• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1033-1037
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• 1997

In the end milling process, the information of axial and depths of cut plays an important role in adaptive control systems for precision machining and tool monitoring systems for unmanned machining. In general, it is not easy to know the depths of cut due to irregular shape of workpieces, inaccurate positioning of them on the table of machine tool and machining error in previous cutting. In addition to, even they are informed, it is difficult to match the individual position of the cutter on the varying shape of the work material. This work suggest an algorithm estimating the depths of cut based on cutting force sigal. The proposed algorithm can be applied in more extensive cutting situations, for example, presence of the tool wear, variation of work material hardness, etc.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.34-38
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• 2000

The trend of cutting process today goes toward higher precision and higher efficiency. Many thermal/frictional troubles occur in high-speed machining of die and mold steels.In this paper, the thermal characteristics are evaluated in high sped ball end-milling of hardened steel(HRc42). Experimental work is performed on the effect of cutting environments on tool life and cutting temperature. Cutting environments involve dry, wet(20bar), compressed chilly air at -9$^{\circ}C$, compressed chilly air at -35$^{\circ}C$. The measuring technique of cutting temperature using implanted thermocouple is used. The cutting temperature is about 79$0^{\circ}C$, 35$0^{\circ}C$ and 54$0^{\circ}C$ in dry, wet and compressed chilly air at +9$^{\circ}C$, respectively. The tool life for compressed chilly air at -9$^{\circ}C$ is longer than all other cutting environments in experiment.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.35-42
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• 2006

Although the conventional contour parallel tool path obtained from geometric information has been successful to make desirable shape, it seldom consider physical process concerns like cutting forces and chatters. In this paper, an optimized contour parallel path, which maintains constant MRR(material removal rates) at all time, is introduced and the result is verified. The optimized tool path is based on a conventional contour parallel tool path. Additional tool path segments are appended to the basic tool path in order to achieve constant cutting forces and to avoid chatter vibrations at the entire machining area. The algorithm has been implemented for two dimensional contiguous end milling operations with flat end mills, and cutting tests were conducted to verify the significance of the proposed method.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.2
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• pp.91-99
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• 1998

This paper presents a methodology for identifying the cutter runout geometry in end milling process. Cutter runout is common but undesirable phenomenon in multi-tooth machining because it introduces variable chip loading to insert which results in a accelerated tool wear. amplification of force variation and hence enlargement vibration amplitude From understanding of chip load change kinematics, the analytical cutting force convolution model was formulated as the angular domain convolution model was formulated as the angular domain convolution of three dynamic cutting force component functions. By virtue of the convolution integration property, the frequency domain expression of the local cutting forces and the chip width density of the cutter. Experimental study is presented to validate the analytical model. This study provides the in-process monitoring and compensation of dynamic cutter runout to improve machining tolerance and surface quality for industrial application.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.5
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• pp.45-52
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• 2002

In an end milling process, the undeformed chip section area and cutting forces vary periodically with the phase change of the tool. However, the real undeformed chip section area deviates from the geometrically ideal one owing to the cutter runout and tool shape error. In the current study, a method of estimating the real undeformed chip section area which reflects the cutter runout and tool shape error is presented during up-end milling processes of Inconel 718. The specific cutting forces, $K_r$ and $K_t$ are defined as the radial and tangential cutting forces divided by the modified chip section area, respectively. Both of the $K_{r}$ and $K_t$ values become smaller as the helix angle increases from $30^{\circ}$ to $40^{\circ}$. Whereas they become larger as the helix angle increases from $40^{\circ}$ to $50^{\circ}$. The $K_r$ and $K_t$ values show a tendency to decrease with increase of the modified chip section area.a.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.209-212
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• 2002

The wear process of end mill is a so complicated process that a more reliable technique is required for the monitoring and controling the tool life and its performance. This research presents a new tool wear monitoring method based on the sound signal generated on the machining. The experiment carried out continuous-side-milling for 4 cases using the high-speed steel slot drill under wet condition. The sound pressure was measured at 0.5m from the cutting zone by a dynamic microphone, and was analyzed at frequency domain. The tooth passing frequency appears as a harmonics form, and end mill wear is related with the first harmonic. It can be concluded from the result that the tool wear is correlate with the intensity of the measured sound at tooth passing frequency estimation of end mill wear using sound is possible through frequency analysis at tooth passing frequency under the given circumstances.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.1067-1082
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• 1991

본 연구에서는 비교적 강성이 약한 볼 엔드밀 공구에 있어서 처짐으로 인한 그 가공 특성을 알기 위하여, 변화된 칩 두께 및 처짐 모델로부터 절삭력을 예측하며 또한 절삭력에 의한 공구의 처짐으로 인하여 공구의 플랭크 부위와 공작물간의 발생하 는 간섭 특성을 고찰하고, 이러한 특성이 절삭성과 가공 오차에 미치는 영향을 실험을 통하여 분석하여 본다.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.2
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• pp.123-134
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• 1995

In this paper, the fast force algorithm has been studied so that it is used to calculate cutting forces and to develope the NC verification system. The NC verification using the fast force algorithm can verify excessive cutting force which is the cause of deflection and breakage of tool, and adjust the feed rate and spindle speed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.14-18
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• 2001

Rise in cutting force causes tool damage and worsens product quality resulting in machining accuracy deterioration. Especially, fragile material cutting brings about breakage of material and worsens product surface quality. In this study, we trace the locus of cutting force and examine the machined surface corresponding to the cutting force loci. and build up a monitoring system for deciding normal operation or not of cutting process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.1
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• pp.7-14
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• 2004

Machining error is defined the normal distance between designed surface and actual tool path with tool deflection. This is inevitably caused by the tool deflection, tool wear, thermal effect and machine tool errors and so on. Among these factors, tool deflection is usually known as the most significant factor of machining error. Tool deflection problem is analyzed using Instantaneous horizontal cutting forces. The high quality and precision of machining products are required in finishing. In order to achieve these purposes, it is necessary work that decrease the machining error. This paper presents a study on the machining error caused by the tool deflection in ball end milling of 2 dimensional surface. Tool deflection model and simple machining error prediction model are described. This model is checked the validity with machining experiments of 2 dimensional surface. These results may be used to decrease machining error and tool path decision.