• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.1
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• pp.95-103
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• 2015

This paper presents the effects of the tool shape on the geometrical characteristics of flat end-milled side walls. A tool shape is characterized by such parameters as helix angle, number of cutting edges, and diameter. The geometrical characteristics of the side walls are represented by the surface profiles in the feed and axial directions, which are orthogonal to each other. The geometrical defects in each direction are estimated based on the instantaneous apparent cutting areas, which are represented by the interference area between the tool and workpiece and that between the cutting edge and workpiece. It is confirmed that a geometrical defect in the feed direction is formed when the tool leaves the workpiece and the curvature of the tool path changes. Defects in the axial direction are also found in the side walls, except for the defect zone in the feed direction. An up-cut using an end-mill with a steeper helix angle, a greater number of cutting edges, and a smaller diameter are thus found to improve the geometrical accuracy of end-milled side walls.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.324-328
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• 2002

Recently, in machining industry much progress has been made by taking advantage of high speed machining. On the other hand as disadvantage high speed machining involves shortening the life of cutting tool. In this research we want to evaluate the performance of appropriate endmill for high speed machining in accordance with surface roughness of land width and clearance angle of flat-endmill

• IE interfaces
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• v.8 no.3
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• pp.155-169
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• 1995

일반적인 CAD/CAM 시스템을 이용해서 생성한 NC-code는 오류의 가능성의 항시 내포되어 있으므로, 실 가공하기 전에 NC-code의 불량 여부를 검사할 필요가 있다. 본 논문에서는 Z-map 형태의 계산모형을 이용한 모의가공의 계산방법을 볼엔드밀, 평엔드밀, 라운드엔드밀에 대해서 도식적으로 설명하였다. 또, 모의가공 된 형상만으로 NC-code의 불량 여부를 검사하는 자체적인 검사방법과 모의가공 된 형상과 설계형상을 비교해서 불량여부를 판별하는 비교 검사방법을 제시하였다. Z-am 모델을 모의가공과 가공형상의 검증에 사용하면, 빠른 속도로 실제가공 상황을 재현 할 수 있고 육안 검증을 포함한 다양한 수치적 검증이 가능하다. 또, 간단한 데이터 구조이므로 필요한 앨고리즘을 효율적이고, 로버스트하게 구현할 수 있다.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.53-59
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• 2011

End milling is available for machining the various shape of products and has been widely applied in many manufacturing industries. The quality of products depends on a machine tool performance and machining conditions. Recognition characteristics of the cutting condition is becoming a critical requirement for improving the utilization and flexibility of present-day CNC machine tools. The measurement of tool wear would be performed by coordinate-measuring machine(CMM). However, the usage of CMM requires much time and cost. In order to overcome the difficulties, on-line measurement(OLM) system was applied for a tool wear measurement. This study shows a reliable technique for the reduction of machining error components by developing a system using a CCD camera and machine vision to be able to precisely measure the size of tool wear in flat end milling for CNC machining. The CCD camera and machine vision attached to a CNC machine can determine tool wear quickly and easily.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.5
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• pp.130-136
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• 2001

The purpose of this study is an evaluation of flat end mills to develop appropriate tools for the high speed machining. First of all, several flat end mills which are produced by different makers are selected to analyze the performances of the tools. Experimental works are also executed to measure cutting farce, tool wear and surface roughness for different cutting conditions. And then the results are compared and analyzed for developing optimal cutting tool in the high speed condition.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.6
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• pp.43-51
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• 2004

A method for form error prediction in side wall machining with a flat end mill is suggested. Form error is predicted directly from the tool deflection without surface generation by cutting edge locus with time simulation. Developed model can predict the surface form error about three hundred times faster than the previous method. Cutting forces and tool deflection are calculated considering tool geometry, tool setting error and machine tool stiffness. The characteristics and the difference of generated surface shape in up milling and down milling are discussed. The usefulness of the presented method is verified from a set of experiments under various cutting conditions generally used in die and mold manufacturing. This study contributes to real time surface shape estimation and cutting process planning for the improvement of form accuracy.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.234-243
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• 1999

Using the geometric and the vector methods, three dimensional surface texture and roughness models in flat end milling are developed. In these models, rear cutting effect on surface generation is considered along with tool run-out and tool setting error including tool tilting and eccentricity between tool center and spindle rotational center. Rear cutting is the secondary cutting of the already machined surface by the trailing cutting edge. The effects of tool geometry and tool deflection on surface roughness are also considered. For representing the surface texture more practically, three dimentional surface topography parameters such as RMS deviaiton, skewness and kurtosis are introduced and used in expressing the surface texture characteristics. Under various cutting conditions, it is confirmed that the developed models predict the real surface profile precisely. These models could contribute to the cutter design and cutting condition selection for the reduction of machining and manual finishing time.

• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.822-826
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• 1997

근래에 들어, 금형생산 시간의 단축과 고정밀도의 제품을 생산하기 위해 실가공전의 설계단계에서 금형 데이터를 수치적으로 검증할 필요가 높아지고 있다. 기존의 저가형 CAM시스템에서 사용된 경로표시법으 로는 이러한 검증이 불가능하기 때문에 새로운 방법의 도입이 필요하며 모의가공 형상의 표현에서도 비매 개변수형 곡면을 이영하는 방법이 널리 사용되고 있다. 본 연구는 3축 금형가곡에 사용되는 볼앤드밀, 평 엔드밀 공구에 대해 Z-map을 기반으로 절삭부위를 비매개변수형 곡면으로 모델링하여 모의가공을 수행하 고자 한다. 또한, 새로운 backeting영역지정 방법을 사용하여 모의가공의 효율을 높였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.7
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• pp.1095-1102
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• 2003

The most important thing in measuring the tool wear is to set up the measurement base. The end mill that is being used for machining of die is difficult to set up the base and to measure the tool wear because of geometric properties of that such as a helix and relief angle. In this study, a new instrument using spindle orientation function in end milling is developed to measure the tool wear and evaluated by the measuring system on the machine. Finally, this new method makes possible the wear measurement of same position and reduces the measuring time compared with the measuring methods such as the microscope and CCD.