• 한국기계가공학회지
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• 제1권1호
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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.

• 한국기계가공학회지
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• 제15권3호
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• pp.86-92
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• 2016

Mechanical milling, in association with electrical discharge machining (EDM) for hybrid machining, is presented in this paper. An end mill cutting tool, an electrode of the EDM, was used for the system. That means that some parts were cut by the mechanical cutting process and others by the EDM. The possibility of combining both processes was simulated with the cutting simulation software. In addition, the machining reality was verified by measuring the electrical signal from the EDM power supply, which was measured in time and frequency domains. From this initial research, the hybrid machining system proposed in this paper appears to be well suited for difficult to cut material processing.

• 소성∙가공
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• 제19권3호
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• pp.191-196
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• 2010

Tungsten-carbide as typical difficult-to-cut material has excellent mechanical properties such as high thermal resistivity, mechanical strength and chemical durability. However, it is next to impossible for tungsten-carbide to be fabricated the needed parts by cutting process. In this study, for establishing the micro fabrication method of tungsten-carbide for micro injection or compression molding core, the investigation on micro cutting characteristics of tungsten-carbide green part which is made by powder injection molding process and easy to cut relatively was performed. For this, micro endmilling experiments of tungsten-carbide green part were performed according to various cutting conditions. Finally, the wear trend of micro endmill and the appearance of micro rib according to feed-rate and cutting depth per step were analyzed through SEM images of micro cutting feature and microscope images of micro tools.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.947-950
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• 2000

The purpose of this paper is to investigate the effect of the helix angle of endmilling cutter on the cutting characteristics of inconel 718 in up endmilling. To this end cutters with helix angle of $20^\circ$, $30^\circ$, $40^\circ$ and $50^\circ$ degree have been prepared. And a modified cutting force model in up end milling process is presented. Using this cutting force components of 4-tooth endmills with various helix angles have been predicted. Predicted values of cutting force components are well coincide with the measured ones. As helix angle increases overlapping effects of the active cutting edges increase.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.930-933
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• 2000

Experimental study was conducted for finding the characteristics of machining precision according to the change of feedrate when ball endmilling of semisphere shape. The values of tool deflection and cutting force were measured simultaneously by the systems of eddy-current sensor and dynamometer. The machining precision was analyzed by roundness values, which were deeply relating with tool deflection and forces. the roundness was decreased in down-milling than in up-milling for each feedrate. As the cutting edge is moved to radius direction on the tool path, the tool deflection and the cutting force were seemed to be decreased. As the tool path was moved downward, the values of roundness, cutting force and tool deflection were obtained better ones. When compared the values of roundness, cutting force and tool deflection for different feedrate, the best machining accuracy was obtained at feed rate of 90mm/min in down-milling.

• International Journal of Precision Engineering and Manufacturing
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• 제1권2호
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• pp.67-75
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• 2000

virtual computer numerical control(VCNC) arises from the concept that one can experience pseudo-real machining with a computer-numerically-controlled(CNC) machine before actually cutting an object. To achieve accurate VCNC, it is important to determine abnormal behavior, such as chatter, before cutting. Detecting chatter requires an understanding of the dynamic cutting force model. In general, the cutting process is a closed loop system the consists of structural and cutting dynamic. Machining instability, namely chatter, results from the interaction between these two dynamics. Several previous reports have predicted stability for a single path, using a simple cutting force model without run out and penetration effects. This study considers both tool run out and penetration effects, using experimental modal analysis, to obtain predictions that are more accurate. The machining stability during a corner cut, which is a typical transient cut, was assessed from an evaluation of the cutting configurations at the corner.

• 한국정밀공학회지
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• 제18권3호
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• pp.195-204
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• 2001

Virtual computer numerical control(VCNC) arises from the concept that one can experience pseudo-real machining with a computer-numerically-controlled(CNC) machine before actually cutting an object. To achieve accurate VCNC, it is important to determine abnormal behavior, such as chatter, before cutting. Detecting chatter requires an understanding of the dynamic cutting force model. In general, the cutting process is a closed loop system that consists of structural and cutting dynamics. Machining instability, namely chatter, results from the interaction between these two dynamics. Several previous reports have predicted stability for a single path, using a simple cutting force model without tool runout and penetration effects. This study considers both tool runout and penetration effects, using experimental modal analysis, to obtain more accurate predictions. The machining stability in the corner cut, which is a typical transient cut, was assessed from an evaluation of the cutting configurations at the corner.

• 소성∙가공
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• 제19권2호
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• pp.107-112
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• 2010

A multi-stage gear mold including gears of 2mm and 1.5mm diameter was designed and machined in this research for developing micro gear mold manufacturing technology with micro endmill. Mechanical shapes having differential micro teeth were analyzed to be formed as designed and processing conditions were optimized by analyzing machined surface chip and cutting force. Based on the results, a prototype of micro multi-stage gear mold was manufactured.

• 한국정밀공학회지
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• 제12권3호
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• pp.119-129
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• 1995

In this paper, the inclined endmilling process with a 3-axis machining center using inclined jigs is introduced for the purpose of reducing overall Dies/Molds machining time and improving the machining accuracies. In order to analyze the cutting mechanism of a given endmill more accurately, the unification of the cutting mechanism model of 3-different- kind endmills is carried out by using a nose radius as a parameter. By adding radial runouts as a parameter which influences on surface roughness, the superposition method which defines the effective cusp height superposing the cutter mark height and the conventional cusp height is advanced. And 3-D suface topography predicted in this paper looks like the surface normally observed in practice. Through machining experiments, the adequacy of the superposition method was confirmed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.437-438
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• 2008