• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.426-429
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• 2005

In this study, the formed tool is used to machine of bearing raceway and a shape compensation scheme is proposed to compensate for shape of it in turning process. It is introduced the conventional design method of the formed tool; a simple depth compensation method and a drawing compensation method. And it is performed to investigate in detail properties of the formed tool about a tool angle and problems of a turning process of bearing raceway using the formed tool. The applicability of the proposed scheme is examined by comparing the experimental results obtained by a new designed formed tool with those obtained by a conventional tool.

• International Journal of Precision Engineering and Manufacturing
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• v.1 no.1
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• pp.15-21
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• 2000

This study presents a procedure for analyzing chip-tool friction and shear processes in 3-D cutting with a single point tool. The edge of a single point tool including a circular nose is modified to an equivalent straight edge, thereby reducing the 3-D cutting with a single point tool to the equivalent of oblique cutting. Then, by transforming the conventional coordinate systems and using the measurements of three cutting force components, the force components on the rake face and shear plane of the equivalent oblique cutting system can be obtained. As a result, the chip-tool friction and shear characteristics of 3-D cutting with a single point tool can be assessed.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.6
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• pp.190-196
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• 1999

In this study, a procedure for analyzing chip-tool friction and shear processes in 3-D cutting with a single point tool has been established. The edge of a single point tool including circular nose is modified to the equivalent straight edge, then 3-D cutting with a single point tool is reduced to equivalent oblique cutting. Transforming the conventional coordinate systems and using the measured three component of cutting forces, force components on the rake face and the shear plane of the equivalent oblique cutting system can be obtained. And it can be possible to assess the chip-tool friction and shear characteristics in 3-D cutting with a single point tool.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.139-145
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• 1996

Tapping is one of the most widely used machining operations. There are several methodes of producing external screw threads, e.g. turning, milling with single or multiple cutter, rolling, and grinding, but the methods available for cutting enternal threads are less numerous, and for threads in small holes, tapping is employed almost exclusively. In this study, the tap with the various geometry has been developed in order to tap special workmaterial at considerably higher cutting speed than that of the conventional HSS tap. The experimental tests are run with various cutting speed by using a piezo type tool dynamometer to measure tapping torque. Tapping torque is affected by the design of the tap, which seems to be due to internal friction and shearing of the metal. It is clarified that the process of chip formation strongly depends on rake angle, relief angle, angle of twist.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.34-40
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• 1998

The burr produced on piece part edges in machining operations must be removed for most parts to function effectively. Although considerable cost have been expended in improving deburring methods, little energy has been applied toward minimizing burrs. This study has been carried out to prevent the burrs produced on pure aluminium under various working condition and specimen shape in turning operations. The computer image processing system was used for measurement of size of burr, such as burr length, burr depth and burr area. The size of burr showed a decreasing tendency with the increase of rake angle and side cutting angle but it increased rapidly with the increase of depth of cut and the cutting speed has no effect on size of burrs. The size of burr rapidly decreased with the increase of edge angle and burrs are not occurred if edge angle is over 80$^{\circ}$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.122-125
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• 1993

The various geometry of tap been developed in order to tap special workmaterial at considerably higher cutting speed than that of the conventional HSS tap. In this paper a piezo type tool dynamomerer is constructed and used to measure the torque. The experimental tests are run with various cutting speed. It is clarified that the process of chip formation strongly depends on rake angle, relief angel, angel of twist.

• The KSFM Journal of Fluid Machinery
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• v.8 no.2 s.29
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• pp.16-22
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• 2005

This research inspects the discharge state for inside of sedimentation basin, and, through the aboard literature and data, examine sedimentation sludge about discharge plan of effective sedimentation sludge that can discharge in state of high concentration. In this study, we are going to attempt an economy with improvement efficiency for discharge of sedimentation sludge in a water treatment plant.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.259-264
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• 2003

This research inspects discharge state of inside of sedimentation basin, md, through the aboard literature and data, examine sedimentation sludge about discharge plan of effective sedimentation sludge that can discharge in state of high concentration.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.4
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• pp.91-98
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• 2000

In this paper , presented is a method of on-line estimation of the radial immersion ratio and cutting force ratio using cutting force. When a tooth finishes sweeping, sudden drop of cutting forces occurs. These force drops are equal to the cutting forces that act on a single tooth at the swept angle of cut and can be obtained from cutting force signals in feed and crossfeed directions. The ratio of cutting forces in feed and cross-feed directions acting on the single tooth at the swept angle of cut is a function of the swept angle of cut and the ratio of radial to tangential cutting force. In the research, it is found that the ratio of radial to tangential cutting force is not affected by cutting conditions and axial rake angle. Therefore, the ratio of radial to tangential cutting force determined by just one preliminary experiment can be used regardless of the cutting conditions. Using the measured cutting forces, the radial immersion ratio is estimated along with the cutting force ratio at that immersion angle. Various experiments show that the radial immersion ratio and instantaneous ratio of the radial to tangential direction cutting force can be estimated by the proposed method very well.

• Geomechanics and Engineering
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• v.31 no.3
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• pp.249-263
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• 2022

The specially-shaped Polycrystalline Diamond Compact (PDC) cutter is widely used in drill bit design due to its advantages of high rock cutting efficiency, strong impact resistance and long service life in hard and abrasive formation drilling. A detailed understanding of rock cutting behavior of worn specially-shaped PDC cutter is essential to improve the drilling efficiency and decrease the drilling costs. In this paper, the theoretical models of two new principles (loading performance (LP) and cutting performance (CP)) are derived for evaluating the cutting process of worn specially-shaped cutter, the theoretical models consider the factors, such as cutter geometry, aggressiveness, stress state, working life, and rock cutting efficiency. Besides, the numerical model of heterogeneous granite is developed using finite element method combined with Voronoi tessellation, the LP and CP of 12 kinds of worn specially-shaped PDC (SPDC) cutters are analyzed. The results found that the mechanical specific energy (MSE) of worn cutters first increase and then decrease with increasing the cutting depth, and the MSE increase with the increase of back rake angle except for Conical cutter and Wedge-shaped cutter. From the perspective of CP, the worn PDC cutters are more suitable for the smaller cutting depths, and the back rake angle has little effect on the CP of the specially-shaped worn PDC cutters. Conical cutter, Saddle-shaped cutter and Ellipse-shaped cutter have the highest CP value, while Rhombus-shaped cutter, Convex cutter and Wedge-shaped cutter have the lowest value in selecting cutters. This research leads to an enhanced understanding of rock-breaking mechanisms of worn SPDC cutters, and provides the basis to select of specially-shaped PDC cutters for the specific target formation.