• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.6
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• pp.16-21
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• 2005

The cutting characteristics of hardened steel(AISI 52100) by PCBN tools is investigated with respect to cutting force, workpiece surface roughness and tool flank wear by the vision system. Hard Owning is carried out with various cutting conditions; spindle rotational speed, depth of cut and feed rate. Backpropagation neural networks(BPNs) are used for detection of tool wear. The input vectors of neural network comprise of spindle rotational speed, feed rates, vision flank wear, and thrust force signals. The output is the tool wear state which is either usable or failure. The detection of the abnormal states using BPNs achieves $96.8\%$ reliability even when the spindle rotational speed and feedrate are changed.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.12
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• pp.120-129
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• 1995

This study introduces a tool wear monitoring technology in face milling operation comprised of an unsupervised neural network. The monitoring system employs two types of sensor signal such as cutting force and acceleration in sensory detection state. The RMS value and band frequency energy of the sensor signals are calculated for te input patterns of neural network. ART2 neural network, which is capable of self organizing without supervised learning, is used for clustering of tool wear states. The experimental results show that tool wear can be effectively detected under various cutting conditions without prior knowledge of cutting processes.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.3
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• pp.5-14
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• 1995

In recent years, the automization of cutting machine tools has been developed very fast. Hance, the in-process detection of cutting condition is very important for automatic manufacturing system in factory. Acoustic Emission(AE) has been widely used in monitoring the cutting conditions, because of high sensitivity of AE signal and low cost of AE equipment. This experimental study deals with the relations between AE signal, cutting force charcteristics and tool wear in the machining of SUS304. Face milling operation is used for the analysis between tool wear and AE signal.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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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.

• Journal of the Korean Society for Precision Engineering
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• v.7 no.2
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• pp.47-57
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• 1990

In-process recognition of the cutting states is one of the very important technologies to increase the reliability of mordern machining process. In this study, practical methods which use the dynamic component of the cutting force are proposed to recognize cutting states (i.e. chip formation, tool wear, surface roughness) in turning process. The signal processing method developed in this study is efficient to measure the maximum amplitude of the dynamic component of cutting force which is closely related to the chip breaking (cut-off frequency : 80-500 Hz) and the approximately natural frequency of cutting tool (5, 000-8, 000 Hz). It can be clarified that the monitoring of the maximum apmlitude in the dynamic component of the cutting force enables the state of chip formation which chips can be easily hancled and the inferiority state of the machined surface to be recognized. The microcomputer in-process tool wear monitor- ing system introduced in this paper can detect the determination of the time to change cutting tool.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.6
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• pp.90-96
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• 1998

The ductile cast iron is austempered at 300, 350 and 40$0^{\circ}C$ temperature in order to investigate the basic factors for monitoring drill wear in automatic production process, and cutting force and AE RMS signals are measured with changing cutting condition for ADI(Austempered Ductile Cast Iron) with different mechanical properties. The signals of cutting force were influenced by cutting speed and feedrate greatly. On the other hand AE RMS signals are influenced by cutting speed where as it is not related with feedrate. As the depth of drilling increases, cutting force shows a slow increase and the value of AE RMS increases until the range of h/d=4. But over the range it increases greatly due to an amount of chip discharge and friction with inner wall of drilling hole, etc. As the drill diameter increases at a constant depth of drilling. Cutting force increases linearly, but the level of AE RMS does not increases linearly due to circumferential velocity and great influence of h/d.

• Design & Manufacturing
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• v.16 no.3
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• pp.39-43
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• 2022

In this study, we designed an vibration cutting tool that can achieve improvements such as low cutting force, interrupted chip evacuation and better surface quality of cutting performance to obtain high-quality surface roughness and improvement of tool wear, which is an issue in the machining of high-hardness mold steel. Among the resonance frequency modes of the vibration cutting tool, the bending mode was used to maximize the driving amplitude of the vibration tool tip, and the resonance frequency was confirmed through the finite element method. After measuring the actual resonant frequency of the designed tool using an optical fiber sensor, the cutting force and machining surface of vibration cutting and conventional cutting were compared and analyzed in the turning process of high hardness mold steel (STAVAX). As a result of the experiment, the cutting force was reduced by about 20 % compared to the conventional cutting process, and the surface roughness was also improved by about 60 %. This study suggested that the tool wear and surface quality of high-hardness steel can be improved through the vibration cutting method in the machining of high hardness mold steel.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.95-100
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• 1995

Automatic monitoring of cutting process is one of the most important technology for increasing the stability and the reliability of unmanned manufacturing system. In this study, basic methods which use the acoustic emission (AE) signals and sutting forces proposed to monitor tool wear (flank wear) quantitatively. Fist, in order to detect flank wear, it was investigated influence of cutting conditions, that is, cutting velocity, feed and depth of cut, on AE signals (AErems) and cutting forces. Furthermore,the relationship flank wear between AErems and cutting forces were discussed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.4
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• pp.29-36
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• 2004

An experimental study on drilling of stainless steel is conducted using TiAlN coated drills and HSS twist drills with several cutting conditions; feed rate, spindle rotational speed, and dry/wet cutting. The effects of number of hole on the thrust force are examined by cutting force measurement. The flank wear of the drills and the change of hole diameter are quantitatively observed using a vision system. It is found that the thrust force in drilling with TiAlN coated drills decrease under dry and wet machining, whereas the flank wear resistance is improved.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.898-901
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• 2000

It is known that Si3N4 ceramic insert has less hardness than Al2O3 ceramic insert. But Si3N4 ceramic insert has not only high toughness and strength but also low thermal expansion coefficient, which makes it has longer tool life under thermal stress condition. In this study, commercial Si3N4 ceramic insert and home-made SiC-Si3N4 ceramic insert which has different sintering time and chemical composition is tested under various cutting conditions. The experimental result is compared in terms of tool life and cutting force. Generally, As the cutting speed and the feed rate increased, the cutting force and the flank wear increased too. The performance of SiC-Si3N4 ceramic insert shows the possibility to be a new ceramic tool.