• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.471-474
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• 2004

In this paper, a NURBS surface interpolator is proposed which can deal with shapes defined from CAD/CAM programs on a surface basis and can improve contour accuracy. The proposed interpolator is based on newly defined G-codes and includes online tool-path planning suitable for NURBS surface machining. The real-time interpolation algorithm, considering an effective machining method for each machining process and minimum machining time, is executed in an online manner. The proposed interpolator is implemented on a PC-based 3-axis CNC milling system and evaluated through actual machining in terms of machining time and regulation of feedrate and cutting force in comparison with the existing method.

• 한국기계가공학회지
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• 제10권5호
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• pp.13-19
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• 2011

In this paper, the active monitoring and control system is developed. This system can monitor the status of high the speed spindle in real time during its processing, and can analyze its influence of dimensional accuracy and processing if any, and can control the machining condition to realize the machining system equipped with active monitoring and self-diagnostic features. Machining experiment was performed on 3 materials Al, Brass and S45C in order to derive the relation between active monitoring and control algorithm by the machining load. In addition, we measured surface roughness of processing specimen along with the data change of spindle rotating speed and conveying speed according to variation of machining load. Based on these experiments, we derived relations for each material that can be applied to the control algorithm to allow self control of the rotating speed and conveying speed according to the machining load.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.425-428
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• 1997

Effectiveness of corrective machining algorithm is verified experimentally in this paper by performing corrective lapping work to single side and double sides hydrostatic tables. Lapping is applied as machining method. Machining information is calculated from measured motion errors by applying the algorithm, without information on rail profile. It is possible to acquire 0.13pm of linear motion error, 1.40arcsec of angular motion error in the case of single side table, and 0.07pm of linear motion error, 1.42arcsec of angular motion error in the case of double sides table. The experiment is performed by the unskilled person after he experienced a little of preliminary machining. Experimental results show that corrective machining algorithm is very effective, and anyone can improve the accuracy of hydrostatic table by using the algorithm.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1793-1797
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• 2003

After the micro turning lathe was developed in the last year by AMR Laboratory in Yeungnam university, a micromilling machine is developed for micro/meso machining. This machine is integrated with PZT-driven micro-sliders, micro-linear encoders, aerostatic spindle which has maximum 150,000 rpm. It is applicable to milling and drilling of micro scale. This paper presents the possibility of micro/meso machining and characteristics of micro end milling process by using micro machine. A machining of micro parts using 0.2 mm flat end mill was achieved by micro-milling machine. Experimental results show the machining capability and positional accuracy of this machine is good enough for machining micro parts.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 금형가공 심포지엄
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• pp.239-244
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• 2002

In this study, we developed the manufacturing technology of micro-hole and micro-shaft for micro punching system using micro electrical discharge machining and micro electro chemical machining. Micro punching dies of tungsten carbide with $55\;{\mu}m\;and\;110\;{\mu}m$ diameter and $250\;{\mu}m$ depth were made by micro electrical discharge machining. The form accuracy and surface roughness of die hole were pretty good and it was shown that the punched hole quality was fine. WC micro-shaft with $30\;{\mu}m$ diameter was made by the multistep micro electro chemical machining. The developed technologies can be effectively used in precision manufacturing of micro punching die and mass production of micro-shaft.

• 한국정밀공학회지
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• 제21권3호
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• pp.83-90
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• 2004

This paper proposes a tool path generation method for machining impellers with 5-axis machining center. The shape of impeller is complex, being composed of pressure surface, suction surface and leading edge, and so on. The compound surface which is made of ruled surface such as pressure surface and suction surface and leading edge such as fillet surface, makes the tool path generation much complicated. To achieve efficient roughing, cutting area is divided into two region and then tool radius of maximum size that do not cause tool intereference is selected for shortening machining time. In finishing, accuracy is improved using side cutting for blade surface and point milling for leading edge.

• 한국기계가공학회지
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• 제18권10호
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• pp.42-47
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• 2019

Helical machining is an efficient method for machining holes using an endmill. In this study, a surface roughness prediction model was constructed for improving the productivity of hole machining. Experiments were conducted to form holes by the helical machining of AL6061-T4 aluminum sheets and correlation analysis was performed to examine the relationships between the variables based on the measured results. Meanwhile, a regression analysis technique was used to construct and evaluate the prediction model. Through these analyses, the parameter which has the greatest influence on the surface roughness when the hole is formed by the helical machining is the feed, followed by the number of revolutions of the endmill. Moreover, for the axial feed of the endmill, it was concluded that the influence of the surface roughness is small compared to the other two parameters but it is a factor worth considering to improve the accuracy when constructing the predictive model.

• 대한기계학회논문집
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• 제14권6호
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• pp.1495-1508
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• 1990

본 연구에서는 전류밀도와 가공시간을 변화시켰을 때의 가공량, 가공상태를 검토해 보았으며, 촉침홀더의 가공각도를 달리하거나 재부착문제를 해결하기 위한 마 스크의 사용여부에 따른 촉침의 가공상태를 알아보기 위해 초기선단반경 2$\mu\textrm{m}$, 선단각 90˚의 다이아몬드 촉침을 이온스파터 가공기를 사용하고, 가공조건을 변화시켜서 초 정밀 가공품의 표면거칠기 측정에 적합한 0.5$\mu\textrm{m}$ 이하의 미세한 선단반경을 갖는 촉침 을 가공하기 위한 가공조건에 대한 실험을 하였다.

• 한국생산제조학회지
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• 제25권3호
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• pp.211-216
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• 2016

Al alloys are useful materials having high specific strength and are used in machining of parts having thin-walled structures for weight reduction in aircraft, automobiles, and portable devices. In machining of thin-walled structures, it is difficult to maintain dimensional accuracy because machining deformation occurs because of cutting forces and heat in the cutting zone. Thus, cutting conditions and methods need to be investigated and cutting signals need to be analyzed to diagnose and minimize machining deformation and thereby enhance machining quality. In this study, an investigation on cutting conditions to minimize machining deformation and an analysis on characteristics of cutting signals when machining deformation occurs are conducted. Cutting signals for the process are acquired by using an accelerometer and acoustic emission (AE) sensor. Signal characteristics according to the cutting conditions and the relation between machining deformation and cutting signals are analyzed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1811-1815
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• 2003

Investigated is the relationship between tool deflection and geometrical accuracy in side wall machining. Form error is predicted directly from the tool deflection without surface generation. 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 manufacture. This study contributes to real time surface shape estimation and cutting process planning for the improvement of geometrical accuracy.