• Journal of the Korean Society for Precision Engineering
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• v.25 no.6
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• pp.40-46
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• 2008

Ultraprecision cutting of steels with geometrically defined single crystal diamond tools is handicapped by excessive tool wear. This paper presents a new approach to suppress the wear of single crystal diamond tool in cutting of steels. In general, it is said that the wear of diamond tool is caused by chemically reactive wear under high temperature and high pressure conditions. In order to suppress such chemical reactions, the time of contact between the diamond tool and the steel work in cutting was controlled by employing the intermittent cutting method such as fly-cutting. Series of intermittent cutting experiments have been carried out to control the tool-work contact time by changing one cycle of cutting length and cutting speed. The experimental results were shown that the tool wear was much dependent on the contact time regardless of the cutting speed, and that the wear was much suppressed by reducing the tool-work contact time. It is expected that the steels can be successfully cut with a single crystal diamond tool by controlling the contact time.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.2
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• pp.102-111
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• 1997

This paper deals with the machinability based on turning of WC-Co allows with the coated and the sintered diamond tools. The main conclusions obtained are as follows. (1) When machining WC-10%Co alloy, the flank wear of sintered diamond tool increases more largely with the increase of cutting speed in comparison with coated diamond tool. The tool wear decreases with the increase of the grain size and nose radius of sintered diamond tool. (2) When machining WC-20%Co alloy, the tool wear and cutting force decrease with the decrease of rake angle. Their exists a certain cutting speed range to exhibit the smallest tool wear in machining the WC-20%Co alloy, and this critical cutting speed becomes higher by 2 times in the case of coated diamond tool compared with sintered diamond tool. (3) The machinability becomes better with the increase of Co content. The effects of cutting speed and feed rate on the roughness of machined surface become smaller with the increase of Co content.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.951-954
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• 2000

This paper presents a new cutting method, i.e. diamond cutting, aided by electrolysis, in order to cut ferrous materials with diamond tools. Diamond cutting is widely applied in manufacturing ultraprecision parts such as magnetic disk, polygon mirror, spherical/non-spherical mirror and copier drum, etc. because of the diamond tool edge sharpness. In general, however, diamond cutting cannot be applied to cutting steels, because diamond tools wear excessively in cutting iron based materials like steel due to their high chemical interaction with iron in high temperature. In order to suppress the diffusion of carbon from the diamond tool and to reduce increase of cutting force due to size effect, we attempt to change chemically the compositions of iron based materials using electrolysis in a limited part which will be soon cut. Through experiments under several micro-machining and electrolysis conditions, cutting using electrolysis, compared to conventional cutting, was found to result in a great decrease of the cutting force, a better surface and much less wear tool.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.502-506
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• 2001

This paper presents a new method for cutting steel with a diamond tool using electrolysis. The electrolysis is adopted in the diamond cutting to prevent the high chemical activity between a diamond tool and an iron-based workpiece. The basic principle of the method is to oxdize a thin substrate of the workpiece by electrolysis ahead of the diamond tool which cuts the oxidized layer. A desired shape can be obtained by repeating this process. The cutting force is reduced because the diamond tool removes only the weakened material by electroysis. The reduction of the cutting force suppresses the excessive wear of the diamond tool. The oxidization penetrates several micrometers in depth along the previously formed shape. The corrosion rates depend on current density and make suggestions on the optimum cutting conditions.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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• pp.122-130
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• 1996

In this study, machinability of some aluminum-magnesium alloy are experimentally investigated using polycrystalline diamond tool with turning, and evaluated some independent cutting variables affected micrometal cutting characteristics as cutting force, specific cutting resistance, shear angles. To know the effect of cutting parameters of single point diamond machining, experiments were performed to measure cutting forces for high speed turning of aluminum alloy 6061-T6, SM45C and FC20 with poly- crystalline diamond and coated cemented carbide tool. Independent cutting variables were changed to a variety of cutting speed, feed rate, rake angles, material properties of workpiece and tool. Futhermore. Some useful informations are obtained in this study can guide micro metal cutting of aluminum alloy with diamond tool.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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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.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.5
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• pp.127-133
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• 1998

This research intends to gain the sight for the qualitative characteristics of precision cutting by using the CNC lathe with a mono-crystal diamond(MCD) and a poly-crystal diamond(PCD) tool on the cutting distance. In case of an MCD tool, as the cutting distance increases, the surface roughness becomes worse and the standard deviation of surface roughness is small. In case of a PCD tool, as the cutting distance increases, the surface roughness becomes stable with a large standard deviation. The cutting force ratio(Ft/Fn) decreases as the nose radius increases and the decreasing ratio becomes larger for small nose radius.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.78-83
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• 1996

This paper presents the characteristics of surface roughness and cutting force in ultraprecision cutting of aluminium alloy using natural diamond tools whose edge radii are smaller than those of tools made of other materials. The feed rate and depth of engagement were set to be a micrometer order. After measuring the surface roughness of machined surface and cutting force for each cutting condition, the relations between the surface quality and its condition were investigated qualitatively. If the feed rate was under a certain limit, the machined surface quality was deteriorated unexpectedly. This is supposed to have happened due to vibration leading its condition to abnormal one. In a certain situation the machined surface roughness by a natural diamond tool was inferior to that made by a carbide tool whose cutting edge radius is larger. This is supposed to be caused by not normal machining but burnishing effect.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.41-46
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• 1996

In this study, unsintered and pre-sintered low purity alumina ceramics were machined with various tools to clarify the machinability, optimum tool materials and optimum cutting conditions. The main conclusions obtained were as follows. (1)In the case of dry cutting, the sintered diamond and natural diamond tools exhibit better performance in machining of the ceramic pre-sintered at lower temperature, and the tool lives of both tools in machining the ceramics pre-sintered at high temperature becomes extremely short. (2)The performance of CBN tool becomes better in dry machining of the ceramics pre-sintered at higher temperature. (3)When the pre-sintered ceramics were wet machined with sintered diamond, the tool life becomes considerably long, and higher cutting speed can be used than in the case of the CBN and ceramic tools, the tool lives becomes shorter at wet cutting than at dry cutting, especially exhibiting extremely short tool life in wet cutting with ceramic tool.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.2 s.191
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• pp.33-40
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• 2007

In this study, presintered and full sintered low purity alumina ceramics were machined with various tools to clarify the effect of cutting fluid in machinability. The main conclusions obtained were as follows. When the presintered ceramics were wet machined with sintered diamond tool, the tool wear becomes extremely large, and higher cutting speed can be used than in the case of full sintered ceramics. The productivity of wet cutting with the sintered diamond tool is much higher than that of dry cutting. In the case of the CBN and ceramic tools, the tool wear were smaller at wet cutting than at dry cutting, especially exhibiting considerably larger grooved tool wear in wet cutting with ceramic tool.