• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.344-349
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• 2005

This paper is studied on the effect of TiAlN coated ball end mill on cutting characteristic of high hardness steels in dry cutting condition without coolant. KP4 steels[HRC32] and STD11[HRC60] heat treated steels wert: used as the workpiece and WC-Co ball end mill and single and multi layer TiAlN coated ball end mill were utilized. Results showed that TiAlN coated ball end mill were increased the cutting length than WC-Co ball end mill in the cutting speed$[245\~320m/min]$ about $2\~5$ times for KP4 steels and about $2.7\~4.3$ times for STD11 heat treated steels. The multi layer TiAlN coated ball end mill is good about $1.2\~1.7$ times for KP4 steels and STD11 steels than single layer coated.

• 한국기계가공학회지
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• 제9권1호
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• pp.81-86
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• 2010

This paper investigated into process characteristics of AlTiN coated layers for machining to the direction of upper and lower in plastic mold material (KP-4) with the cemented carbide ball endmill with the diameter of 8mm coated AlTiN layers (1~4) step by step using machining center. The material used in experiments was KP-4 that was machined by three types of inclined angles; $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ As estimated mechanical properties of AlTiN coated layers, it was shown the most result in the condition of three layered coating that the coating that the coating depth, the hardness of the coated layer and the surface roughness of the coated layer were $13{\mu}m$, Hv 3027.3 and $0.042{\mu}m$, respectively. The cutting component was better at the condition of upper direction than that of lower direction in all experimental conditions and indicated to be less which the bigger angle of the material was increased the effective diameter of the tool.

• 한국생산제조학회지
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• 제18권6호
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• pp.629-635
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• 2009

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 $\Phi$ 8mm 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, and surface roughness were studied. The cutting component force showed a good agreement better the up ward direction than the down ward direction under all experimental conditions. In case of the condition per the material shape, it was lessen when the tool have larger angle because the average effective diameter of the tool is larger. The surface roughness showed good condition in case of the up ward than the down ward direction. And, in the 3rd layer of AlTiN coating, it showed the most suitable condition.

• 한국정밀공학회지
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• 제21권7호
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• pp.62-69
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• 2004

This paper presents an experimental study on the dimensional error in ball-end milling. In the 3D free-formed surface machining using ball-end milling, while machining conditions are varied due to the Z component of the feed and existing hemisphere part of the ball-end mill, the mechanics of ball-end milling are complicated. In the finishing, most of cutting is performed the ball part of the cutter and the machined surface are required the high quality. But the dimensional errors in the ball-end milling are inevitably caused by tool deflection, tool wear, thermal effect and machine tool errors and so on. Among these factors, the most significant one of dimensional error is usually known as tool deflection. Tool deflection is related to the instantaneous horizontal cutting force and varied the finishing cutting path. It lead to decrease cutting area, thus resulting cutting forces but the dimensional precision surface could not be obtained. So the machining experiments are conducted fur dimensional error investigation and these results may be used for decrease dimensional errors in practice.

• Design & Manufacturing
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• 제17권1호
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• pp.33-39
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• 2023

The ball end mill is a type of cutting tool that is widely used to process complex mold shapes including aspheric surfaces. Unlike the flat end mill in which the cutting edge is formed on the cylindrical handle, the cutting edge is formed from the cylindrical handle to the hemispherical shape, which is advantageous for processing curved shapes. However, since the cutting speed continuously changes during machining due to the helix angle of the cutting edge or the machining inclination angle, it is difficult to obtain a precise machined surface. Therefore, in this paper, machining was performed while changing the helix angle of the ball end mill and the angle of the machining slope under the same cutting conditions for STD 11 material, which is widely used as a mold material. Through this, the effect of the two variables on the roughness of the machined surface was analyzed. As a result, if the helix angle was 0 degrees, it showed the best surface roughness of Ra. 0.16 ㎛. When the helix angle was 20 degrees, the best surface roughness of Ra. 0.18 ㎛ was occurred.

• Design & Manufacturing
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• 제16권4호
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• pp.17-23
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• 2022

Recently, several studies are being conducted to achieve a curvature of 180° or more for the edge of the display glass. The thermocompression molding process is applied to the manufacture of curved glass, and high hardness G5 graphite is used as the mold material to withstand the impact applied to the mold. G5 graphite has high hardness and strong brittleness, which makes tool wear and surface damage easy during machining. Therefore, the demand for diamond-coated tools with good mechanical properties is increasing in the G5 machining field. In this study, the optimal cutting conditions and machinability of a nanodiamond (NCD) coated ball end mill being developed by a tool manufacturer were analyzed and evaluated. For this purpose, the same test was performed on the microdiamond (MCD) coated ball end mill and compared together. In summary, the machinability of MCD and NCD coated tools showed better cutting performance at a cutting speed of 282 m/min, a feed rate of 1,400 mm/min, and a radial depth of cut of 0.08 to 0.1 mm.

• 청정기술
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• 제12권3호
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• pp.182-189
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• 2006

본 연구에서는 생산성 향상을 위하여 적용 분야가 점차로 확대되고 있는 고속 절삭가공의 경제성 및 환경비용을 평가하였다. 가공시간 및 가공비용이라는 절삭공정의 경제성 평가 모델과 더불어 수학적으로 모델링 된 절삭유제의 손실량 및 폐 유제 처리비용을 이용하여 환경비용을 고려한 절삭공정의 생산비용을 분석하였다. 분석에는 CBN 볼 엔드밀을 사용한 고속가공과 여러가지 냉각방식을 적용한 고속 선삭가공 공종에 대한 공수수명 및 공구마모 실험 데이터를 이용하였다. 고속 밀링가공에서 절삭속도가 높을수록 생산비용은 작아져서 고속가공의 장점을 그래도 보여주었다. 압축공기, 냉풍, 수용성 절삭유제, 건식 절삭의 네 가지 냉각방법을 사용한 선삭가공의 분석에서는 절삭유제를 이용한 냉각방식이 절삭유제를 사용하지 않은 방식에 비하여 공수수명의 향상으로 생산비용이 작았으나 환경비용을 고려하면 냉풍을 이용한 냉각방식이 생산성과 환경영향의 모든 면에서 가장 우수하였다.