• 한국식품영양과학회지
• /
• 제39권7호
• /
• pp.1005-1010
• /
• 2010

본 연구에서는 인삼의 유용성분 강화 및 인삼 전근 활용을 위한 증숙 및 습식분쇄 조건을 조사하였다. 그 결과 무처리(A), $95^{\circ}C$/3 hr(B) 및 $121^{\circ}C$/15 min(C)의 증숙조건에 의해 각각의 당도는 7.7, 10.7 및 $11.2^{\circ}Brix$, 갈색도 0.37, 1.97 및 1.50로 증숙구간에서 당도 및 갈색도가 높게 나타났다. 조사포닌 함량은 7.19(A), 6.99(B) 및 8.83 mg/g(C)으로 C 조건에서 가장 높게 나타났다. 관능검사를 실시한 결과 C 조건에서 쓴맛 감소, 단맛 강도 및 전반적 기호도가 가장 높게 나타나 증숙처리 조건에서 관능적인 특성을 향상시킬 수 있었다. 가수량에 따른 습식분쇄 조건을 조사한 결과 가수량 300%에서 입자가 가장 작게 나타났다. 인삼의 습식분쇄조건은 분쇄 30분 및 3회에서 분쇄효율이 높았으며 평균입자크기는 $67.66\;{\mu}m$로 미세화되었다. 분쇄시간 및 횟수에 따른 유효성분 함량은 큰 차이가 없었다. 이상의 결과 증숙처리($121^{\circ}C$/15 min) 및 습식분쇄는 인삼의 전근 활용 및 유효성분 강화에 효과적인 것으로 확인되었다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
• /
• pp.677-680
• /
• 2008

저발열형 고로슬래그 시멘트의 초기강도 발현 특성을 향상시키기 위하여 낮은 분말도의 고로슬래그 분말과 보통 포틀랜드시멘트를 혼합 분쇄하여 입자 표면을 개질하였다. 사전 분쇄한 고로슬래그 분말의 비표면적은 $2535cm^2/g$(BS2), $3245cm^2/g$(BS3)의 2가지를 사용하였으며, 고로슬래그 분말과 시멘트를 진동밀에 투입하여 10분부터 30분까지 혼합 분쇄하여 표면을 개질하였다. 시멘트에 대한 고로슬래그 분말의 혼합비는 60$^{\sim}$80%의 3수준으로 변화시켰으며 혼합분쇄 후 비표면적의 변화, 입도분표, 시멘트의 수화열, 몰탈의 압축강도를 측정하였다. 시판 삼성분계 저발열 시멘트(LHC)와 비교시험 결과, 7일 압축강도발현의 100%이상과 72시간 누적수화열 170J/g 이하의 값을 만족하는 배합 및 혼합분쇄 시간을 찾을 수 있었으며 저분말도 고로슬래그를 다량으로 활용한 저발열 슬래그시멘트의 가능성을 확인하였다.

• 한국정밀공학회지
• /
• 제2권2호
• /
• pp.60-68
• /
• 1985

The Surface roughness is affected by the factors such as elements of grinding wheel, grinding conditions, and so on. Of all these factors, we studied surface roughness variation in accordance with grain size of grinding wheel and grinding depth of cut on the surface grinding. Tempered, annealed, quenched, and non-heat treated materials were used as specimen. The results obrained in these experiments are as follows: 1) The smaller the hardness is, the better the grinding surface roughness becomes. 2) Tempered materials after quenching shows the finest finished surface on grinding.

• 한국공작기계학회논문집
• /
• 제13권2호
• /
• pp.9-16
• /
• 2004

Because a generated heat during grinding operation makes a serious deformation on a ground surface as a convex form, a real depth of cut in deformed zone has larger than an ideal depth of cut. Consequently, the ground surface has a geometric error as a concave form after cooling the workpiece. In this study, the force and the geometric error of surface grinding were examined. From evaluating magnitude and mode of the geometric error according to grinding conditions, an optimal grinding condition was proposed to minimize the geometric error. In addiction the relationship between the geometric error and the grinding force was found out. Due to least square regression it was able to predict the geometric error by using the grinding force.

• 한국안전학회지
• /
• 제11권3호
• /
• pp.10-19
• /
• 1996

Grinding temperature and thermal deformation(dimensional error) are studied theoretically and experimentally. The propose of this research is clarified loading phenomena and residual stress In order to guide nozzle's efficiency. The main results to be obtained are as follows ; 1) When grinding condition Is high efficient grinding, FEM program is developed about grinding heat and dimensional error. 2) Thermal deformation depend on temperature distribution is in good agreement with experimental results in case of little grinding energy flux but is comparatively in good agreement with in case of large (3.5$\times$10$^{6}$ J/m). 3) In terms of high efficient grinding at field(table speed 4m/min), grinding fluid (dilution 5/100) obtained a good workpiece quality and decreased a grinding temperature. 4) A surface roughness, dimensional error, residual stress and loading phenomena with guide nozzle are decreased and these results obtained a good workpiece quality.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1994년도 춘계학술대회 논문집
• /
• pp.425-428
• /
• 1994

Non-uniform minute deformation of a cylinderical workpiece resulted from the heat treatment process prior to the grinding makes it diffeclt to control the approaching feedrate of a grinding wheelto a workpiece optimallywithout on-site detection of the grinding states in the plunge grinding. The 4-stage model of the plunge grinding process is proposed according to the state of contact between grinding wheel and workpiece ; precontact, partial contact, entire contact and spark-out. Despite of being scrious to the precision of workpiece finished, the duration of spark-out is determined empirically. The purpose of this research is to develop a monitoring/control system for saving non- production time and setting the optimal spark-out time based on sensor information in the plunge grinding using AE and ultra sonic sensor.

• 한국기계가공학회지
• /
• 제18권4호
• /
• pp.69-75
• /
• 2019

Since gasoline engines are based on a combination of a cast iron liner and an aluminum block, which have different thermal properties and stiffnesses, bore shape distortion is likely to occur during honing due to uneven thermal deformation. To solve this problem, many tests and evaluations are needed to support the development of a high-performance honing stone with low heat generation. Moreover, performance evaluation, which depends on inspection and observation after work, often requires much trial and error to optimize tool design, due to challenges in the accurate interpretation of results. This study confirmed that the assessment of grinding capability was clarified by evaluating performance under severe work conditions and by in-situ measurement and recording of current consumption (workload) and heat generation during operation. As a result of using a honing stone with excellent grinding performance in engine block manufacture-in which cylinder bore distortion caused by thermal deformation during manufacture is a problem-a noticeable improvement in the degree of cylindricity was observed.

• 소성∙가공
• /
• 제15권8호
• /
• pp.539-543
• /
• 2006

Experimental studies are carried out in order to investigate the effects of heat treatment on the surface machined by W-EDM. In this work, two ways of heat treatment after W-EDM are considered. As a comparison, the machined surface by a traditional method such as milling/grinding is also considered. Thereby, specimens are prepared by four different machining methods. Those are (1) milling and then grinding, (2) wire-cut electric discharge machining (W-EDM), and (3) low temperature heat treatment or (4) high temperature heat treatment after W-EDM. The resulting surface roughness are measured and the changes of surface microstructures are investigated using the scanning electron microscope (SEM) with energy dispersive X-ray spectrometer (EDS). In general, heat treatment after W-EDM result in smoother surface and better chemical composition at the machined surface. Especially, high temperature tempering could remove defects in the thermally affected zone, which cause an overall deterioration of the surface machined by W-EDM.

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

• International Journal of Precision Engineering and Manufacturing
• /
• 제8권3호
• /
• pp.24-44
• /
• 2007

Cylindrical grinding is one of the important metal cutting processes used extensively in the finishing operation of discrete components. The inherent high cutting temperature in grinding if not controlled may lead to rapid tool wear, which in turn will lead to dimensional inaccuracy. The very nature of the grinding mechanism in material removal impairs the grounded surfaces by inducing residual stress, micro cracks and other thermal damages at the machined surface. This paper is an attempt to review some of the surface integrity issues in cylindrical grinding taken up and reported by number of researchers over the years. This review may have been planned to be useful to the researchers and other professionals interested to work on grinding.