• Title/Summary/Keyword: tool deflection

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Machined Profile Characteristics for Feedrate Change in Ball End Mill Cutting (볼엔드밀 가공시 이송변화에 따른 가공형상 특성)

  • 왕덕현;김원일;이윤경;임채열;우정윤;박창수
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.2
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    • pp.95-102
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    • 2002
  • Due to the development of the CNC machine tool and CAM software, sculptured surface machining can be broadly used in die and mold industries and ball end milling process is often used for the sculptured surface machining. It is found out how feedrate affects the precision of the machining and also tried to study the most suitable feedrate in specific cutting condition. Two eddy current sensors were used far measuring tool deflections of X, Y axis, dynamometer for cutting force and roundness tester for roundness. It was found that the tool deflection is getting better as tool path is going to further from the center of convex surface. The reason is that the cutting force is increased as the tool approaches to the center. Examining the roundness, cutting force and tool deflection characteristics, it was found that the most suitable feedrate is 90mm/min in convex surface and 120mm/min in concave surface.

Simulation Tool of Rectangular Deflection Yoke for CRT

  • Woo, Duck-Kee;Park, Jong-Jin;Cheun, Jong-Mok;Park, Moo-Yong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.1141-1146
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    • 2003
  • We have developed the three-dimensional simulation tool for the design of deflection yoke. This tool consists of a modeler, a solver and a post-processor. The modeler easily makes models of Deflection Yoke (DY) and ferrite core (Circle, RAC and RTC) by the parameters and supports several element types (line, surface and quadrilateral). The solver calculates charge density and magnetic field of DY by boundary element method (BEM). We can simply evaluate misconvergence, distortion and inductance of DY in the post-processor, so we apply this simulation tool to 32" rectangular deflection yoke. We can conveniently implement the efficient development of DY in the future.

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Prediction of Cutting Force in Ball-end mill Cutting using the Commercial Solid Modeler (상용 Solid Modeler를 이용한 볼 엔드밀 가공의 절삭력 예측)

  • 이재종;박찬훈;최종근;박홍석
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.197-200
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    • 1997
  • In the metal cutting, machining accuracies had affected by tool deflection that had been generated by acting cutting force on the cutting edges. Generally, the CAD/CAM and a solid modeler had used for the simulation of cutting process only. Some NC codes for metal cutting have been generated by these simulation results. But, machining errors that had generated by the tool deflection has not solved using these system. In this study, determination algorithm for integration zone has been studied using the commercial solid modeler. The tool deflection error has calculated by the integration zone between the small chip and the cutting edges.

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The Study on Table Deflection by Stationary State and Feedrate at Loaded (하중 적재시 정지상태 및 이송시 하중에 따른 테이블 처짐에 관한 연구)

  • Lee Seung Soo;Kim Min Ju;Kim Soon Kyung;Seo Sang Ha;Jeon Eon Chan
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.6
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    • pp.41-47
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    • 2004
  • This study is aimed to measure the deflection of loaded table on machine tool. The deflection rate is measured then the table is in a stationary state and is moved. In conclusion we have found that the more load increases, the more the table deflections. Also, we have found that the deflection rate increases in accordance with the speed of movement. Therefore, we have concluded that inspection of machine tool should be done considering the weight of load and the speed of movement. However, since the condition of accuracy test for domestic brand of machine tool is defined as unloaded case, measures should be explored only for loaded case.

Surface Precision due to Change of Cutting Depth and Cutting Location when Ball End Milling (볼엔드밀 가공시 절삭깊이와 가공위치의 변화에 따른 표면정밀도)

  • 박성은;왕덕현;김원일;이윤경
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.274-278
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    • 2000
  • Ball end milling process is widely used in the die and mould manufacturing because of suitableness for the machining of free form surface. But, as ball end mill is long and thin, it is easily deflected by cutting force. In this study, Cutting force, tool deflection and surface precision was measured according to the change of depth and cutting location. Cutting force was acquired with tool dynamometer and a couple of eddy-current sensor measured tool deflection in x-y direction each. After machining, surface precision was measured with roundness tester and coordination measuring machine for sculptured surface angle change and cutting depth.

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Surface Generation in End Milling considering Tool Deflection (엔드밀 가공시 공구변형을 고려한 표면형성 해석)

  • 이상규
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.119-124
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    • 1996
  • End milling operation is very important in machining precision components. Deterioration of surface roughness and surface geometry will cause more process for surface finishing. According to the feed rate and the cutting edge geometry, the cusp which is geometrically uncut surface is determined. To reduce the cost for dinishing operation after end milling, the cusp must be remaianed in small size as possible. Due to the cylindrical type of the end mill, tool deflection is one of the main problems in surface generation. The cutting resistance and the rigidity of the end mill will determine the size of tool deflection. One more important factor which deteriorate surface quality comes from the error in manufacturing end mills. Run-out of end mill which is the difference of the radius of each cutting edges will produce the difference of the cusp size in every rotation of end mill. These three major factors to the surface quality will be analized and the result will be compared with experimental ressult.

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Optimal Cutting Condition in Side Wall Milling Considering Form Accuracy (측벽 엔드밀 가공에서 형상 정밀도를 고려한 최적 절삭 조건)

  • 류시형;최덕기;주종남
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.10
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    • pp.31-40
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    • 2003
  • In this paper, optimal cutting condition to minimize the form error in side wall machining with a flat end mill is studied. Cutting forces and tool deflection are calculated considering surface shape generated by the previous cutting such as roughing. Using the form error prediction method from tool deflection, optimal cutting condition considering form accuracy is investigated. Also, the effects of tool teeth number, tool geometry and cutting conditions on form error are analyzed. The characteristics and the difference of generated surface shape in up and down milling are discussed and over-cut free condition in up milling is presented. Form error reduction method through successive up and down milling is also suggested. The effectiveness and usefulness of the presented method are verified from a series of cutting experiments under various cutting conditions. It is confirmed that form error prediction from tool deflection in side wall machining can be used in optimal cutting condition selection and real time surface error simulation for CAD/CAM systems. This study also contributes to cutting process optimization for the improvement of form accuracy especially in precision die and mold manufacturing.

An Experimental Study on the Dimensional Error in Ball End Milling (볼 엔드밀 가공에서 치수오차에 관한 실험적 연구)

  • 심기중;유종선;정진용;서남섭
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.7
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    • pp.62-69
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    • 2004
  • This paper presents an experimental study on the dimensional error in ball-end milling. In the 3D free-formed surface machining using ball-end milling, while machining conditions are varied due to the Z component of the feed and existing hemisphere part of the ball-end mill, the mechanics of ball-end milling are complicated. In the finishing, most of cutting is performed the ball part of the cutter and the machined surface are required the high quality. But the dimensional errors in the ball-end milling are inevitably caused by tool deflection, tool wear, thermal effect and machine tool errors and so on. Among these factors, the most significant one of dimensional error is usually known as tool deflection. Tool deflection is related to the instantaneous horizontal cutting force and varied the finishing cutting path. It lead to decrease cutting area, thus resulting cutting forces but the dimensional precision surface could not be obtained. So the machining experiments are conducted fur dimensional error investigation and these results may be used for decrease dimensional errors in practice.

Cutting Condition Selection for Geometrical Accuracy Improvement in End Milling (엔드밀 가공에서 형상 정밀도 향상을 위한 절삭 조건 선정)

  • 류시형;최덕기;주종남
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1784-1788
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    • 2003
  • For the improvement of geometrical accuracy in end milling, cutting method and cutting condition selection are investigated in this paper. As machining processes are composed of several steps such as roughing, semi-finishing. and finishing, cutting forces and tool deflection are calculated considering surface shape generated by the previous cutting. The effects of tool teeth numbers, tool geometry, and cutting conditions on the form error are analyzed. Using the from error prediction method from tool deflection, cutting condition for geometrical accuracy improvement is discussed. The characteristics and the difference of generated surface shape in up and down milling are dealt with and over-cut free condition in up milling is presented. The form error reduction method by alternating up and down milling is also suggested. The effectiveness of the presented method is examined from a set of cutting tests under various cutting conditions. This research contributes to cutting process optimization for the geometrical accuracy improvement in die and mold manufacture.

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정형가곡을 위한 공구경로 보상 : 윤곽가공을 중심으로

  • 서석환;조정훈
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1992.10a
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    • pp.34-38
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    • 1992
  • Geometry based CAD/CAM system is hard to achieve "net shape machining" For a net shape machining, the machining errors should be compensated by off-line CAD/CAM system followed by on-line control system. In this paper, we investigate an off-line compensation scheme for the machining errors due to tool deflection in contouring operation. The significance of the deflection errors is first shown, and a compensation is sought via modifying the nominal tool path. In modification, tool deflection amount is iteratively compensated until the deflection amount is iteratively compensated until the deflected path results in the desired contour within a tolerance. The path modification algorithm has been tested via computer simulation. The developed algorithm can be used as a postprocessor for the current CAD/CAM system based on geometric modeling as a means for enhancing the machining accuracy.