• 대한기계학회논문집A
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• 제24권2호
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• pp.338-346
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• 2000

Although the net-shape molding of composites is generally recommended, molded composites are frequently required cutting or grinding due to the dimensional inaccuracy for precision machine elements . During the composite machining operations such as cutting and grinding, the temperature at the cutting point may increase beyond the allowed limit due to the low thermal conductivity of composites, which might degrade the matrix of composite. Therefore, in this work, the temperature at the cutting point during cut-off grinding of carbon fiber epoxy composites was measured. The cutting force and surface roughness were also measured to investigate the cut-off grinding characteristics of the composites. The experiments were performed both under dry and wet grinding conditions with respect to cutting speed and feed rate. From the experimental investigation, the optimal conditions for the composite cut-off grinding were suggested.

• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.44-48
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• 1996

This paper describes the effects of thermal deformation in electromagnetic chuck on the grinding accuracy. Gringing process is the last machining process and decisive in saving past other machining cost. The thermal deformation of grinding machine is unavoidable and affect seriously ginding accuracy. The thermaldeformation of electromagnetic chuck is one of important thermal problems. Heat generation of magnetic chuck is analyzed and measured. The temperature disturibution in chuck is elliptical form with high temperature in center of chuck. The thermal deformation form of chuck is changed with time to mountain form. The grinding experiment shows that the thermal deformation of magnetic chuck influence strongly machining accuracy as much as the headstock

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.832-836
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• 1997

An experimental study on the grinding temperature, surface roughness and Acoustic Emission(AE) signal was conducted with different shapes of wheel. The grinding characteristics by slotted shapes of wheel changed by width and helical angle,were compared with those by general one. Lower grinding temperature was obtained for 30 .deg. helical angel with 10mm width and Root Mean Square(RMS) values of AE signals were lower for slotted shapes rather than general one. Surface roughness characteristic of slotted shapes found to be rough,but the value of roughness for 45 .deg. helical angel with 6mm width, represented to similar tendency general one.

• 한국생산제조학회지
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• 제9권6호
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• pp.65-70
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• 2000

Although the net-shape molding of composites is generally recommended, molded composites frequently requires cutting or grinding due to the dimensional inaccuracy for precision machine elements. During the composite machining operations such as cutting and grinding, the temperature at the grinding area may increase beyond the allowed limit due to the low thermal conductivity of composites, which might degrade the matrix of composite. Therefore, in this work, the temperature at the grinding point during surface grinding of carbon fiber epoxy composite was measured. The grinding temperature and surface roughness were also measured to investigate the surface grinding characteristics of the composites. The experiments were performed both under dry and wet grinding conditions with respect to cutting speed, feed speed, depth of cut and stacking angle. From the experimental investigation, the optimal conditions for the composite surface grinding were suggested.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 춘계학술논문집 2부
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• pp.821-823
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• 2011

본 논문에서는 초고온/고압의 환경에서 사용되는 메탈 구루부드 가스켓의 품질 및 생산성 향상 그리고 원가절감을 목표로 Gasket제작 전용기계시스템을 개발하여 제작기술혁신을 하고자 하였으며, 전용기계시스템의 구성은 그루부 가공전용기, 벤딩 전용기, 후열처리 전용기, 용접비드 황삭전용기, 용접비드 연삭전용기로 이루어져 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.145-150
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• 1992

화인세라믹의 우수한 공학적 특성으로 인한 최근의 이용가치 증대와 더불어 세라믹의 고정도 가공에 대한 관심이 높아지고 있다. 다이아몬드휠을 이용한 연삭이나 다이아몬드 공구를 이용한 선삭에 의해 세라믹의 고정도 표면생성을 실현시키고자 하는 연구가 활발히 진행되고는 있으나 아직 미흡한 상태에 있다. 따라서 전통적으로 고정도 표면생성에 널리 용되어 온 래핑에 의한 표면다듬질이 현재 행하여지고 있는 일반적인 방법이다. 본 연구에서는 화인세라믹의 고정도 표면생성을 위한 원통래핑 공정의 최적화 방법으로 실험계획법의 한 응용분야인 반응표면분석법을 이용하였으며 그 결과, 적은 재료와 시간으로 능률적이고 체계적인 실험 및 통계적인 분석을 통해서 원통세라믹의 고정도 표면생성을 위한 최적래핑조건을 찾아내었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.86-89
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• 2005

Design and estimation of a spindle system which was composed of grinding spindle and regulating spindle for the centerless grinding of ferrule was performed and prototypes of each spindle were manufactured. Loop stiffness of the spindle system was 130 N/${\mu}m$. Although the value was lower than the target value of 150 N/${\mu}m$, as there included 20% of the safety factor, it was enough to machine the ferrule. Rotational accuracies of each spindle were about 0.2${\mu}m$ at the primary speed of 2,300 rpm(grinding spindle) and 300 rpm(regulating spindle). Temperature rises at the same speed were about $4.4\;\~\;4.7^{\circ}C$ in the case of grinding spindle and $1.8^{\circ}C$in the case of regulating spindle, which were well agreed with the designed value. From these results, it was estimated that the prototype of spindle system had a enough performances for the centerless grinding machine to machine the ferrule.

• 한국정밀공학회지
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• 제22권11호
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• pp.142-150
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• 2005

Design and performance evaluation of a spindle system which was composed of a grinding spindle and a regulating spindle for the centerless grinding of ferrule were performed in this paper. Layout and details of spindle system were designed and hydrostatic bearings for spindles were also designed. Prototype of spindle system was developed and its availabilities to machine the ferrule were discussed using the experimental results on the spindle stiffness of each spindle, loop stiffness, rotational accuracy and thermal characteristics. Loop stiffness of the spindle system was $130\;N/{\mu}m$, which was enough to machine the ferrule. Rotational accuracies of each spindle were about $0.2{\mu}m$ at the primary speed of 2,300 rpm(grinding spindle) and 300 rpm(regulating spindle). Temperature rises at the same speed were about $4.4\~4.7^{\circ}C$ in the case of grinding spindle and $1.8^{\circ}C$ in the case of regulating spindle, which agreed well with the designed value. From these results, it was estimated that the prototype of spindle system had enough performances for the centerless grinding machine to machine the ferrule.

• 한국안전학회지
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• 제5권1호
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• pp.31-39
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• 1990

In this paper, the influence of the table speed, metal removal rate and grinding fluid on long wheel workpiece contact zone at high effect grinding was investigated by theoretical analyses and measuring the temperature, and discussed by the temperature distribution in grinding surface layer. Main results obtained are as follows, 1) Rega.dless of the table speed, the temperature gap of the workpiece(heat influx) is about 6-8 times as high in dry condition as in wet condition. 2) Good grinding condition can be obtained owing to the effect of grinding fluid without any burning defect under the condition of the metal removal rate(1.0mm$^3$/mm.s) in case of wet grinding. 3) When the depth from the surface layer is about 1.25-1.5mm under the condition of the slow table speed, surface temperature goes up higher as the table speed slows down, because long contact time is laked at the surface layer. 4) In case of the same metal removal rate, the lower the table speed becomes, the higher the surface temperature is, because grinding depth has a far more influence on wheel workpiece contact zone than the table speed.