• Journal of Biosystems Engineering
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• 제24권3호
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• pp.259-266
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• 1999

This research was carried out to investigate the possibility of real time rice milling ratio measurement using the spectral reflection characteristics. In this study, various methods were compared such as \circled1 using the whiteness meter, \circled2 using the colorimeter, \circled3 using the Visible and the NIR reflection spectrum. The samples were milled in the domain of 84~96% by 0.5% interval classified by milling ratio. The NMG treatment method required about 20 minutes to determine the milled ratio and r2 was 0.0028 to 0.7959 that was very low. In case of whiteness meter, r2 was high but speed of measurement was 5 minutes that was very low. Measurement with the colorimeter required about 5 minutes and r2 was 0.60 to 0.85 that was low. The reflection spectrum were measured in the range of 400~2,500nm with 2nm interval and the MLR model with six-wavelength obtained from first derivative of spectra gave the best results(r2 = 0.967, SEP = 0.729%)

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.895-898
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• 2001

This paper presents an optimization cutting speed(OCS) program developed to improve the machining precision and tool life in high speed machining using ball end milling. This program optimized the cutting speed that is changing at any time in free surface machining of an automobile part like a connecting load die. The technique of optimization cutting speed makes the CAD/CAM-generated NC code go through a reverse post process, conducts cutting simulation, and obtain the effective tool diameter of the ball end milling. Then it changes the spindle revolution to within the range of critical cutting speed fit for the material of the workpieces depending upon the effective tool diameter. In this study, the machining precision and tool life were compared for the two connecting load dies processed using the general cutting method and the proposed optimization cutting speed technique, respectively.

• 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.

• 한국정밀공학회지
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• 제12권11호
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• pp.63-73
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• 1995

A mechanistic force system model considering the flank wear for the face milling process has been developed. The model predicts variation of the cutting forces according to flank wear in face milling over a range of cutting conditions, cutter geometries and cutting process geometries including relative positions of cutter to workpiece and rounouts. Flycutting and multitoth cutting teste were conducted on SS41 mild steel with sintered carbide tool. In order to verify the mechanistic force model considering the flank wear of cutting tools, a series of experiments was performed with single and multitooth cutters in various cutting conditions. The results show good agreement between the predicted and measured cutting force profiles and magnitudes in time and frequency domains.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 동계학술연구발표회 및 스핀트로닉스와 나노물리에관한 국제심포지움
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• pp.44-45
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• 2007

We have studied the formation of alloy for $Ni_{45}AL_{45}C_{10}$ as a function of milling times. This alloy was produced using mechanical alloying. The effect of milling time on local structural changes of $Ni_{45}AL_{45}C_{10}$ has been investigated by means of EXAFS. Both XRD and EXAFS patterns from mechanically alloyed $Ni_{45}AL_{45}C_{10}$ powder indicates the formation of solid solution. The variation of lattice parameter and particle sizes could be analyzed from the different of milling times. Magnetization was also measured by using VSM.

• 한국세라믹학회지
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• 제32권7호
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• pp.853-857
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• 1995

ZrSiO4 powders were prepared from partially hydrolyzed solution of Si(OC2H5)4 and ZrOCl2.8H2O solution by the sol-gel method and formation rate of ZrSiO4 on the reaction parameter was investigated. In order to prepare homogeneous ZrSiO4 precursor gels, the H2O/Si(OC2H5)4 molar ratio of about 2, the pH of the ZrOCl2.8H2O solution fo about 4 and stirring time of the mixed solutions of about 2 hrs were appropriate. Formation of temperature of ZrSiO4 reduced about 15$0^{\circ}C$ by milling and formation of ZrSiO4 at 1300~135$0^{\circ}C$ showed an accelerative increase through the hedvall effect by silica.

• 한국가정과학회지
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• 제5권2호
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• pp.33-43
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• 2002

This study was investigated textural properties of Injulmi affected by milling methods, varieties and added water volume. Sinsunchalbyeo and Hwasunchalbyeo flours were made using Rin-dry milling(PDM) and roll-wet milling(RWM) methods. The proximate composition of waxy rice starches and waxy rice flours were similar. Water binding capacity, soluble carbohydrate and damaged starch of waxy rice flour by RWM: were higher than those of waxy rice flours by PDM. By increasing added water volume, hardness and adhesiveness of Injulmi were decreased. By increasing storage time, hardness of Injulmi was increased, but adhesiveness was decreased. The hardness of Injulmi made from waxy rice flours by PDM was higher than by RDW.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 춘계학술대회 논문집
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• pp.18-23
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• 1996

The Job of Milling in the Local Skill Contest in 1996 was to assemble parts into a complete whole of the parts number 1, 3, 4 worded by Milling Machine and the parts number 2 worked by Machining Center. In the parts of Milling Machine, the Job was to work 45$^{\circ}$angle working, T-slot, dovetail, the correct position drilling, rimming, boring, etc. In the Machining Center, there were the way of calculation of point of contact of 'R' contour curved line and lots of working elements. So, it was possible to work the parts and assemble them within the time limit only through the program to be made out in the way to shorten working hours.

• 한국정밀공학회지
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• 제21권9호
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• pp.41-47
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• 2004

As mechanical structures are minimized, the demand on micro dies and molds has increased. Machining complex 3D shapes requires fabrication procedures for preparing the electrodes. Micro electrical discharge milling using a simple shape electrode can produce 3D micro structure. In this paper the machining characteristics of micro electrical discharge milling according to depth of cut and capacitance are investigated. The machining time is diminished when simple tool-paths and algorithms for changing the feedrate are applied. But a distorted bottom shape and a tapered wall shape are inevitable after machining. The distorted bottom shape and the taper angle of wall are reduced by finish machining.

• 한국결정성장학회지
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• 제16권3호
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• pp.101-105
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• 2006

본 연구에서는 planetary milling을 사용하여 Ti 분말과 $Si_3N_4$와의 반응이 일어나도록 하여 nano $TiN_x$을 제조하였다. 이렇게 얻어진 분말은 Ti 분말과 혼합하여 SPS 소결 장치를 이용하여 소결하였으며 이 소결체의 고온에서의 경도변화를 조사하기위해 $850^{\circ}C$에서 열처리하였다. 분말의 물성평가는 X선 회절분석을 통해 결정상의 변화를 분석하였으며, 그 결과 milling 시간이 10시간의 milling에서는 $TiN_{0.26}$과 TiN이 혼재되어 있으며 20시간의 milling에서는 주로 TiN이 생성되는 것으로 확인되었다. 제조된 분말의 표면관찰을 통해서는 milling 시간이 증가할 수로 입자표면에 새로 형성된 반응물 size 분포를 조사하였으며, milling 시간이 길수록 입자표면의 $TiN_x$ 입자의 사이즈가 $10{\sim}20nm$ 정도로 작아지는 것을 알 수 있었다. Ti와 $TiN_x$를 중량비로 50:50로 혼합하여 제조한 소결체의 경도는 마이크로비커스 경도 값으로 $1050kgf/mm^2$ 정도를 나타내었다.