• Journal of the Korean Wood Science and Technology
• /
• 제16권4호
• /
• pp.61-69
• /
• 1988

Recently the automization of wood manufacturing and the development of CNC machine tools becomes the center of interest. Cutting mechanism, tool wear and the roughness of machined surface have been studied. In the studies about wood for special uses, concrete data of cutting is desired. While Pinus densiflora is characterized that heartwood develops as age increases, Chunyang District has the characteristic of strength, red color, relatively regular chap and high heartwood - percentage. But there is no data about cutting this wood, Chunyang District. In this study face milling by sintered carbide tool was excuted to Chunyang District. Cutting force, Surface roughness and states were investigated with regard to cutting speed. Example results were as follows; 1) Mean cutting resistance against lateral component force and longitudinal component force decreased rapidly up to cutting speed of 155 m/min, and remains constant above this speed. 2) The surface roughness of cutting surface lowered as cutting speed increased, regardless of fiber formation. Radial rougness of fiber is larger than lineal surface roughness. 3) Increase in Cutting speed made machining mark restrained. Down-milling showed larger marks than up-milling.

• 대한기계학회논문집
• /
• 제10권1호
• /
• pp.131-137
• /
• 1986

본 논문에서는 도포하기가 용이한 극성유기물질인 magic ink( $C_{6}$ $H_{5-}$ CH/13+ $C_{6}$ $H_{4}$(C $H_{3}$)$_{2}$+ $C_{4}$ $H_{9}$OH+ $C_{6}$ $H_{12}$ $O_{2}$) 를 Rehbinper 효과가 큰 동에 도포하고, 공구경사각을 변화시켜 매 절삭깊이마다 반복 2차원절삭을 실시하여 절삭기구, 절삭저항의 변화, 전단면의 전단변형율, 전단에너지 및 마찰에너지등의 변화를 상호관련시켜 분석하므로서 절삭성의 향상원인을 규명코저 한다.다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2010년도 추계학술대회 초록집
• /
• pp.41.2-41.2
• /
• 2010

최근 태양전지 제조비용 절감을 위해 초박형 실리콘 태양전지 개발이 활발히 이루어지고 있다. 이에 따라 후면전계(Back Surface Field, BSF) 특성에 대한 관심이 높아지는 추세이다. 이에 본 연구에서는 후면의 결정방향 및 표면구조에 따라 형성되는 후면전계(BSF)의 특성에 대해 알아보고자 하였다. 후면이 절삭손상층 식각(Saw damage etching) 후 (100)면이 드러난 실리콘 기판과 텍스쳐링(Texturing) 후 (111)면이 드러난 실리콘 기판에 후면 전극을 스크린 인쇄 후 Ramp up rate을 달리 하여 소성 공정(RTP system)을 통해 후면전계(BSF)를 형성하여 비교하였다. 후면전계(BSF)의 형상과 특성만을 평가하기 위하여 염산을 이용하여 후면 전극층을 제거하였다. 후면 전극 제거 후 주사전자현미경(Scanning Electron Microscopy)과 3차원 미세형상측정기(Non-contacting optical profiler)로 후면전계(BSF)의 형상을 비교하였다. 또한 후면전계(BSF)의 특성을 평가하고자 Quasi-Steady-State Photo Conductance(QSSPC)를 사용하여 포화전류(Saturation current, $J_0$)을 측정하였고, 면저항 측정기(4-point probe)로 면저항을 측정하여 비교하였다. 후면 전계(BSF)는 (100)면과 (111)면에서 모두 Ramp up rate이 빠를수록 향상된 특성을 보였고, (111)면에서 더 큰 차이를 보였다.

• 한국생산제조학회지
• /
• 제8권5호
• /
• pp.102-107
• /
• 1999

In this paper hardened SCM440 material and annealed SCM440 material are for cutting experiments by the cutting con-dition which is chosen respectively by tool three components of cutting force are recorded using multicorder, Then the surface roughness for various force are measured by Roughness Tester. The results of the experiment are summarized as follow. The hardened material cut by ceramic tool(BX20) gives the highest radial component values among the cutting resistance radial components is increased higher for the higher cutting speed even though vertical component and axial component tend to decrease. But when the annealed material was cut increase in cutting speed results in the increase of three component forces. Since ceramic insert tip used the experiment hardly affect Built-up Edge and heat the cutting resistance decrease slightly regardless of the increased of cutting speed. The hardened material has higher three compo-nent force value than the annealed material because the material of high hardness is increased cutting resistance. The low-est cutting forces for hardened material and annealed material are shown in the cutting speed of 60m/min and 180m/min. respectively.

• Journal of the Korean Wood Science and Technology
• /
• 제27권1호
• /
• pp.56-63
• /
• 1999

국산 죽재를 목재산업용 원재료로 활용할 수 있는 가능성을 타진하기 위하여 대표적인 우리나라 대나무 수종인 전남 담양산 맹종죽, 분죽 및 왕대의 절삭과 건조특성 등 기계가공성을 조사, 분석하였다. 연구 결과 쪼개기저항은 공구가 2.5cm 피삭재 내부로 진입하였을 때 최대로 상승하였으며, 칼날각 15도의 쐐기형 공구를 이용하면 쪼개기저항을 최소화할 수 있는 것으로 밝혀졌다. 또한 둥근톱과 띠톱에 의한 죽재의 절삭면 품질은 목재의 경우에 비하여 비교적 양호하였다. 한편 두께 12mm 맹종죽을 함수율 60%에서 10%까지 온도 $70^{\circ}C$로 건조하는데 약 62.5 시간이 소요되었다.

• 한국기계가공학회지
• /
• 제19권11호
• /
• pp.23-28
• /
• 2020

In general, lithography techniques are applied when machining single-crystal silicon in nanoscale applications; however, these techniques involve low degrees of freedom for the vertical shapes. By applying mechanical techniques to machine silicon, nanopatterns having various types of vertical shapes can be manufactured. In this study, we determined the ductile-brittle machining transition point and analyzed the- variation of the specific cutting resistance within the ductile machining region in nanoscale applications. When brittle fracture occurred during the nanoscale cutting, the depth of cut and cutting force increased and decreased rapidly, respectively. The first point of rapid increase in the depth of cut was defined as the ductile-brittle machining point. Subsequently, the shape of the machining tool was observed using a scanning electron microscope to calibrate the machining area, considering the tip blunting. The specific cutting resistance decreased continuously and converged to a certain value during the nanoscale cutting. The decrease and convergence in the value can be attributed to the decrease in the ratio of the arc length to the area of the machining tool and silicon.

• 대한기계학회논문집
• /
• 제13권4호
• /
• pp.604-610
• /
• 1989

본 연구는 알루미나계 세라믹의 소결 다이아몬드 공구로 절삭시의 칩의 형태 와 절삭저항을 관찰하였다. 절삭 양식은 건식과 습식으로 하고, 여러 가지 적삭조건 에 따른 flank 마멸의 진행과정, 가공면의 표면거칠기에 미치는 영향 및 가공면의 크랙 상태를 조사형 현미경으로 확대 검출하여 가공상태를 정밀하게 조사, 측정하였 다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.129-132
• /
• 2003

Used cutting fluid from machining processes is harmful to both environment and human health. Chemical substances that provide the lubrication function in the machining process are toxtc to the environment if the cutting fluid is released to soil and water and caused serious health problems to workers who are exposed to the cutting fluid in both liquid and mist form. Recently. cost of using cutting fluid is increasing as the number and the extensiveness of environmental protection laws and regulations increase. Therefore, the use of cutting fluid in machining processes place an enormous burden on manufacturing companies to cover the additional costs associated with their use and protection of our environment. Current trends in manufacturing are focused on minimizing or eliminating the use of metalworking fluids in machining processes. And the increased costs for the disposal of waste products (swarf, coolants and lubricants), especially in industrially developed countries, has generated interest in dry machining. A variety of new techniques are testimony that new technology has rationalized further efforts to research and implement dry machining processes. This paper presents the developed equipment, the process optimization and the applications in the field of surface grinding for the new cryogenic dry machining using a compressed cooling air. The investigated new machining process method shows many advantages compared to conventional techniques with cutting fluid.

• 한국생산제조학회지
• /
• 제8권5호
• /
• pp.47-53
• /
• 1999

The purpose of this study was to determine the effects of various cutting condition on the cutting resistance and surface roughness of material in turning operation using a coated carbide tool. The workpiece materials were the carbon steel SM20C and SM45C The results of this study are summarized as follows: The cutting force decreases as the feedee amount and the cutting depth decrease and the cutting speed increases. In order to obtain a proper surface roughness to each material it is desirable to set the feeding amount as 0.059mm.rev, the cutting depth as 0.4mm and the cutting speed as 270m/min for SM20C, while setting the feeding as 0.059mm/rev the cutting depth as 0.6mm and the cutting speed as 270m/min for SM45C.

• 한국생산제조학회지
• /
• 제9권5호
• /
• pp.157-164
• /
• 2000

A machine tool generally has some serious stability problems in the form of tool chatter during the cutting process. Chatter vibration deteriorates the surface finish, reduce tool and machine life, accelerates machine tool system component wear, and may lead to an unacceptable noise sound in the working environment. In this study, the behavior of spectral density of AE signal and principal cutting force signal in order to monitor the chatter vibration in the cutting process has been investigated. From the results, the reliability of proposed monitoring method has been confirmed.