• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.71-76
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• 2008

Micro end-milling is one of effective technology that is able to do ultra-precision machining while increasing the productivity and has wide application field. But selection of machining condition is very difficult because of complicated machining mechanism. Therefore this study was carried out to select working factors to get the optimum surface roughness. Machining condition are depth of cut, feed rate and spindle revolution. The result of this study showed that Surface roughness was affected, in the other of depth of cut, spindle revolution, feed rate. And this study provided an regression equation relating surface roughness to working factors through Regression Analysis and determination coefficient of regression equation had a satisfactory reliability of 79%.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.91-98
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• 2014

The purpose of this research is to investigate optimum machining conditions to improve the quality of die using the CAD/CAM system(Power Shape/Power Mill) and 3D printing. Surface roughness is widely used as an index for processing degree of accuracy. The Power Shape was used to model the shape of product. And the model shape is confirmed by 3D printing system(BFB-3000). Also, tool path and NC-codes were generated using Power Mill. Finally, the product was cut using CNC machine(NBS-2025). The cutting time and surface roughness were measured by measuring instrument. And then this process was repeated by changing the conditions to find optimal machining conditions. The surface roughness behavior with regard to specific factors were analyzed. Through this study, the optimal machining condition can be obtained.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.3
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• pp.99-103
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• 1998

The curved surface machined by plate end mill causes a excess non-cutting volume, in these cases ball end mill is used for the curved surfaces. This study is aimed to obtain the optimum cutting conditions of various cutting speed, table speed, tool diameter, radius of curvature roughness on the conditions of various cutting speed, tool diameter, radius of curvature when machining the curved surface using the ball end mill. After designing curve rates, obtaining NC data by CAD/CAM system through CC-Cartesian method and transferred the data through DNC system, we machined the specimens by the CNC machining center, The surface roughness of specimens was measured by surface roughness tester and CNC 3D coordinate measuring machine. The cutting condition were the same as follow velocity; 15, 20, 25 30m/min, feed rate;40, 60, 80, 100m/min and radius of curvature; 30,40,50,60mm, tool diameters; ø8, ø12, ø16, ø 20mm. Analizing the working results, we can acquire the optimum cutting condition of curved specimen at the cutting velocity of 20~25m/min and the feed rate of 80mm/min. As the same cutting condition the best surface roughness was showed at ø16mm of the tool diameter. But the tool diameter was smaller than ø8mm. we could improve for the surface roughness by controlling the cusp.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.33-38
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• 1995

In this study, unsistered, pre-sintered and sintered low purity alumina ceramics were machined with various tools to clarify the machniability, the optimum tool materials and the optimum tool materials and the optimum cutting conditions. The maon conclusions obtained were as follows. (1) Machined withalloy steel tool, the machinabilty of te pre-sintered ceramics becomes better with the decrease of pre-sintering temperature, but that of unsintered ceramics(white body) was extremely poor. (2) In the case of carbide tool K01, the tool life in machining white body was the longest, and the machinabilty of pre-sintered ceramics becomes poorer with the increase of the pre-sintering temperature. (3) In the case of ceramic tool, the 10000-1100 .deg. C pre-sintered ceramics showed te best machinability within a certain cutting speed range. So far as dry machining, the above combination and conditions showed the highest productivity. (4) When the pre-sintered ceramics were wet machined withsintered diamond tool, the tool life becomes extremelylong, and higher cutting speed can be can be used than in the case offull-sintered ceramics. The productivity of wet cutting is much higher than that ofdry cutting.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.698-701
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• 2005

We have investigated experimentally a nano patterning using electron beam lithography for the nickel stamper fabrication. Recently, DVD and Blu-ray disk(BD) have nano-scale patterns in order to increase the storage density. Specially, BD has 100nm-scale patterns which are generally fabricated by electron beam lithography. In this paper, we found optimum condition of electron-beam lithography for 100nm-scale patterning. We controlled various conditions of EHP(acceleration voltage), beam current, dose and aperture size in order to obtain optimum conditions. We used 100nm-thick PMMA layer on a silicon wafer as photoresist. We found that EHP was the most dominant factor in electron-beam lithography.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.288-294
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• 2001

Present CAM technology cannot provide important physical property such as cutting farce and machined surface. Thus, the selection of cutting conditions still depends on the experience of an expert or on the machining data handbook in spite of the developed CAM technology. This paper presents an advanced methodology to help the worker to determine optimum cutting condition for CHC machining that excludes the need for expertise of machining data handbook. The virtual machining system presented in this paper can simulate the real machining states such as cutting farce and machined surface error. And virtual machining system can schedule feed rate to adjust the cutting force to the reference force.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.19-24
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• 2003

Recently, various efforts to make more speedy and precision machine tool to improve productivity and also various efforts to solve environmental problem are going on, so that dry cutting in manufacturing industry, which needs environmental conscious design and development of manufacturing technique, is becoming a very important assignment to solve. Because dry cutting does not use cutting fluid, we need other methods that can be used instead of cutting fluid, which does cooling, lubricating, chip washing, and anti-corrosion. Especially, because turning is a continuous work, the consideration of tool life and surface roughness due to continuous heat and poor lubrication is important. The purposes of this paper are the consideration of how well the compressed air can work instead of cutting fluid, and also the development of the method to select the optimum machining condition by the minimum numbers of experiments through the Taguchi method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.4
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• pp.27-32
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• 2006

This study aims to find the optimal cutting conditions, when are nonferrous metals(aluminum and silicon) are machined with diamond tool of diamond turning machine. Diamond turning machine has been widely used in manufacturing optical reflectors of nonferrous metals. Such as aluminium and copper are easy to be machined because of their proper ductility. But optical crystals being discussed here are characterized by their high brittleness which makes it difficult to obtain high quality optical surfaces on them. The purpose of this study is to find the optimum machining conditions for ductile cutting of silicon and aluminium.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.5
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• pp.42-55
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• 1994

Presently, abrasive processing is on eof several methods for cutting and grinding brittle materials, and high quality in dimensional accuracy and surface roughness are often required as a structural components, therefore most of them has to be ground. In manufacturing of tungsten-carbide components, grinding by diamond wheel is usually adopted in order to provide configurational and dimensional accuracy to the components. The present study proposes the experi- mental research of optimum condition to the high quality surface grinding of the WC-Co material using diamond abrasive wheel in order to minimize the damage on the ground surface and to pursue the precise dimension by conventional grinding machine. Brief investigation is carried out to decrease the dressing is constant, theoretical grinding effect such as machining precision is changed according to the speed of workpiece. Accordingly, normal and tangential grinding forces, which are Fn, Ft were analyzed for the machining processes of WC-Co material to obtain optimum grinding conditions, 3-point bending test is carried out to check machining damage on the ground surface layer, which is one of sintered brittle materials.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.8-13
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• 1997

In order to utilize the information of well-known grinding data or grinding machine, a database needs to be designed by considering the delicate property of the machine tools for the high precision and quality of the demanding specification. Among the machine tools, machining conditions of the grinding are various and knowledge repeatance obtained form the grinding process are less credable.Therefore it is desirable for D/B, which is used to set the grinding conditions, to utilize the maximum machine tool capability. The present paper studied occurance limit of chatter vibration and burn considering the characteristics of machine tool. And also basic experiments were performed to establish optimum grinding canditions which can maximize the machining efficiency.