• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.899-902
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• 1997

The heat generated during surface grinding process can lead to elevate a grinding temperature, which cause the thermal damage to the workpiece material. Because of this reason, it is important to be able to predict the temperature which is occurred during grinding. The process parameters, therefore, should be adjusted properly to yield the acceptable workpiece temperature. In this study, we conducted an experimentation to obtain and also to analyze the temperature distribution of the workpiece with accordance in varying the grinding condition. For measuring the workpiece temperature, thermocouples of the CA type were inserted into the predetermined locations of the workpiece.

• 한국정밀공학회지
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• 제19권9호
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• pp.59-65
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• 2002

Grinding temperature between a grinding wheel and a workpiece surface, rising rapidly during a machining operation, has bad effects on a surface integrity such as the burning, the residual stress and the crack. In this study, the temperature distribution was obtained briefly by the finite element method and the grinding temperature of a workpiece varying with the grinding condition was measured experimentally. For obtaining the grinding temperature, a thermocouple method was applied. Three thermocouples were inserted in a surface of each workpiece. Changed grinding conditions were the depth of cuts, the feedrate, the dry and wet grinding, the up and down grinding and the number of pieces.

• 한국가스학회지
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• 제23권4호
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• pp.74-79
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• 2019

상용급 재가열로 내부 소재 온도 측정을 위하여 특수 제작된 시험용 시편을 사용하고, 실시간 온도 예측을 위하여 선형화 된 열모델이 적용되었다. 적용된 로는 Walking Beam Type이고 소재의 형상은 폭 160mm, 높이 160mm, 길이 8100mm의 STS302 재질이며 온도 측정을 위해 폭, 높이와 길이 방향으로 총 6개의 열전대를 설치하였다. 로내의 분위기 온도는 섭씨 1265도까지 상승시켰으며 소재의 장입부터 토출까지 약 2.5시간이 소요되었다. 시험결과, 토출 시 소재의 온도는 섭씨 1256~1259도 범위에서 평균적으로 1257도 였으며, 열모델을 통한 예측된 평균 온도는 1251도로 나타났다. 따라서 해석과 시험결과의 편차는 6도 정도로서, 이는 산업계에서 요구되는 10도 이내의 범위에 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.194-199
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• 1996

Grinding burn formed on the ground surface is related to the maximum temperature of workpiece surface and wheel temperature in the grinding process. The thermal characteristics of workpiece and grinding conditions on the surface temperature of the oxidation growing layer after get out of contact with the grinding wheel. The assumption used in grinding power signatures leads to the local temperature distribution between grinding wheel and workpiece, i.e., a single curve determines temperatures anywhere within the grinding wheel at anytime. This information is useful in the study of the grinding bum penetration into the wheel and thus provides an presentation of grinding trouble monitoring for the burning. On the basis of grinding power signatures in the wheel, thermally optimum conditions are defined and controlled. To cope with grinding burn, the use of grinding power signatures is an effective monitoring systems when occurring the grinding process. In this paper, the identified parameters suggested in this study which are derived from the grinding power signatures are presented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.19-23
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• 1995

The thermal deformation of a workpiece during grinding is one of the most important factors that affect a flatness of a grinding surface. The heat generated in one-pass surface grinding causes the convex deformation of a workpiece. Therefore, the ground durfae represents a concave profile. In the analysis a simple model of the temperature distribution, based on the results of a finite element method, is applied. Theanalyzed results are compared with experimental results in surface grinding. The main results obtained are as follows: (1) The temperature distribution of a workpiece by FEM has a good agreement with the experimental results. (2) The bending moment by generated heat causes a convex deformation of the workpiece and it leads to a concave profile of the grinding surface.

• 소성∙가공
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• 제18권8호
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• pp.616-624
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• 2009

In this work we demonstrate the hot-embossing process under different forming conditions such as forming temperature, load, and holding time in pressing, in order to determine the suitable conditions required for linear patterning on polymer plates (PC). Results showed that the replicated pattern depth increased in proportion to an increase in the forming temperature, load, and time. The reduction of the workpiece thickness increased according to the holding time in the pressing process. In the process of time, the reduction ratio of the workpiece thickness decreased due to the surface area increment of the workpiece, while the pressure on the workpiece declined. In order to reduce the bulging ratio we introduced a temperature difference between the upper and the lower punch.

• 소성∙가공
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• 제14권5호
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• pp.460-465
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• 2005

The temperature difference between die and workpiece has been frequently caused to various surface defects. The distribution and change for the temperature of forged part should be analyzed to prevent the generation of various defects related with the temperature. The surface temperature changes were affected with the interface heat transfer coefficient. Therefore, the coefficient is necessary to predict the temperature changes of die and workpiece. In this study, the experimental and FE analysis were performed to evaluate the coefficient with a function of pressure, temperature, material, and etc. The closed die upsetting was used to measure the coefficient on pressure over the flow stress. AISI1045, A16061, and Cu-OFHC were used to analyze the effect of material. The coefficient was increased with step-up of pressure between die and workpiece. And, A16061 was larger than that of the AISI1045 and Cu-OFHC up to the five times.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.122-126
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• 2004

The temperature difference between die and workpiece has been frequently caused to various surface defects. The distribution and change fur the temperature of forged part should be analyzed to prevent the generation of various defects related with the temperature. The surface temperature changes were affected with the interface heat transfer coefficient. Therefore, the coefficient is necessary to predict the temperature changes of die and workpiece. In this study, the experimental and FE analysis were performed to evaluate the coefficient with a function of pressure, temperature, material, and etc. The sealed die upsetting was used to measure the coefficient on pressure over the flow stress. AISI1045, Al6XXX, and Pure-Cupper were used to analyze effects according to the material. The coefficient was increased with step-up of pressure between die and workpiece. And, Al6XXX was larger than the AISI1045 and Pure-Cupper up to the five times.

• 에너지공학
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• 제26권2호
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• pp.23-31
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• 2017

열전달 및 에너지평형모델을 적용하여 연속식 가열로에서의 버너 배열에 따른 소재 및 노내 가스 온도의 영향을 수치해석으로 분석하였다. 연속식 가열로에서의 최적화된 소재의 가열구간을 확보하기 위해 한정된 공간을 갖는 노 내에서 총 공급열량을 동일한 조건으로 하고 가열능력에 따른 버너의 출력, 대수 및 배열 등을 조절하여 소재의 온도와 노 내 가스온도에 미치는 영향을 수치 해석적 방법으로 살펴보았다. 수치 해석적 방법을 통해 110톤/일의 생산량을 가지도록 설계된 기존의 가스 연소식 버너를 포함하는 연속식 가열로의 성능을 유지하면서 가스온도가 가열대 및 균열대의 중간지점에서 최대 값의 차이가 약 $40^{\circ}C$ 낮아 설비에 부하가 적고 소재목표 추출온도에 도달하는 $1,175^{\circ}C$조건의 버너배열을 도출하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.868-872
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• 1997

The thermal deformation of a workpiece during grinding is one of the most important factors that affect a flatness of a grinding surface. The heat generated in one-pass surface grinding causes the convex deformation of a workpiece. Therefore, the ground surface represents a conacve profile. In the analysis a simple model of the temperature distribution,based on the result of a finite element method, is applied. The analyzed results are compared with experimental results in surface grinding. The main results obtained are as follows; (1) The temperature distibution of a workpiece by FEM is comparatively in good agreement with the experimental results. (2) The bending moment by generated heat cause a convex deformation of the workpiece and it reads to a concave profile of the grinding surface.