• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.3
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• pp.83-91
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• 1999

In this paper, we suggest a virtual machining system that can simulate cutting forces of ball end milling at the stage of part design. Cutting forces, here, are estimated from the machanistic model that uses the concept of specific cutting farce coefficient. To this end, we need undeformed chip thickness which is used for calculating chip load. It is derived from the Z-map data of a CAD model. That is, chip load is the height difference between the cutting tool and the workpiece at an arbitrary position. The tool contact point is referred from the cutter location data. On the other hand, the workpiece height is acquired from the Z-map model of a CAD data. From the experimental verification, we can simulate machining process effectively to the slot and the side cutting of ball end mill.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.6
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• pp.84-91
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• 2003

In metal cutting operation, it is very important that predict cutting force and work surface. Vibration is an unstable cutting phenomenon which is due to the interaction of the dynamics of the chip removal process and the structural dynamics of machine tool. When vibration on, it reduces tool life, results in poor surface roughness and low productivity of the machining process. In this study, the experiments were conducted in machining center without cutting fluid to investigate the phenomenon of vibration. In the experiments, accelerometers were set up at the tail stock and tool holder and signals were picked up. Surface roughness profiles are generated under the ideal condition and the occurrence of vibration based on the surface shaping simulation model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.942-946
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• 1997

In this research,we suggest a virtual machining system that can simulate sutting forces at the stage of design. Cutting forces,here, are modeled form the machanistic model of the ball end milling. To this end, we need undeformed chip thickness which is used for calculating chip load. It is derived form the z-map data of a CAD model. That is, chip load is the height difference between the cutting tool contact point and the workpiece at arbitrary position. The tool contact point is referred from the cutter location. Form the experimental verification, we can simulate machining process effectively to the slot and the side cutting of ball end mill.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.4
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• pp.20-29
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• 2004

A Tool wear monitoring system is indispensable for better machining productivity with guarantee of machining safety by informing the tool changing time in automated and unmanned CNC machining. Different from monitoring using other signals, the monitoring of spindle current has been used without requiring additional sensors on machine tools. For the reliable tool wear monitoring, current signal only of tool wear should be extracted from other parameters to avoid exhaustive analyses on signals in which all parameters are fused. In this paper, influences of force components of parameters on measured spindle current are investigated and a hybrid approach to cutting force regulation is employed for tool wear signal extraction in the spindle current. Finally, wear levels are verified with experimental results by means of real-time feedrate aspects changed to regulate the force component of tool wear.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.2
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• pp.10-17
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• 2009

Transillumination system used by radiation is widely applied to industrial imaging system. In this study, the linear detector array constructed with scintillator and pin diode, and a multi-channel data acquisition system was developed for precision inspection of end-milling. The detector module consists of $16-CdWO_4$crystal scintillator and photodiode array. The detector and data acquisition system was applied to precision inspection of end-mill and the images of the end-mill were successfully reconstructed. The total system can analyze the Detector Quantum Efficiency(DQE) of each system. The performance of developed photodiodes equipment was compared with each other for different crystal geometry and its characteristics. Finally fine details of the end-mill phantom were constructed for industrial application. The image acquired contains several objects on a real time data transfer and the linear X-ray scanning system can be applied to many fields of a industry.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.1-7
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• 2016

In the present study, a plastic surface end-milling was implemented to investigate the effects of processing parameters on surface quality. The end milling can be considered an efficient method for rapid prototyping of thermoplastic bio-systems since it exhibits several beneficial functions including short fabrication time and high dimensional accuracy. In this regard, putative biocompatible thermoplastic materials, such as PMMA, PET, and PC, were chosen as workpiece materials. Among the relevant processing parameters influencing the surface quality of the final product, depth of cut, feed rate, and spindle speed were considered in the present study. The roughness of surfaces machined under various conditions was measured to elucidate the effect of each parameter. We found that the cut depth was the most significant factor. Heat generation during machining also had a remarkable effect. From these investigations, an appropriate combination of processing conditions specific to each type of use and end-product could be found. This optimization can be useful in end-milling of thermoplastic bio-systems.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.513-525
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• 1990

This paper presents Adaptive Robust Servocontrol(ARSC) scheme, which is an explicit(or indirect) pole-assignment adaptive algorithm with the property of "robustness". It guarantees asymptotic regulation and tracking in the presence of finite parameter perturbations of the unknown plant(or process) model. The controller structure is obtained by transforming a robust control theory into an adaptive control version. This controller structure is combined with the model estimation algorithm which includes a dead-zone for bounded noise. It is proved theoretically that this combination of control and identification is globally convergent and stable. It is also shown, through a real-time simulation study, that the desired closed-loop poles of the augmented system can be assigned directly, and that the adjustment mechanism of the scheme tunes the controller parameters according to the assigned closed-loop poles.oop poles.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.10
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• pp.60-67
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• 2019

Recently, lightweight materials such as Ti alloys have been used increasingly in the aerospace and high-tech industries for weight loss and fuel efficiency. Because of built-up edges and workpiece deflection due to low stiffness, the Ti alloys have poor machinability. In our study, systematic experiments were conducted to investigate the milling characteristics of the Ti alloy (Ti-6A1-4V) with endmills. The independent variables in the experiment were spindle speed, feed per tooth, and axial depth. Cutting force, acceleration RMS, and surface roughness were measured. Using the response surface method, the optimal cutting conditions were analyzed to improve machining quality and productivity.