked Actuators (평행한 적층 압전 액추에이터로 구성된 진동절삭기의 기구학적 특성 고찰)

  • Loh, Byoung-Gook;Kim, Gi-Dae
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.12
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    • pp.1185-1191
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    • 2011
  • The kinematic characteristics of cutting device significantly affects cutting performance in 2-dimensional elliptical vibration cutting(EVC) where the cutting tool cuts workpiece, traversing a micro-scale elliptical trajectory in a trochoidal motion. In this study, kinematical characteristics of EVC device constructed with two parallel stacked piezoelectric actuators were analytically modeled and compared with the experimental results. The EVC device was subjected to step and low-frequency(0.1 Hz) sinusoidal inputs to reveal only its kinematical displacement characteristics. Hysteresis in the motion of the device was observed in the thrust direction and distinctive skew of the major axis of the elliptical trajectory of the cutting tool was also noticed. Discrepancy in the voltage-to-displacement characteristics of the piezoelectric actuators was found to largely contribute to the skew of the major axis of the elliptical trajectory of the cutting tool. Analytical kinematical model predicted the cutting direction displacement within 10 % error in magnitude with no phase error, but in estimating the thrust direction displacement, it showed a $27^{\circ}$ of phase-lag compared with the measured displacement with no magnitude error.

Optimal design for face milling cutter by simulation

  • Kim, J.H.;Lee, B.C.;Kim, H.S.
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.2
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    • pp.76-85
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    • 1993
  • Based on the cutting force model, three-dimensional optimal design model was developed and optimal designed tool which is minimized cutting force is developed by computer simulation technique. In this model the objective function which is minimized resultant cutting force was used and the variables are radial rake angle, axial rake angle, lead angle of the tool. The cutting forces using conventional and optimal tools by simulation, are compared and analyzed in time and frequency domains. In time domain the cutting force of optimal tool in feed direction was more reduced and less fluctuated than that of conventional tool. Cutting forces of optimal tool in X-and Z-directions are shown a little increased than those of conventional tool. In frequency domain amplitude of insert frequency components of optimal tool in feed direction was more reduced than that of convent- ional tool. The amplitudes of insert frequency components of optimal tool in X-and Z-direction are a little increased than those of conventional tool. As the reduction of amplitude and fluctuations of the cutting force, Optimal tool is considered that tool life and surface roughness would be improved, and stable cutting would be expected.

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A Study on the Elongation Change of Fabric according to the Cutting Lines (절개선을 활용한 직물의 신장변화에 관한 연구)

  • Lee, Joung-Suk;Sung, Su-Kwang;Lee, In-Ah
    • Fashion & Textile Research Journal
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    • v.4 no.3
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    • pp.261-265
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    • 2002
  • To propose a basic material that can improve the crumples in the knee area and can be applied as an element of garment design, the present study examined the elongation rates of the samples by differentiating the number of cutting lines according to the direction of the fabric, and then determined the puckering phenomenon by judging the conditions of the seams based on the looks of seam lines after bi-axil elongation. After the subjective evaluation on the knee areas of both the standard and modified trousers, the following conclusion was drawn : The elongation rates of the samples are: warp (3.98%)cross-legged (-0.2)>squatting down (-0.4); those in the modified trousers feel more comfortable when sitting on a chair (0.2)>cross-legged (0)>squatting down (-0.6). In the cross-legged posture, the modified trousers (0) has higher scores in the subjective evaluation than the standard ones (-0.2). The evaluation on the looks of needleworks in the samples with cutting lines along the direction of the fabric: weft2 (5.0)

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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On Cutting Characteristics Change of Low Temperature Cooling Tool -Cutting Characteristics of Cage Motor Rotor- (저온냉각공구의 절삭특성 변화 -모타 회전자의절삭특성-)

  • 김순채
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1995.10a
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    • pp.37-43
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    • 1995
  • The cutting process of cage motor rotor require high precision and good roughness, the surface roughness fo cutting face is very important factor with effect on the magnetic flux density of cage motor rotor. The paper describes a cause of decrease in the cutting force and roughness on low temperature cooling tool by means of analysis on the mechanism of force system at cutting condition and experimental findings. The main results as compared with the room temperature cutting are as follow : 1) The cutting resistance decreased due to low temperature cooling tool. 2) The surface roughness decreased due to low temperature cooling tool. 3) The low temperature cooling tool effected machinability of the cutting direction in machined surface. 4) The low temperature cooling decreased burr of corner in feed direction.

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On-line Estimation of Radial Immersion Ratio Using Cutting Force and Instantaneous Cutting Force Ratio in Face Milling (정면밀링 가공 중 절삭력과 순간 절삭력 성분비를 이용한 반경방향 절입비의 실시간 추정)

  • Kim, Myeong-Gon;Gwon, Won-Tae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.8 s.179
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    • pp.2123-2130
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    • 2000
  • Radial immersion ratio is an important factor to determine the threshold in face milling and should be estimated in process for automatic force regulation. In this paper, presented is a method of on-line estimation of the radial immersion ratio using cutting force. When a tooth finishes sweeping, sudden drop of cutting forces occurs. This force drop is equal to the cutting force that acts on a single tooth at the swept angle of cut and can be obtained from cutting force signal in feed and cross-feed direction. 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 force and predetermined ratio, the radial immersion ratio is estimated. Various experiments show that the radial immersion ratio and instantaneous ratio of the radial to tangential direction cutting force can be estimated very well by the proposed method.

An experimental study on the roundness effect for the cutting conditions in a cylinder cutting by end mill (엔드밀에 의한 원통 가공시 절삭조건에 따른 진원도의 실험적 연구)

  • 박희견
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.4
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    • pp.52-60
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    • 1999
  • In this study the effect of roundness error with respect to the cutting conditions using the external cylindrical work piece by end mill cutting in a machining center was studied. the end mill used in this study is HSS coated with Ti-N which is of Ø 12-4 flutes. The material of workpiece is SM20C and cutting oil is used as a cooling flued The cutting experiments were carried out for the several cutting conditions(depth of cut height of end mill feed rate revolution per minute and cutting direction) and their roundness effects were compared using the least squares circle measuring method. The experimental results are summarized as follows : 1) The cutting depth is dominant for the roundness of a cylindrical work piece and the cutting speed must be determined precisely when the cutting depth is large 2) When the cutting direction in circular manufacturing is the same with the spindle rotation i.e up-cutting condition the surface roundness is also improved.

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Underwater Laser Cutting of Thick Stainless Steel in Various Cutting Directions for Application to Nuclear Decommissioning

  • Shin, Jae Sung;Oh, Seong Y.;Park, Seung-Kyu;Kim, Taek-Soo;Park, Hyunmin;Lee, Jonghwan
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.19 no.3
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    • pp.279-287
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    • 2021
  • For application in nuclear decommissioning, underwater laser cutting studies were conducted on thick stainless-steel plates for various cutting directions using a 6 kW fiber laser. For cutting along the horizontal direction with horizontal laser irradiation, the maximum cutting speed was 110 mm·min-1 for a 48 mm thick stainless-steel plate. For cutting along the vertical direction with horizontal laser irradiation, a maximum speed of 120 mm·min-1 was obtained for the same thickness, which confirmed that the cutting performance was similar but slightly better. Moreover, when cutting with vertically downward laser irradiation, the maximum cutting speed was 120 mm·min-1 for a plate of the same thickness. Thus, the cutting performance for vertical irradiation was nearly identical to that for horizontal irradiation. In conclusion, it was possible to cut thick stainless-steel plates regardless of the laser irradiation and cutting directions, although the assist gas rose up due to buoyancy. These observations are expected to benefit laser cutting procedures during the actual dismantling of nuclear facilities.