• 한국정밀공학회지
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• 제21권11호
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• pp.38-45
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• 2004

This paper discusses the minimum cutting thickness with a continuous chip in sub-micrometer order precision diamond cutting. An ultra precision cutting model is proposed, in which the tool edge radius and the friction coefficient are the principal factors determining the minimum cutting thickness. The experimental results verify the proposed model and provide various supporting evidence. In order to reduce the minimum cutting thickness a vibration cutting method is applied, and the effects are investigated through a series of experiments under the same conditions as conventional cutting method.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.376-381
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• 2003

Ultra precision diamond cutting is a very efficient manufacturing method for optical parts such as HOE, Fresnel lenses, diffraction lenses, and others. During micro cutting, the rake angle is likely to become negative because the tool edge radius is considerably large compared to the sub-micrometer-order depth of cut. Depending on the ratio of the tool edge radius to the depth of cut, different micro-cutting mechanism modes appear. Therefore, the tool edge sharpness is the most important factor affecting the qualities of machined parts. That is why diamond especially mono-crystal diamond, which has the sharpest edge among all other materials is widely used in micro-cutting. The question arises, given a diamond tool, what is the minimum (critical) depth of cut to get continuous chips while in the cutting process\ulcorner In this paper, the micro machinability around the critical depth of cut is investigated in micro grooving with a diamond tool, and introduce the minimizing method of cutting depth using vibration cutting. The experimental results show the characteristics of micro cutting in terms of cutting force ratio (Fx/Fy), chip shape, surface roughness, and surface hardeing around the critical depth of cut.

• 오토저널
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• 제14권6호
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• pp.113-126
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• 1992

Recently the multi-kind, small-amount manufacturing system has been replacing the mass manufacturing system, and domestic machining inustry also is eager to absorb the new technology because of its high productivity and cost reduction. The optimization of the cutting condition has been a vital problem in the machining industry, which would help increase the productivity and raise the international competitiveness. It is intended in this study to investigate the machining costs per unit time which is essential to the analysis of the optimal cutting condition, to computer the cutting speed that lead to the minimum machining costs and the maximum production to suggest the cutting speed range that enables efficient speed cutting, and to review the machining economy in relation to cutting depth and feed. Also considered are the optimal cutting speed and prodution rated in rrelation with feed. It is found that the minimum-cost cutting speed increases and the efficient cutting speed range is reduced as machining cost per unit time increases since the cutting speed for maximum production remains almost constant. The machining cost is also lowered and the production rate increases as the feed increases, and the feed should be selected to satisfy the required surface roughness. The machining cost and production rate are hardly affected by the cutting depth if the cutting speed stays below 100m/min, however, they are subject to change at larger cutting depth and the high-efficient speed range also is restricted. It can be established an adaptive optimal cutting conditions can be established in workshop by the auto-selection progam for optimal operation. It is expected that this method for choosing the optimal cutting conditions might contribute to the improvement of the productivity and reduced the cost. It is highly recommended to prepare the optimal cutting conditionthus obtained for future use in the programing of G-function of CNC machines. If proper programs that automatically select the optimal cutting conditions should be developed, it would be helpful to the works being done in the machine shops and would result in noticeable production raise and cost reduction.

• Journal of Mechanical Science and Technology
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• 제17권2호
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• pp.239-245
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• 2003

Ultra precision diamond cutting is a very efficient manufacturing method for optical parts such as HOE, Fresnel lenses, diffraction lenses, and others. During micro cutting, the rake angle is likely to become negative because the tool edge radius is considerably large compared to the sub-micrometer-order depth of cut. Depending on the ratio of the tool edge radius to the depth of cut, different micro-cutting mechanism modes appear. Therefore, the tool edge sharpness is the most important factor which affects the qualities of machined parts. That is why diamond, especially monocrystal diamond which has the sharpest edge among all other materials, is widely used in micro-cutting. The majar issue is regarding the minimum (critical) depth of cut needed to obtain continuous chips during the cutting process. In this paper, the micro machinability near the critical depth of cut is investigated in micro grooving with a diamond tool. The experimental results show the characteristics of micro-cutting in terms of cutting force ratio (Fx/Fy), chip shape, surface roughness, and surface hardening nea. the critical depth of cut.

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.37-41
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• 1990

The quality of cutting surface such as surface roughness, heat affected zone, serf width can be improved by controlling the parameters of cuting process. These parameters includes cutting velocity, laser beam power, material depth and assistant gas. Thermodynamic analysis and systematical experiments are attempted to pedict and determine the optimal cutting condition. There exists the optimal cutting condition to ensure high quality surface. Under this operation, the minimum surface roughness of the mild steel, the stainless steel and the titanium becomes 3.8${\mu}{\textrm}{m}$ 13${\mu}{\textrm}{m}$ and 10${\mu}{\textrm}{m}$ respectively.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.848-851
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• 1996

Based on the minimum cutting time criteria, the tool path generation algorithm of a pocket machining is developed as a form of a built-in cycle for the WOP(workshop oriented programming) of a CNC controller. Based on the given CAD database and tool information, an optimal cutting depth and geometric properties can be generated, then six different tool paths will be generated internally and automatically. Finally, the G code which commands tool movements is generated for CNC machining.

• 한국생산제조학회지
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• 제21권3호
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• pp.382-386
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• 2012

A femtosecond laser with 775nm central wavelength and 150 fs of temporal pulse width was used for multi layered glass cutting applications. Ultrashort pulse was effectively used for clean glass cutting with $50{\mu}m$ depth and minimum cutting width. Laser beam was split to two stages and focused on the top surfaces of each layer. Ablation threshold of used glass was measured to be $2.59J/cm^2$. In experiments, 200mW laser power and 1mm/s scanning speed was used for preliminary experiment. Air gap was the major defect occurring parameter and laser power was less sensitive to glass cutting in the experiment. The maximum cutting speed was measured to be 60mm/min with 2kHz, however, Maximum 3m/min cutting speed can be achievable with a commercially available laser with 100kHz.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.209-214
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• 2002

Mechanical micro-engineering is an easy and cheap way to fabricate micro-structures. If the application of the conventional machining method using flat-end mill becomes available for the micro-manufacturing process, it will be advanced as an extension of the conventional machining process. In this study, micro-grooves cutting using flat-end mill(($\phi$8) was performed. The characteristics on flat-end milling was investigated to improve machinability of micro-grooves. The experiments were performed according to variations of spindle revolution, depth of cut, and feed rate. Machinability through various cutting conditions was evaluated by surface geometry, tool wear, and cutting force. The results show that micro V-grooves of width(pitch) 29${\mu}{\textrm}{m}$ were acquired by flat-end milling. The maximum and minimum roughness of the wall of grooves was 438 and 67nm, respectively

• 한국정밀공학회지
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• 제26권1호
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• pp.43-50
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• 2009

Semi dry cutting known as MQL (Minimum Quantity Lubrication) machining is widely spreaded into the machining shops nowadays. The objective of this research is to suggest how to derive optimum cutting conditions for the milling process in MQL machining. To reach these goals, a bunch of finish milling experiments was carried out while varying cutting speed, feed rate, oil quantity, depth of cut and so on with MQL. Then, response surface analysis was introduced for the variance analysis and the regression model with the experimental data. Finally, desirability function based on regression model was used to obtain optimal cutting parameters and verification experiment was done.

• 산업경영시스템학회지
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• 제45권4호
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• pp.61-69
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• 2022

The function of coolant in machining is to reduce the frictional force in the contact area in between the tool and the material, and to increase the precision by cooling the work-piece and the tool, to make the machining surface uniform, and to extend the tool life. However, cutting oil is harmful to the human body because it uses chlorine-based extreme pressure additives to cause environmental pollutants. In this study, the effect of cutting temperature and surface roughness of titanium alloy for medical purpose (Ti-6Al-7Nb) in eco-friendly ADL slot shape machining was investigated using the response surface analysis method. As the design of the experiment, three levels of cutting speed, feed rate, and depth of cut were designed and the experiment was conducted using the central composite planning method. The regression expressions of cutting temperature and surface roughness were respectively obtained as quadratic functions to obtain the minimum value and optimal cutting conditions. The values from this formula and the experimental values were compared. As a result, this study makes and establishes the basis to prevent environmental pollution caused by the use of coolant and to replace it with ADL (Aerosol Dry Lubricant) machining that uses a very small amount of vegetable oil with high pressure.