• 한국정밀공학회지
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• 제23권12호
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• pp.30-37
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• 2006

In this work, the surface integrity smoothened with a ball end mill was investigated. Because surface integrity mainly affects the manual finishing process, $RV_{AM}$(Remaining Volume After Machining) was introduced, and it gives the relation between machining process and finishing process. Runout and phase shift which adversely affect surface integrity were considered in the generation of surface topography. Cutting points in ball end milling were identified with positional vectors and a set of vectors which have the minimum height in unit area was selected for the generation of surface and $RV_{AM}$. $RV_{AM}$ variation according to runout and phase shift was calculated and experimentally verified in proposed HSM conditions for mold machining. From the simulations and the experiments, a desirable High Speed Machining condition was suggested.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 Handout for 2000 Inter. Machine Tool Technical Seminar
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• pp.19-27
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• 2000

High speed machining (HSM), specifically end milling and ball end cutting, is attracting interest in the die/mold or aerospace industries for the machining of complex 3D surfaces. HSM of difficult-to-cut materials such as die/mold steels, titanium alloys or nickel based superalloys generates the concentrated thermal/frictional damage at the cutting edge of the tool and rapidly decreases the tool life. Following a brief introduction on HSM and reated aerospace or die/mold work, the paper reviews published data on the effect of cutter/workpiece orientation and cutting environments on tool performance. First, experimental work is detailed on the effect of cutter orientation on tool life, cutting forces, chip formation, specific force and workpiece surface roughness. Cutting was performed using 8 mm diameter PVD coated solid carbide cutters with the workpiece mounted at an angle of 45 degree from the cutter axis. A horizontal downwards cutting orientation proveded the best tool life with cut lengths ∼50% longer than for all other directions (horizontal upwards, vertical downwards, vertical upwards). Second, the cutting environments were investigated for dry, flood coolant, and compressed chilly air coolant cutting. The experiments were performed for various hardened materials and various coated tools. The results show that the cutting environment using compressed cilly air coolant provided better tool life than the flood coolant or the dry.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.343-348
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• 2000

The term‘High Speed Machining’has been used for many years to describe end milling with small diameter tools at high rotational speeds. typically 10,000 - 100,000 rpm. The process was applied in the aerospace industry for the machining of light alloys, notably aluminium. In recent years, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. And the end-mill is an important tool in the milling process. A typical examples for the end mill is the milling of pocket and slot in which a lot of material is removed from the workpiece. Therefore the proper selection of cutting parameters for end milling is one of the important factors affecting the cutting cost. The one of the advantages of HSM is cutting thin-wall part of light alloy like Al (thinkness about 0.3mm). In this paper, firstly, we study characteristics of HSM, and then, we choose the optimal parameters(cutting forces) and investigate various machining strategies to cut thin-wall part by experiment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.965-969
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• 1997

Due to the high feed rate,high speed machining (HSM) provide a great potential of rationalization for the machining Dies and Moulds. But determination of cutting condition is very difficult, because cutting mechanism of high speed machining is very complicated,especially using ball end-mill. This paoer gives a report on selection of the optimal cutting condition to improve the machining efficiency, And optimal machining condition is determined through the cutting force, FFT analysis of cutting force and surface roughness according to the cutting condition. Based on this experiment result,wear process and machining characteristics are evaluated.

• 한국공작기계학회논문집
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• 제10권6호
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• pp.126-134
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• 2001

Recently, high productivity and cost reduction becomes the most important target of industries due to the worldwide economic competition. One of these efforts is High Speed Machining(HSM), which reduces machining time with the increase of machining speed such as cutting speed and feedrate. It is very important, especially in case that the portion of machining time in production cost is high. This research suggests optimum cutting conditions to reduce cutting time with minimizing term error. For this study, a comprehensive model representing the texture of machining surface is developed, including rubbing phenomenon on the tip of ball end mill and expanded fibbing zone trajectory caused by tool deflection. Experiments show that the suggested set of feed and pick feed is optimum for maintaining the surface roughness identified by rubbing and low cutting speed in minimum.

• 한국정밀공학회지
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• 제18권10호
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• pp.208-213
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• 2001

High speed milling(HSM) is one of the emerging cutting process having tremendous potential not only in increased metal removal rates but also in improved surface finish, burr free edge, dimensional accuracy and a virtually stress free component after machining. The High efficiency and accuracy in machining of die/mold materials can be obtained in high speed machining, so it is necessary to analytic the mechanism of high speed cutting process : cutting force, acoustic emission signal.

• International Journal of Precision Engineering and Manufacturing
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• 제3권4호
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• pp.31-36
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• 2002

A continuous tool-path, that is to cut continuously with the minimum number of cutter retractions during the cutting operations, is developed in order to minimise the fluctuation of cutting load and the possibility of chipping on the cutting edge in HSM (high-speed machining). This algorithm begins with the offset procedure along the boundary curve of the sculptured surface being machined. In the of offset procedure, the offset distance is determined such that the scallop height maintains a constant roughness to ensure higher levels of efficiency and quality in high-speed machining. Then, the continuous path is generated as a kind of the diagonal curve between the offset curves. This path strategy is able to connect to neighbor paths without cutter retractions. Therefore, the minimum tool retraction tool-path can be generated And, it allows the sculptured surface incorporating both steep and flat areas to be high-speed machined.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1418-1423
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• 2004

High speed machining experiment on the heat-treated mold steel(STAVAX and CALMAX of hardness HRc 53) is carried using TiAlN coated ball endmill. Tool life and wear characteristics under the various machining parameters and cooling methods are investigated. Effect of cooling method on life and wear of the tool was compared. For most cases, tool life was not determined by the amount of wear but by th chipping on the cutting edge. It is found that tool manufacturer's cutting parameters generally agrees with the results of this experiment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 춘계학술대회 논문요약집
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• pp.208-208
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• 2004

공작기계와 절삭 공구의 발달로 고속 가공(high speed machining)의 도입이 가속화되고 있다. 고속 가공은 소재 제거율(MRR; material removal rate)을 향상시킴으로써 생산비용 및 생산 시간의 단축이 가능하며, 소경 공구를 이용한 고속 고회전 가공으로 고정밀 가공이 가능한 방법으로 생산 효율성 및 정밀성의 증대를 동시에 추구할 수 있는 가공 방법이다. 고속 가공에서 공구의 절입 및 퇴출 시에 급격한 절삭력의 변화로 인하여 공구의 파손(breakout) 및 칩핑(chipping)의 발생 가능성이 보다 높다.(중략)

• 한국기계가공학회지
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• 제2권3호
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• pp.5-12
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• 2003

In order to reduce the lead-time and cost, many useful methods have been applied to rapid prototyping (RP) in recent years. But cutting process is still considered as one of the effective RP methods that have been developed and currently available in the industry. It also offers practical advantages in aspects of precision and versatility. However, traditional 3-axis NC machining has some inherent limitations such as the restriction of tool accessibility and the complex setup. In this work, a new rapid prototyping system with high speed 5-axis machining of plastics has been developed to overcome those limitations. And cutting experiments were conducted to determine the design factors of the system and the cutting conditions of plastics. The architecture of developed system is described in detail and the successful application examples are presented.