• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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• pp.5-14
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• 2002

Hemisphere shapes were machined for different tool paths and machining conditions with ball endmill cutters. It was also found out how feedrate affect the precision of the machining and also tried to study the most suitable feedrate in specific cutting condition. Tool deflection, cutting forces and shape accuracy were measured according to the inclination position of the sculptured surface. As the decreasing of inclination position angle, the tool deflection was increased due to the decreased cutting speed when the cutting edge is approaching toward the center. Tool deflection when upward cutting IS obtained less than that of downward cutting and down-milling in upward cutting showed the least tool deflection for the sculptured surface. For down-milling, the cutting resistance of the side wall direction is larger than that of feed direction. It was found that the tool deflection is getting better as tool path is going to far from the center for convex surface.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.485-491
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• 1999

A burr is formed in every corner of parts as a result of machining, which produces undesirable edge geometry and influence deeply to surface quality of workpiece. Therefore these burrs must be removed certainly. The cost of removing these burrs is directly proportional to their size. Burrs have been among the most troublesome obstruction to high productivity and automation of machining processes. The proper selection of cutting condition and tool geometry will be helpful to reduce the occurrence of burrs. In paper will observe burr formation along helix angle in end milling and certificate experimentally mechanics relation of helix angle and burr formation.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.11
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• pp.977-982
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• 2015

This study uses finite element analysis to evaluate the forming load of tool entrance angle of the cold forward extrusion molding process of helical gear; this can replace the spur gear applied to the Electronic Parking Brake (EPB) system. A cold forging process is often used in the automobile industry as well as in various industrial machines due to its high efficiency. Finite element analysis is frequently used when interpreting results of the forging process. Formality was evaluated by calculating tooth profile filling rate of helical gear. Change in required forming load was investigated when the entrance angle of forward extrusion tool die was changed from $30^{\circ}$ to $60^{\circ}$, also by finite element analysis. We suggest suitable tool entrance angles.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.2
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• pp.25-31
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• 2004

Machinability in metal cutting processes depends on cutting input conditions such as cutting velocity, feed rate, depth of cut, types of work material and tool shape factors. In this study, to assess chip breaking characteristics of a turning process, an equivalent oblique cutting system to this has been established. And the equivalent effective rake angle was determined using side rake angle, back rake angle and side cutting edge angle of the tool. A non-dimensional parameter, Chip breaking index(CB), was used to assess Chip breaking characteristics of chip in conjunction with the equivalent effective rake angle. In case of positive rake angles of the equivalent effective rake, the back rake angle has little effect on the chip breaking characteristics however, in case of negative ones, the side rake angle has some effect on Chip breaking characteristics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1424-1428
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• 2004

A new design for deburring tools for intersecting holes is introduced. The tool tip is mounted on a slender cantilever assembled into a circular shank. The tool tip has been design to cover ranges of exit angle and diameter ratio between intersecting holes. The design is an improvement over the previous ones by the authors. Experiments have been performed on AL6061. With the new design, mild exit burrs with exit angles greater than 45$^{\circ}$ are successfully removed. For large burrs with smaller exit angles, however, the deburring could be incomplete.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.507-512
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• 2000

Due to increasing demand toward improving product quality, various methodologies have been introduced. A brush type grinding tool is one of the most frequently used one to facilitate required process. In order to produce consistent burr shape, various machining conditions have been combined applied to disk grinding process. It has been observed that the burr dimension(shape and width) depends on the inclination angle between grinding disk and workpiece. Drastic increase of tool Wear has been also observed along the inclination angle variation. Various burr shapes have been captured and analyzed using image processing technique.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.1
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• pp.69-76
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• 1997

This paper deals with the machinability based on turning and drilling tests. The main conclusions obtained were as follows. (1) Turning : The roughness of Machined surface decreases with the increase of the rake angle of tools, and the tool wear becomes smaller with the decrease of the rake angle. When the feed rate becomes larger, the fracture of work material in the vicinity of the cutting edge occurs on a larger scale, eventually decreasing tool wear. (2) Drilling : Considering both tool life and productivity, it is reasonable to cut with the high cutting speed and feed rate. The tool wear increases with the increase of feed rate, and the tendency of feed rate on tool wear becomes stronger at the cutting speed $\geq$30m/min.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.71-77
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• 1999

In this study, Cu ferrite was machined with cermet tool to clarify the machinability. The main conclusions obtained were as follows. The tool wear becomes the smallest at the cutting speed of 90m/min with the depth of cut of 0.2mm. The surface roughness becomes larger with increasing the cutting speed and the chamfer angle. The tool with the chamfer angle of $15{\circ}$ shows the best performance. The surface roughness increases almost proportionally with the increase of the chip size. The tool wear decreases with increasing feed in the depth of cut not more than 0.2mm.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.3
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• pp.56-61
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• 2002

CuFe$_2$O$_4$ ferrite was machined with cermet tools to clarify the machinability. The tool wear became the smallest at the cutting speed of 90m/min with the depth of cut of 0.2mm. The surface roughness became larger with increasing the cutting speed and the chamfer angle of tool. The tool with the chamfer angle of 15° showed the smallest wear. The surface roughness increased almost proportionally with the increase of chip size. The tool wear reduced with increasing feed in the depth of cut not more than 0.2mm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.806-809
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• 2000

The factors which can improve tool life in machining are consisted of tool geometries, tool materials, coating methods. cutting environments, cutting conditions and so on. Cutting speed in cutting conditions is one of the important factors which can directly influence on the tool life. This paper deals the machinability which is concerned about the cutting direction and the tilt angle of fret form surface in hot die steel(STD I I). The NC datum were analysrd and the effective tool diameters were calculated according to the change of tilt angle the program which can continue the cutting speed with the change of spindle revolution is developed.