• 한국생산제조학회지
• /
• 제9권2호
• /
• pp.96-101
• /
• 2000

In machining with cutting tool inserts having complex chip groove shape the flow curl and breaking pattern of the chip are different than in flat-face inserts. In the present work an effort is made to understand the three basic phe-nomena occurring in a chip since its formation in machining with groove type and pattern type inserts. These are the ini-tial chip flow the subsequent development of up and side curl and the final chip breaking due to the development of tor-sional and bending stresses. in this paper chip flow angle in a groove type and pattern type inserts. The expres-sion for chip flow angle in groove type and pattern type inserts is also verified experimentally using high speed filming techniques.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
• /
• pp.381-386
• /
• 1999

In machining with cutting tool inserts having complex chip groove shape, the flow, curl and breaking patterns of the chip are different than in flat-face type inserts. In the present work, an effort is made to understand the three basic phenomena occurring in a chip since its formation in machining with groove type and pattern type inserts. These are the initial chip flow, the subsequent development of up and side curl and the final chip breaking due to the development of torsional and banding stresses. In this paper, chip flow angle in a groove type and pattern type inserts. The expression for chip flow angle in groove type and pattern type insets is also verified experimentally using high speed filming techniques.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 춘계학술대회 논문집
• /
• pp.891-894
• /
• 2001

In this work, an effort is made to investigate the behavior of a chip, from its initial flow to its final breaking stage. The expression for chip flow in grooved tools is verified analytically using FEM. Cutting parameters like velocity and depth of cut have a profound influence on chip flow behavior. Chip curling increases and, for a given tool geometry, effectiveness of the groove increases with increasing depth of cut. The feasibility of tool design using FEM simulations is also demonstrated. Optimization of tool geometry results in better chip control.

• 한국정밀공학회지
• /
• 제18권11호
• /
• pp.101-106
• /
• 2001

In this work, an effort is made to investigate the behavior of a chip, from its initial flow to its final breaking stage. The expression for chip flow in grooved tools is verified analytically using FEM. Cutting parameters like velocity and depth of cut have a profound influence on chip flow behavior. Chip curling increases and, for a given tool geometry, effectiveness of the groove increases with increasing depth of cut. The feasibility of tool design using FEM simulations is also demonstrated. Optimization of tool geometry results in better chip control.

• 대한기계학회논문집
• /
• 제15권1호
• /
• pp.139-144
• /
• 1991

본 연구에서는 절삭가공시 생성되는 칩의 형상해석의 일환으로 2차원 절삭시 칩은 절삭날에 수직한 방향으로 공구경사면을 흘러간다는 기본적인 전제조건과 Kluft 등의 칩흐름각 예측에 대한 제안중 노으즈반경(nose radius) 및 기울임각의 영향을 중 첩시키고, 또한 절삭날에 연하여 미변형 칩두께(undeformed chip thickness)가 달라지 는 경우 칩흐름의 세기는 이에 비례한다는 Baart등의 가정을 도입하여 칩흐름각에 대 한 새로운 해석을 시도하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
• /
• pp.481-485
• /
• 1987

The fabrication of a micro mass flow sensor on a silicon chip by means of micro-machining technology is described on this paper. The operation of micro mass flow sensor is based on the heat transfer from a heated chip to a fluid. The temperature differences on the chip is a measure for the flow velocity in a plane parallel with the chip surface. An anisotropic etching technigue was used for the formation of the V-type groove in this fabrication. The micro mass flow sensor is made up of two main parts ; A thin glass plate embodying the connecting parts and mass flow sensor parts in silicon chip. This sensor have a very small size and a neglible dead space. Micro mass flow sensor can fabricate on silicon chip by micro machining technology too.

• 한국정밀공학회지
• /
• 제5권1호
• /
• pp.84-93
• /
• 1988

The on-line detection of the chip flow is one of the most important technologies in com- pletly automatic operation of machine tool, such as FMS and Unmanned Factories. This problem has been studied by many researchers, however, it is not solved as yet. For the recognition of chip flow in this study, the dynamic cutting force components due to the chip breaking were measured by dynamometer of piezo-electric type, and the frequency components of cutting force were also analyzed. From the measured results, the effect of cutting conditions and tool geometry on the dynamic cutting force component and chip formation were investigated in addition to the relationships between frequency of chip breaking (fB) and side serrated crack (fC) of chip. As a result, the following conclusions were obtaianed. 1) The chip formations have a large effect on the dynamic cutting force components. When chip breaking takes place, the dynamic cutting force component greatly increases, and the peridoic components appear, which correspond to maximum peak- frequency. 2) The crater wear of tool has a good effect on the chip control causing the chiup to be formed as upward-curl shape. In this case, the dymamic cutting force component greatly increases also 3) fB and fC of chip are closely corelated, and fC of chips has a large effect on the change of the situation of chip flow and dynamic cutting force component. 4) Under wide cutting conditions, the limit value (1.0 kgf) of dynamic cutting force component exists between the broken and continuous chips. Accordingly, this value is suitable for recognition of chip flow in on-line control of the cutting process.

• 전기학회논문지
• /
• 제56권3호
• /
• pp.561-565
• /
• 2007

We propose glass and PDMS (polydimethylsiloxane) chips for DNA amplification with continuous-flow PCR (polymerase chain reaction). The PDMS microchannel was fabricated using a negative molding method for sample injection. Three heaters and sensors of ITO (indium-tin-oxide) thin films were fabricated on glass chip. ITO heaters and sensors were calibrated accurately for the temperature control of the liquid flow. ITO heater generated stable heat versus applied power. ITO sensor resistance was changed linearly versus temperature increase as a RTD (resistance temperature detector) sensor. As a result, we enable precision temperature control of continuous-flow PCR chip. Using the continuous-flow PCR chip DNA plasmid pKS-GFP 720 bp was successfully amplified.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 춘계학술대회논문집
• /
• pp.427-733
• /
• 2003

Adiabatic shear bands have been observed in the serrated chip during high strain rate metal cutting process of medium carbon steel and titanium alloy. The recent microscopic observations have shown that dynamic recrystallization occurs in the narrow adiabatic shear bands. However the conventional flow stress models such as the Zerilli-Armstrong model and the Johnson-Cook model, in general, do not predict the occurrence of dynamic recrystallization (DRX) in the shear bands and the thermal softening effects accompanied by DRX. In the present study, a strain hardening and thermal softening model is proposed to predict the adiabatic shear localized chip formation. The finite element analysis (FEA) with this proposed flow stress model shows that the temperature of the shear band during cutting process rises above 0.5T$\sub$m/. The simulation shows that temperature rises to initiate dynamic recrystallization, dynamic recrystallization lowers the flow stress, and that adiabatic shear localized band and the serrated chip are formed. FEA is also used to predict and compare chip formations of two flow stress models in orthogonal metal cutting with AISI 1045. The predictions of the FEA agreed well with the experimental measurements.

• 소성∙가공
• /
• 제12권4호
• /
• pp.358-363
• /
• 2003

Adiabatic shear bands have been observed in the serrated chip during high strain rate metal cutting process of medium carbon steel and titanium alloy The recent microscopic observations have shown that dynamic recrystallization occurs in the narrow adiabatic shear bands. However the conventional flow stress models such as the Zerilli-Armstrong model and the Johnson-Cook model, in general, do not predict the occurrence of dynamic recrystallization (DRX) in the shear bands and the thermal softening effects accompanied by DRX. In the present study, a strain hardening and thermal softening model is proposed to predict the adiabatic shear localized chip formation. The finite element analysis (FEA) with this proposed flow stress model shows that the temperature of the shear band during cutting process rises above 0.5Τ$_{m}$. The simulation shows that temperature rises to initiate dynamic recrystallization, dynamic recrystallization lowers the flow stress, and that adiabatic shear localized band and the serrated chip are formed. FEA is also used to predict and compare chip formations of two flow stress models in orthogonal metal cutting with AISI 1045. The predictions of the FEA agreed well with the experimental measurements.s.