• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.12
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• pp.1322-1329
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• 2004

End-milling has been used widely in industrial system because it is effective to a material manufacturing with various shapes. Recently the end-milling processing is needed the high-precise technique with good surface roughness and rapid time in precision machine part and electronic part. The optimum mechanical vibration of main spindle, surface roughness and cutting temperature have an effect on end-milling condition such as, cutting direction, revolution of spindle, feed rate and depth of cut, etc. Therefore, this study carried to decide the working condition for optimum mechanical vibration of main spindle, surface roughness and cutting temperature using design of experiments, ANOVA and characteristic function. From the results of experimentation, mechanical vibration has an effect on revolution of spindle, radial depth of cut, and axial depth of cut. The surface roughness has an effect on cutting direction, revolution of spindle and depth of cut. And then the optimum condition used design of experiments is upward cutting In cutting direction, 600 rpm in revolution of spindle, 240 mm/min in feed rate, 2 mm in axial depth of cut and 0.25 mm in radial depth of cut. By design of experiments and characteristic function, it is effectively represented shape characteristics of mechanical vibration, surface roughness and cutting temperature in end-milling.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.6
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• pp.709-715
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• 2011

Chattering in cutting operations are usually a cumbersome part of the manufacturing process in mechanical. Particular, machining performance such as that of the boring process is limited by cutting condition at the movable components. Among various sources of chatter vibration, detrimental point in cutting condition is found a mechanical condition on overhang. It limits cutting speed, depth, surface roughness and tool wear failure as result because the all properties are varying with the metal removal process. In this case, we have to observe the resonance frequencies of a boring bar for continuous cutting. In the established research, boring bar vibration of cutting system has been measured with the aid of accelerometer. However, the inherent parameters of internal turning operations are severely limit for the real time monitoring on accelerometers. At this point, this paper is proposed other method for real time monitoring during continuous cutting with optical fiber at the inside of boring bar. This method has been used a plastic fiber in the special jig on boring bar by based on experimental modal analysis. In this study, improvement of monitoring system on continuous internal cutting was attempted using optical fiber sensor of inside type because usually chattering is investigated experimentally measuring the variation in chip thickness. It is demonstrated that the optical fiber sensor is possibility to measure of chattering with real time in boring process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.2
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• pp.28-33
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• 2007

This paper describes development of low cost precision machine that has a vacuum chuck. This study mainly aims to find out a cutting condition for maintaining optimum surface condition and to examine cutting characteristics of the precision machine that is equipped by diamond bites. The cutting materials is oxygen free copper. Several experiments were carried out to find out the main factors that affect the surface roughness such as principal axis RPM(rotation per minute), feeding speed, and cutting depth. As a result, we obtain The optimum cutting condition of the developed precision machine.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.295-300
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• 2010

Inconel 718 alloy, widely used as material of aircraft engine, has a good mechanical property in high temperature, strong anti-oxidation characteristics in oxidated current over $900^{\circ}C$, and also is not easily digested in the air containing sulfur, therefore, its usage as mechanical component is expanding rapidly. Even though Inconel alloy 718 is difficult to machine, it requires highly precise processing/machining to sustain its component quality of high accuracy. In this paper, general turning operation conditions arc tested to select the best cutting process condition by measuring surface roughness through implementing experiments with orthogonal array of cutting speed, feeding speed and cutting depth as processing parameters based on the Taguchi method. Optimal turning operation conditions are extracted from the proposed experimental models.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.98-104
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• 2012

In this paper, precision processing is carried out for the pre hardened steel(HRC 54), which is one of injection mould materials. Processing characteristics are estimated according to the number of tool cutting blade and roundness is observed by the 3-Dimensional measuring machine. The surface roughness affected by the wire electric discharge machining are measured. Cutting component force of STAVOX is the highest in condition of 2F processing because load per a blade of cutting tool is high. Especially, the difference in Fz is over 20N by cutting load. The slower spindle rotation speed and tool feed rate are, the better cutting component force is. The roundness of hole processed in condition of 4F is good because feed rate is able to be fast. When rotation speed is increased, the surface roughness is decreased. The surface roughness acquired in condition of 2F processing is higher about 50% than 4F processing.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.15-20
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• 2004

Inclined surface milling in the mould and die industries is one of the most commonly needed cutting process. For the variety and complexity of cutting characteristics in various cutting condition, it is difficult to select a optimal tool path orientation. The comparative results through FFT analysis in this study provide a guideline for the selection tool path orientation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.209-215
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• 2005

The dimensions and forms of precise machined parts are different to kinds of machine. It will be variant according to machine wear, tool form, cutting method and cutting condition at the same machine. At that time, the most important things are controlled and measured by appropriate measuring instruments. This paper aims to contribute to improving measurement accuracy through evaluation and consideration about various roundness in the machining company.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.120-126
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• 2002

The needs of ultra-precisely machined parts are increasing more and more. But the experimental data required to ultra precision machining of nonferrous metal is insufficient. The behavior of cutting in micro cutting area is different from that of traditional cutting because of the size effect. Copper is widely used as optical parts such as LASER reflector's mirror and multimedia instrument. In experimental, after oxygen-free copper is machined by ultra precision machine with natural mono crystal diamond tool (NCD) and synthetic poly crystal diamond tool (PCD), we compared chip formation and tool's wear according to used tool. Also, we researched optimized cutting condition with the results measured according to cutting condition such as spindle speed, feed rate and depth of cut. As a result, the optimal working condition that makes good surface roughness is obtained. The surface roughness is good when spindle speed is above 80 m/min, and feed rate is small and depth of cut is above 0.5 ${\mu}{\textrm}{m}$. In cutting of klystron anode and cavity 3.2 nmRa of surface roughness is obtained.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.426-429
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• 2003

In this study, phase transformation characteristics of Nitinol shape memory alloy with 54.5wt%Ni-45.5wt%Ti were investigated by varying with annealing treatment and cutting conditions through DSC(differential scanning calorimetry). Annealing treatment conditions were considered as heat treated time of 5 min, 15 min, 30 min, and 45 min, heat treated temperature of 40$0^{\circ}C$, 50$0^{\circ}C$, 5$25^{\circ}C$, 55$0^{\circ}C$, 575$^{\circ}C$, $600^{\circ}C$, $700^{\circ}C$, 80$0^{\circ}C$, and 90$0^{\circ}C$, and environmental condition of heat treatment under vacuum or air. Cutting conditions were considered as no cutting, one side cutting, and two side cutting. Tensile test was also conducted on Nitinol shape memory alloy to investigate thermomechanical characteristics by varying with annealing heat treatment histories. According to the results, annealing treatment and cutting conditions were found to significantly affect on phase transformation and thermomechanical characteristics of Nitinol shape memory alloy.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.11
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• pp.25-31
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• 1996

In this paper, three different types of commercial tools -P20, NC123K and ceramic- have been used to cut austempered ductile iron(ADI). In the austempered condition the materials are hard, strong and difficult to machine. Thus, we selected a optimum tool material among three different types of used tools in machining of austempered ductile iron. It was used acoustic emission (AE) to know cutting characteristic for selected tool and investigate characteristic of AE signal according to cutting condition and relationship between AE signal and flank wear land of the ceramic tool. The obtained results are as follows ; (1) The ceramic tool among three different types of tools is the best in machining austempered ductile iron. (2) In case of ceramic tool, the amplitude level of AE signal(AErms) is mainly affected by cutting condition and it is proportional to cutting speed. (3)There have been the relationship of direct proportion between the amplitude level of AE signal and flank wear land of the tool. (4) It was observed that the value of AErms was only affected by cutting speed. Therefore it is possible to in-process detec- tion of ceraic tool's wear in case the initial value of AErms at each cutting speed decided.