• 한국재료학회지
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• 제9권1호
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• pp.18-24
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• 1999

This study was performed to observe the surface roughness and microstructural change of the grinding surface of plasma sprayed $Cr_2$$O_3$coating layer. The experimental condition were particle size of diamond grinding stone, depth of cut, rotating speed and coolant feed. As a results, the grinding conditions influencing on the surface roughness and microstructure were depth of cut and the particle size of diamond grinding stone. In addition to the conversion of brittle-ductile fracture of grinding surface on depth of cut is $5~10\mu\textrm{m}$ and rotating speed was 100 r.p.m after grinding

• 한국정밀공학회지
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• 제17권2호
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• pp.89-96
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• 2000

This paper describes the characteristic of die finishing to obtain smooth surface using electro-chemical grinding after cutting process. Electro-chemical grinding is possible under lower load and tool wear comparing with those in the mechanical grinding. Conventionally, if the metal bonding material of the grinding wheel is directly t contacted with workpiece, the current is circulated without electrolytic phenomena. Sometimes, electrical discharge is occurred between tool and workpiece. To cope with this problem, the metal-resin bonded pellet was used in this study. This pellet is composed of optimal volume of metal and resin powders and its characteristics are changable with the each volume of powders. Finally, high efficient die finishing is realized using metal resin bonded pellet in electro-chemical grinding.

• 한국정밀공학회지
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• 제17권6호
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• pp.192-198
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• 2000

This paper presents multi degree analysis of self-exited vibration of grinding system including spindle and workpiece rotational effect. The governing equations are derived by applying the finite element method to structure of spindle and workpiece rotor and by estimating the grinding force. Vibration analysis is carried out for external cylindrical plunge grinding. Displacement of workpiece and grinding force is simulated with machining time. Using this model, effects of characteristics of spindle bearing and major grinding conditions on chatter growth rate are predicted. Some of results are compared with those of other previous model and show good agreements.

• 한국정밀공학회지
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• 제14권3호
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• pp.21-27
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• 1997

This paper aims to clarify the effects of grinding conditions in form grinding of Sr-ferrite with the electro-plated diamond wheel. The main conclusions obtained were as follows. (1) The flexural strength and surface roughness of ferrite became the best at the peripheral wheel speed of 1700 m/min. (2) In the case of the depth of cut larger than 0.4mm, crack layers is induced in the ground surface, and the fracture type of chips exhibits slight ductile mode in the depth of cut smaller than 0.2mm. (3) Whe the depth of cut exceeds 0.6mm, the wheel life becomes extremely severe due to the large chipping and brack- age in the diamond grains. However, at the depth of cut .leq. 0.05mm, the diamond grain shows abrasive wear. (4) The decrease of flexural strength and the increase of surface roughness is in proportion to the increase of the feed rate. (5) Most effective nozzle setting angles with various delivery conditions of the grinding fluid, such as nozzle position .PHI. , flow rate Q, etc., were made clear.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.61-64
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• 1995

Grinding has been adapted as a finishing process,which can carry out form and surface integrity at the same time. Recently, high efficient and precise grinding technique is required bacause the needs for functional parts such as silicon wafer,ceramic,and electric materials are increasing. Accordingly, the development of grinding wheel appropriate to that purpose is very important. So, in this paper we newly developed a diamond grinding wheel by applying the superior characteristics of spheroidal graphite of the cast iron sintered product. Especially, a electric resistance sintering method was applied in which rapid heat treatment is possible. Finally, we have achieved successful results that the grinding wheel has high hardness,durability and grinding ability,and satisfies above conditions.

• 한국기계가공학회지
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• 제11권1호
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• pp.20-25
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• 2012

A Crankshaft multi grinding machine is developed for manufacturing of high precision crankshaft. The grinding head part of the developed machine should be moved precisely during grinding of work materials. In this paper, structural and modal analysis for the crankshaft multi grinding machine is carried out to check the design criteria of the machine. The analysis is carried out by FEM simulation using the commercial software. The machine is modeled by placing proper shell and solid finite elements. The results of structural and modal analysis confirmed that the structural characteristics of grinding machine and the structural safety are considered secure.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.405-409
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• 2003

We explored a new rough grinding technique on optics materials such as Zerodur. The facility used is a NANOFORM-600 diamond turning machine with a custom grinding module and range of diamond resin bond wheel. The grinding parameters such as workpiece rotation speed depth of cut and feed rate were altered while grinding the workpiece surfaces of 20m in diameter. Surface roughness is measured by Form Talysurf series2. Our target is to define grinding conditions producing the surface roughness better than 0.02${\mu}{\textrm}{m}$ Ra and the form accuracy of around 0.2${\mu}{\textrm}{m}$ PV.

• 한국기계가공학회지
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• 제4권1호
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• pp.13-17
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• 2005

We explored a new rough grinding technique on optics materials such as Zerodur. The facility used is a NANOFORM-600 diamond turning machine with a custom grinding module and a range of diamond resin bond wheel. The grinding parameters such as workpiece rotation speed, depth of cut and feed rate were altered while grinding the workpiece surfaces of 20mm in diameter. Surface roughness was measured by Form Talysurf series2. Our target is to define grinding conditions producing the surface roughness smaller than $0.2{\mu}m$ Ra.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.85-86
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• 2010

• 한국식품영양과학회지
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• 제41권11호
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• pp.1596-1602
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• 2012

국내에서 육종된 8가지 품종의 쌀을 습식과 건식제분하여 제분 방법에 따른 쌀가루의 품질변화를 품종별로 분석하고 이를 바탕으로 제분 방법에 비교적 민감하지 않고 일정한 품질의 가루를 생산할 수 있는 국내산 쌀 품종을 찾고자 하였다. 건식제분은 예상한 바와 같이 낟알의 경도가 높은 품종이 전분 손상도가 높았으나 습식제분에서는 Chenmaai와 같이 불린 쌀의 경도가 높더라도 전분의 손상도는 상대적으로 낮았다. 건식제분에 따른 손상 전분 함량의 증가는 쌀가루의 수분 흡수력을 급격히 증가시켰으며 습식제분은 낟알의 경도보다는 아밀로오스 함량에 따라서 수분 흡수력에 차이를 나타내었다. 가루의 수분 흡수력과 반비례하여 반죽의 질척한 정도가 나타나지만 고 아밀로오스 함량의 Suweon 517과 Milyang261은 제분 방법에 관계없이 수분 흡수력이 매우 높아서 빵이나 국수 등의 제품을 생산할 때 반죽에 더 많은 양의 물을 첨가해야 할 것으로 생각된다. 또한 건식제분된 가루가 습식제분된 가루에 비하여 수분 흡수력이 크기 때문에 반죽 과정에서 수분 첨가량을 증가시켜야 할 것이다. 건식제분은 품종 모두에서 최고 점도에 이르는 시간이 짧아지고 점도 붕괴가 증가하므로 습식 가루에 비하여 조리시간을 단축하고 호화 후 점도 조절이 필요하다. Hanareumbyeo, Manmibyeo, J insumi, Goamibyeo 등은 건식제분과 습식제분에 따른 호화 특성의 변화가 다른 품종에 비하여 크며, Suweon517과 Milyang261은 건식제분하면 setback 값이 증가하는 것으로 미루어 건식제분된 가루를 이용한 제품의 노화가 더 클 것으로 예측된다. 이상의 결과에 따라서 Chenmaai는 건식과 습식제분 모두에서 손상 전분의 함량이 낮고, 건식제분에 따른 수분 흡수율 증가가 적으며 제분에 따른 호화 점도 특성의 변화가 상대적으로 적어서 제분에 유리한 품종이다. 반면 Seolgaeng와 Suweon517은 낟알의 경도가 부드러운 분상질일지라도 건식과 습식제분 모두에서 손상전분 함량이 높고 수분 흡수력과 호화 점도의 특성 변화가 심하여 쌀가루로 분쇄하는 제분 적성이 좋지 않았다.