• 한국가구학회지
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• 제11권1호
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• pp.61-68
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• 2000

This study was carried out to investigate the effect of grain and veneer thickness on drying rate, required energy consumption, and drying defects such as checking, end waving, and burning during a far-infrared radiation drying process of decorative veneers of hard maple and beech. Most of the veneer could be dried from green to in-use moisture content within 30 to 360 seconds. The drying rates were significantly affected by veneer thickness, but there was little difference between edge-and flat-sliced veneers. The formation of checking during drying test was none or very slight. The percentages of the veneers defected by checks were higher in the flat-sliced veneers than in the edge-sliced veneers. The maximum end wavinesses in the flat-sliced veneers were almost 1.6 to 3 times larger than that in the edge-sliced veneers. All veneers were fee from burned marks during drying test.

• 대한기계학회논문집
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• 제9권5호
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• pp.590-597
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• 1985

본 논문에서는 위치오차는 가공전 밀링베드를 수치제어 장치를 이용하여 가공 면에 수직한 방향으로 움직여 수치제어 장치인 스텝모우터의 분해능 한계 내에서 보정 하고 또한 공구휨에 상당하는 만큼 이 송속도를 더함으로써 제어하며, 파형오차는 이 송속도와 공구처짐 사이의 관계를 수정된 Taylor의 공구식으로 모형화하고 절삭공정중 이송속도를 적절히 조절하여 공구의 휨양을 제어함으로써 스텝모우터를 갖는 밀링머시 인에서 길이 508mm,두께 20mm의 두꺼운 철판을 평면절삭하는 경우 직진도오차를 최소 로 하는 GAC 방법을 개발하였다.측정은 밀링머시인 자체의 구조적, 동적변화나 절삭 조건의 변화, 공구의 재질 및 마멸상태의 변화, 공작물의 재질 변화등에 적응할 수 있 도록 Fig. 2에 보인 바와 같이 등간격으로 배열된 100개의 위치에서 가공후(post-pro- cess)측정을 통하여 취하였고, 절삭계수의 추정은 측정점을 각각 10개씩 10개의 구간 으로 묶어 각 구간에서의 계의 특성이 변하지 않는다는 가정하에서 계수를 지수가중 반복최소 자승(exponentially weighted recursive least squares, EWRLS)법을 이용하 여 추정하였고, 실제 절삭작업중 모델의 계수변화에 대한 사전 지식이 없이도 이들 계 수들을 보정시킴으로써 최적의 직진도를 얻을 수 있는 절삭조건을 제시하였다. 그리 고 이 방법의 도입으로 단일(SINGLE-PASS)밀링작업이 가능함을 보였고 또한 방법의 타 당성을 증명하기 위하여 여러 경우의 절삭상태에서 실험을 수행하였다.

• Journal of the Korean Wood Science and Technology
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• 제25권4호
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• pp.22-28
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• 1997

This research was carried out to obtain the fundamental data for the development of the technology and practical use of far-infrared radiation(IR) drying of quarter-sliced decorative veneers of walnut and red oak. The average drying rates of IR drying were about one and half to four times those of kiln drying and this tendency was prominent in thin veneer. The end wavinesses of the IR-dried veneers were smaller than those of kiln-dried veneers. These were largely recovered by the cold treatments after drying. The consumed electric power for IR drying was about one-fifth to two-fifthes compared to that for kiln drying.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.155-160
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• 2002

Recently, the development of aerospace and automobile industries has brought new technological challenges, rebated to the growing complexity of products and the new geometry of the models. High speed milling with a 5-Axis milling machine has been widely used fur 3D sculptured surface parts. When turbine blades are machined by a 5-axis milling, their thin and cantilever shape causes vibrations, deflections and twists. Therefore, the surface roughness and the waviness of the workpiece are not good. In this paper, the effects of cutter orientation and the lead/tilt angle used to machine turbine blades with a 5-axis high speed ball end-milling were investigated to improve geometric accuracy and surface integrity. The experiments were performed using a lead/tilt angle of 15$^{\circ}$ to the workpiece with four cutter directions such as horizontal outward, horizontal inward, vertical outward, and vortical inward directions. Workpiece deflection, surface roughness and the machined surface were all measured with various cutter orientations such as cutting directions, and lead/tilt angle. The results show that the best cutting strategy for machining turbine blades with a 5-axis milling is horizontal inward direction with a tilt angle.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 금형가공 심포지엄
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• pp.53-60
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• 2002

Recently, the development of aerospace and automobile industries brought new technological challenges, related to the growing complexity of products and new geometry models. High speed machining using 5-Axis milling machine is widely used for 3D sculptured surface parts. 5-axis milling of turbine blade generates the vibration, deflection and twisting caused from thin and cantilever shape. So, the surface roughness and the waviness of workpiece are not good. In this paper, The effects of cutter orientation and lead/tilt angle in 5-Axis high speed ball end-milling of turbine blade were investigated to improve the geometric accuracy and surface integrity. The experiments were performed at lead/tilt angle $15^{\circ}$ of workpiece with four cutter directions such as horizontal outward, horizontal inward, vertical outward, and vertical inward. Workpiece deflection, surface roughness and machined surface were measured with various cutter orientations such as cutting direction, and lead/tilt angle. The results show that when 5-axis machining of turbine blade, the best cutting strategy is horizontal inward direction with tilt angle. The results show that when 5-axis machining of turbine blade, the best cutting strategy is horizontal inward direction with tilt angle.

• 한국산학기술학회논문지
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• 제15권4호
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• pp.1871-1878
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• 2014

폴리메틸메타클릴레이트(PMMA)는 광 관련 부품제조에 있어 중요한 재료로 많이 사용되고 있다. 특히 TV, 모니터, 휴대폰 등에 쓰이고 있는 디스플레이의 도광판(Light Guide Panel)에 적용되고 있어 현재까지는 매우 큰 상업적인 수요가 있다. PMMA 도광판의 가공은 일반적으로 고속밀링에 의해 이루어지는데 부품에 대한 높은 정밀도 요구특성에도 불구하고 가공표면의 굴곡, 균열 등에 대한 불량이 적지 않게 발생하고 있다. 이러한 문제점을 해결하기 위하여 PMMA 진동을 부가하는 고속선삭의 적용이 시도되었으며 절삭공구에 진동을 부가하기 위한 장치와 최적 조건이 조사되었다. 도광판용 PMMA의 진동절삭은 일반적인 밀링가공법에 비해 절삭력의 현저한 감소, 열변형영역의 축소 등을 유도하였다. 가공면에 있어서는 가공방법이 엔드 밀링에서 단인공구를 사용하는 선삭으로 변경되었음에도 불구하고 진동절삭법에 의해 가공표면의 균일성이 크게 향상되어 가공면의 표준편차 $1.0{\sim}6.0{\mu}m$, 평균거칠기 $0.3{\mu}m$가 달성되었다.