• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.190-195
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• 2003

CFRP composite has a lot of merits such as mechanical characteristic, light weight, and thermal resistance. For these merits CFRP is applied to so many industrial area. In this paper, the relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48 plies specimen with the $\phi$8, $\phi$10, $\phi$12mm cemented carbide drill. The results are analyzed with consideration of cutting force, stack thickness and drill diameter.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.54-61
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• 2010

In this research KP-4, one of the plastic mold steels, was coated with the AlTiN from one layer to four layers by the PVD method in the $\Phi$ cemented carbide ball end mill. Coated KP-4 was processed with various conditions. For example, slope of $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ the spindle rotation speed was changed from 10,000rpm to 16,000rpm, the tool feeding speed was changed from 1,300mm/min to 1,700mm/min, the depth of cut was also changed from 0.3mm to 0.9mm, and etc. Cutting component force according to the coating layer number, surface roughness, and the wear of tool were studied.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.03a
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• pp.152-157
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• 1995

In Turning It is good selection of cutting condition and cutting tools that influence upon the accuracy of dimension manufacturing efficiency and extension of tool life. Among them especially the identification of cutting force due to the change of cutting conditions which exerts a great influence on the turning is very important. In this study the cutting resistance due to the change of cutting conditions was caculated by using the energy method and good agreement in shown between theoritical and experimental results which were tested for the cutting resistance at the cemented carbide cutting tools with workpieces of SM20C and SM 45C.

• Journal of Powder Materials
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• v.14 no.5
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• pp.315-319
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• 2007

Pure WC or WC with low Co concentration less than 0.5 wt.% is studied to fabricate high density WC/Co cemented carbide using vacuum sintering and post HIP process. Considering the high melting point of WC, it is difficult to consolidate it without the use of Co as binder. In this study, the effect of lower Co addition on the microstructure and mechanical properties evolution of WC/CO was investigated. By HIP process after vacuum sintering, hardness and density was sharply increased. The hardness values was $2,800kgf/mm^2$ using binderless WC.

• Restorative Dentistry and Endodontics
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• v.2 no.1
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• pp.7-9
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• 1976

This study was performed to reveal the effect of self-curing acrylic resin to dental pulp when the resin was used directly on the freshly cut dentin. Class V cavity preparations were made on the teeth of dogs with No. 701 carbide bur at a speed of 200,000 rpm and with an air water spray. Petrolatum jelly was coated on the inner surfaces of the cavities. After that, doughs of self-curing acrylic resin were filled in these cavities and before completely set these were removed and cemented with zinc oxide and eugenol cement. The dogs were sacrified between 1 day and 3 weeks at the intervals of one week and routinely processed with hematoxylin and eosin stain for histopathologic interpretation. The results were as followings; 1. The inflammatory changes of the pulp can be seen after the use of self-curing acrylic resin on freshly cut dentin. 2. The inflammatory changes of the pulp were not completely subsided until the end of third experimental week.

• The Journal of Korean Academy of Prosthodontics
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• v.13 no.1
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• pp.23-26
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• 1975

The purpose of this study was to measure the retentive force of various kinds of dental cement. Cross-cutting the half of the occlusal surface, pinholes were prepared on the dentin with No. 557 carbide bur. No. 557 steel burs were cemented in the pinholes and retentive force was measured by removing the burs with Instron testing machine. The Instron testing machine was operated at a rate of 0.2 cm per minute. The following results were obtained : 1. The retentive force of zinc phosphate cement(A), reinforced zinc oxide and eugenol cement and polycarboxylate cement were similar to each other, but that of zinc phosphate cement (A) was the highest of all. 2. The retentive force of zinc phosphate cement (B) was the lowest of all.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.5
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• pp.1-6
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• 2010

The wavelet transform is a popular tool for studying intermittent and localized phenomena in signals. In this study the wavelet transform of cutting force signals was conducted for the detection of a tool failure in turning process. We used the Daubechies wavelet analyzing function to detect a sudden change in cutting signal level. A preliminary stepped workpiece which had intentionally a hard condition was cut by the inserted cermet tool and a tool dynamometer obtained cutting force signals. From the results of the wavelet transform, the obtained signals were divided into approximation terms and detailed terms. At tool failure, the approximation signals were suddenly increased and the detailed signals were extremely oscillated just before tool failure.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.168-173
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• 2005

Composite material is combined with two or more chemical ingredient and different components. FRP has been widely used for the structure of aircraft, ships, automobiles, sporting goods and other machines because of their high specific strength, high specific stiffness and excellent fatigue strength. Recently, the development of machine tool and cutting tool greatly relies on high speed process to satisfy high precision, high efficient machining, shortened process time to maximize material removal rate (MRR) through high cutting speed and feed speed. The research molded CFRP, GFRP as stacking sequence methods of two direction (orientation angle $0^{\circ}\;and\;0^{\circ}/9^{\circ}$) hand lay-up, drilled molded plates using cemented carbide drill and examined chip shapes, surface roughness properties.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.398-401
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• 1999

We prepared diamond thin films on WC-Co substrate in a mixtured $H_2-CH_4-O_2$, gas, using 13.%MHz RF PACVD. Scanning electron microscopy, X-ray diffraction and Rarnan spectroscopy were used to analyze the characteristics of thin film, and tribometer of ball-on-disk type were used to test the wear resistance between thin film and substrate. The good diamond quality and wear resistance was appeared with cemented tungsten carbide substrate treated with oxygen plasma.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.191-192
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• 2006

The deformation under radial pressure of rectangular dies for metal powder compaction has been investigated by FEM. The explored variables have been: aspect ratio of die profile, ratio between diagonal of the profile and die height, insert and ring thickness, radius at die corners, interference, different insert materials, i. e. conventional HSS, HSS from powders, cemented carbide (10% Co). The analyses have ascertained the unwanted appearance of tensile normal stress on brittle materials, also "at rest", and even some dramatic changes of stress patterns as the die height increases with respect to the rectangular profile dimensions. Different materials behave differently, mainly due to difference of thermal expansion coefficients. Profile changes occur when the dies are heated up to the temperature required for warm compaction. The deformation patterns depend on compaction temperature and thermal expansion coefficients.