• Title/Summary/Keyword: Corner Cutting

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A study on the optimal conditions for machining accuracy when endmill fillet cutting at the corner (코너부 모깍기 엔드밀가공시 가공정밀도의 최적조건에 관한 연구)

  • Choi, Sung-Yun;Kwon, Dae-Gyu;Park, In-Su;Wang, Duck-Hyun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.15 no.4
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    • pp.101-108
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    • 2016
  • Endmill fillet cutting at the corner was conducted with the online measurement of cutting forces and tool deflection by a tool dynamometer and an eddy current sensor system. The profile of the machined surface was also compared with the CAD profile with a Coordinate Measuring Machine (CMM) and CALYPSO software. It was found that the end mill cutter with four blades has a better surface profile than that with two blades, and the cutting forces and tool deformation were increased as the cutting speed was increased. When the tool located at the degree $45^{\circ}$ corner was found to conduct the maximum cutting force than started to the point of the workpiece. As it was compared with the CMM and ANOVA analysis result in the case that the cutting force and tool deformation was the maximum, it was found that the result was affected by the spindle speed and the number of blades.

A Study on the Laser Cutting Characteristics of Magnesium alloys (마그네슘합금의 레이저 절단가공 특성에 관한 연구)

  • Jung, Han-Byul;Kim, Hyung-Sun
    • Journal of Advanced Engineering and Technology
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    • v.11 no.4
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    • pp.227-235
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    • 2018
  • Studies on the laser cutting processing characteristics of magnesium alloys can be divided into three parts, comparing the cutting faces of magnesium alloy and aluminum alloy, observing the shape of the corner where straight lines meet, and observing the straight lines and arcs. First, there were no laser cutting conditions for magnesium alloys, so it was observed to cut magnesium alloy and aluminum alloy under the same processing conditions as aluminum alloy to shape and surface of the cut surface. Next, to observe the characteristics of the corner, we observed the shape of the corner according to the angle change of the part where the two lines meet, and finally we observed various angles to observe the characteristics of the part where the arc meets the line. Finally, laser cutting processing characteristics of magnesium alloys and aluminum alloys obtained based on the above study contents were summarized.

Effects of corner cuts and angles of attack on the Strouhal number of rectangular cylinders

  • Choi, Chang-Koon;Kwon, Dae-Kun
    • Wind and Structures
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    • v.6 no.2
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    • pp.127-140
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    • 2003
  • An investigation into the effect of corner cuts on the Strouhal number of rectangular cylinders with various dimensional ratios and various angles of attack is described. The Strouhal number given as a function of corner cut size is obtained directly from the aerodynamic behavior of the body in a uniform flow through a series of wind-induced vibration tests. For a quick verification of the validity of the Strouhal numbers obtained in this way, they are compared with the approximated the Strouhal numbers based on Shiraishi's early research. The test results show that the Strouhal number of the model with various corner cuts has a fluctuating trend as the angle of attack changes. For each cutting ratio as the angle of attack increases at each cutting ratio above $15^{\circ}$, the Strouhal number decreases gradually, and these trends are more evident for larger corner cut sizes. However, a certain corner cut size which is effective in reducing the wind-induced vibration can be identified by larger Strouhal numbers than those of other corner cut sizes. Three distinct characteristics of Strouhal number variation can be identified in three regions which are termed as Region I, II, and III based on the general trend of the test results. It is also found that the corner cut is effective in one region (Region-II) and less effective in another one (Region-III) when only the vortex-induced vibration occurs.

Evaluating Stability of a Transient Cut during Endmilling using the Dynamic Cutting Force Model

  • Seokjae Kang;Cho, Dong-Woo;Chong K. Chun
    • International Journal of Precision Engineering and Manufacturing
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    • v.1 no.2
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    • pp.67-75
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    • 2000
  • virtual computer numerical control(VCNC) arises from the concept that one can experience pseudo-real machining with a computer-numerically-controlled(CNC) machine before actually cutting an object. To achieve accurate VCNC, it is important to determine abnormal behavior, such as chatter, before cutting. Detecting chatter requires an understanding of the dynamic cutting force model. In general, the cutting process is a closed loop system the consists of structural and cutting dynamic. Machining instability, namely chatter, results from the interaction between these two dynamics. Several previous reports have predicted stability for a single path, using a simple cutting force model without run out and penetration effects. This study considers both tool run out and penetration effects, using experimental modal analysis, to obtain predictions that are more accurate. The machining stability during a corner cut, which is a typical transient cut, was assessed from an evaluation of the cutting configurations at the corner.

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Stability Analysis in Transient Cut during Endmilling (엔드밀링가공시 과도 영역에서의 안정성 평가)

  • Kang, Seok-Jae;Cho, Dong-Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.3
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    • pp.195-204
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    • 2001
  • Virtual computer numerical control(VCNC) arises from the concept that one can experience pseudo-real machining with a computer-numerically-controlled(CNC) machine before actually cutting an object. To achieve accurate VCNC, it is important to determine abnormal behavior, such as chatter, before cutting. Detecting chatter requires an understanding of the dynamic cutting force model. In general, the cutting process is a closed loop system that consists of structural and cutting dynamics. Machining instability, namely chatter, results from the interaction between these two dynamics. Several previous reports have predicted stability for a single path, using a simple cutting force model without tool runout and penetration effects. This study considers both tool runout and penetration effects, using experimental modal analysis, to obtain more accurate predictions. The machining stability in the corner cut, which is a typical transient cut, was assessed from an evaluation of the cutting configurations at the corner.

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Spur gear forging tool manufacturing method considering elastic deformation due to shrink-fitting (열박음에 의한 탄성변형을 고려한 평기어금형 제작 방법에 관한 연구)

  • Kang, J.H.;Ko, B.H.;Jae, J.S.;Kang, S.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.381-385
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    • 2006
  • This research introduces easy tool manufacturing method regarding tool manufacturing procedure. In the conventional method, wire cutting machining and lapping operation of corner and render region were performed after shrink-fitting to ensure the accuracy of gear profile. But lapping operation is very difficult due to corner and render is located deep inside of die. In this research, wire cutting operation was performed after $1^{st}$ ring was shrink-fitted to ease lapping operation and increase the accuracy of corner radius. Before $2^{nd}$ ring fitting, lapping was completed. Elastic deformation amount due to $2^{nd}$ ring fitting and cold forging was calculated through finite element analysis and wire cutting specification was offset in that amount. Comparison of gear dimension between analysis and forged part ensures the validity of new manufacturing methods.

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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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Design of Linear, Exponential and Bell Type Discrete Filters for Acceleration and Deceleration of Servo Motors (서보모터의 가감속을 위한 직선형,지수형 및 벨형 이산필터 설계)

  • Shin, Dong-Soo;Chung, Sung-Chong
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.9
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    • pp.52-60
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    • 1997
  • This paper proposes the effective method of the software based motion control by using lenear, exponential and bell type discrete filters for acceleration and deceleration of servo motors. Recursive filters are designed in discrete time domain which can reduce computation time and vibration of motors due to load disturbance. Also it deals with the method which decides the time constants of filters when a machine tool is driven at rapid, cutting and jog feedrate. Validity of the proposed method is verified by corner cutting experiments.

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A Study on the Cutting Forces and Tool Deformation when Flat-ended Pocket Machining (평엔드밀 포켓가공시 절삭력과 공구변형에 관한 연구)

  • Choi, Sung-Yun;Kwon, Dae-Gyu;Park, In-Su;Wang, Duck-Hyun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.2
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    • pp.28-33
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    • 2017
  • Recently, the operation of precision pocket machining has been studied for the high speed and accuracy in industry to increase production and quality. Moreover, the demand for products with complex 3D free-curved surface shapes has increasing rapidly in the development of computer systems, CNC machining, and CAM software in various manufacturing fields, especially in automotive engineering. The type of aluminum (Al6061) that is widely used in aerospace fields was used in this study, and end-mill down cutting was conducted in fillet cutting at a corner with end-mill tools for various process conditions. The experimental results may demonstrate that the end mill cutter with four blades is more advantageous than that of the two blades on shape forming in the same condition precise machining conditions. It was also found that cutting forces and tool deformation increased as the cutting speed increased. When the tool was located at $45^{\circ}$ (four locations), the corner was found to conduct the maximum cutting force rather than the start point of the workpiece. The experimental research is expected to increase efficiency when the economical precision machining methods are required for various cutting conditions in industry.

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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