• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.114-118
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• 1996

Evaluation of cutting condition is one of the most important aspect to improve productivity and quality. In this study, the wear and cutting characteristics(cutting force, acoustic emission signal and surface roughness) of ceramic cutting tool for hardened die material(SKD11) were investigated by experiment. Flank wear on relief face of tool was occurred more dominant than crater wear on rake face. Experiments were performed under the various cutting condition.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.317-322
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• 2004

This paper deals with a prediction method of tool life in view of the reliability assessment. In this study, the flank wear was studied among multi-factors deciding the tool wear state. Firstly, tool lift was predicted by correlation between flank wear and cutting time, based on the extended Taylor tool life equation of turning data, including parameters of cutting speed, feed rate, and cutting depth. Secondly, each of cutting conditions of endmilling was equivalently converted to apply ball endmill data to the extended Taylor equation. The web-based reliability prediction program for tool lift is being developed as one of reliability assessment programs to for the machine tools.

• 한국공작기계학회논문집
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• 제14권3호
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• pp.1-7
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• 2005

The prediction for tool life is one of the most important factors for increasing reliability, stability, and productivity of manufacturing system. This paper deals with a tool life prediction method in view of reliability assessment for cutting tools. In this study, flank wear was focused among multi-factors deciding the tool wear state. First, tool life was predicted by correlation between flank wear and cutting time, based on the extended Taylor tool life equation of turning, including parameters of cutting speed, feed rate, and cutting depth. Second, each of cutting conditions of end-milling was equivalently converted to apply ball end-mill data to the extended Taylor equation. The web-based prediction program for tool life was developed as one of reliability assessment programs for machine tools.

• 한국정밀공학회지
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• 제4권3호
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• pp.60-68
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• 1987

An optoelectronical method for in process monitoring of flank wear of cutting tools is presented. The method is based upon real-time vision technology in which the tool is illuminated by a beam of laser and then the image of wear zone is taken by a vidicon camera. The image is converted to a series of digital pixel data and processed through an algorithm specially developed for measurement of the wear land width. Detailed aspects of the prototype measurement system byilt for experiment are described, and test results are discussed. As conclusions, it is proved that the methods are effec- tive especially for-in situ application with a measuring accuracy of 0.01mm.

• 한국정밀공학회지
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• 제12권5호
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• pp.98-107
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• 1995

The in-process detection of drill wear and breakage is one of the most importnat technical problems in unmaned machining system. In this paper, the monitoring system is developed to monitor abnormal drilling states such as drill breakage, drill wear and unstable cutting using motor current. Drill breakage is detected by level monitoring. Tool wear is classified by fuzzy pattern recognition. The key feature for classification of tool wear is the estimated flank wear which is calculated by the proposed flank wear model. The characteristic of the model is not sensitive to the variation of cutting conditions but is sensitive to drill wear state. Unstable cutting states due to the unsmooth chip disposal and the overload are monitored by the variance/mean ratio of spindle motor current. Variance/mean ratio also includes the information about the prediction of drill wear and drill breakage. The evaluation experiments have shown that the developed system works very well.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.1021-1024
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• 2001

Out of all metal-cutting processes, the hole-making process is the most widely used. It is estimated to be more than 30% of the total metal-cutting process. It is therefore desirable to monitor and detect drill wear during the hole-drilling process. In this paper, the vision system of the sensing methods of drill flank wear on the basis of image processing is used to detect the wear pattern by non-contact and direct method and get the reliable wear information about drill. In image processing of acquired image, median filter is applied for noise removal. The vision flank wear area of the drill was measured. Backpropagation neural networks (BPns) were used for no-line detection of drill wear. The neural network consisted of three layers: input, hidden and output. The input vectors comprised of spindle rotational speed, feed rates, vision flank wear, thrust and torque signals. The output was the drill wear state which was either usable or failure. Drilling experiments with various spindle rotational speed and feed rates were carried out. The learning process was peformed effectively by utilizing backpropagation. The detection of the abnormal states using BPNs achieved 96.4% reliability even when the spindle rotational speed and feedrate were changed.

• 한국정밀공학회지
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• 제10권1호
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• pp.34-41
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• 1993

SUS304 is wellknown as difficult-to-machine materials. It is easy to appear workhardened, and workhardening is one of the causes of groove wear on the tool. In this paper, the author would like to compare the width of flank wear with that of groove wear, and to find whether the groove wear can be used as a criterion of a tool life. The design of the twelve tests provides three levels for each variable (speed: 200m/min, 118m/min, 70m/min; feed: 0.3mm/rev, 0.17mm/rev, 0.1mm/rev; depth of cut: 0.4mm, 0.28mm, 0.2mm). The study of tool-life testing by statistical technique follows usual most scientific sequence. So the tool-life predicting equation is calculated by the method of least squares. The overall adequacy of the model can be verified by the analysis of variance. The results obtained are as follows : 1) When SUS304 is cut in 200(m/min), the width of flank wear is much larger than that of groove wear. 2) In cutting speed 118m/min, flank wear is a little larger than groove wear and in the cutting speed 70m/min, the latter is a little larger so that it is reasonable to determine the tool life according the crierion by groove wear in the low cutting speed (less than 70m/min). 3) Owing to the burr the depth of engagement along the cutting edge is extended toward the shank.

• 한국정밀공학회지
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• 제13권12호
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• pp.151-157
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• 1996

The tool condition monitoring is one of the most important aspects to improve productivity and quality of workpiece. In this study, the wear of ceramic tool (A1$_{2}$0$_{3}$-TiC Series) cutting the hardened die material(SKD11) was investigated. Flank wear was more dominant than crater wear. Therefore the modeling of cutting force related to flank wear has been performed. The cutting force model was construct- ed by an assumption that the stress distribution on the tool face is affected by tool wear. The relationship between characteristics as cutting force and tool wear can be suggested by machining parameters depending on cutting conditions. Experiments were performed under the various cutting conditions to ensure the validity of force models. The theoretical predictions on the flank wear are approximately in good agreement with experimental results.

• 한국주조공학회지
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• 제42권3호
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• pp.191-197
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• 2022

This study aims to improve the machinability of gray cast irons in high speed cutting by using nonmetallic inclusions. In this research, small quantities of AL and Mg were added to conventional gray cast irons without influencing their mechanical characteristics and castability to investigate the effects of these nonmetallic inclusions in the gray cast irons on tool wear in high speed cutting. During the high speed turning of gray cast iron containing Al and Mg using a cermet tool, protective layers consisting of Al, Mg, Si, Mn, S and O were detected on the flank face and rake face of the tool, and flank and crater wear were significantly reduced compared to the turning of conventional gray cast iron and gray cast iron added with Al. The effect of inclusions on tool wear increased with increasing cutting speed, and flank and crater wear was the smallest at the cutting speed of 700m/min. Moreover, in face milling, the addition of Al and Mg drastically decreased the wear rate, and wear hardly progressed even in prolonged cutting length after initial wear. The amount of adhesion on tool faces increased as the cutting speed increased. This increase in cutting speed resulted in the formation of a thick protective layer and the reduction of tool wear. Furthermore, the addition of small amounts of Al and Mg prevented thermal cracks in the face milling of gray cast irons.

• 한국정밀공학회지
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• 제12권11호
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• pp.63-73
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• 1995

A mechanistic force system model considering the flank wear for the face milling process has been developed. The model predicts variation of the cutting forces according to flank wear in face milling over a range of cutting conditions, cutter geometries and cutting process geometries including relative positions of cutter to workpiece and rounouts. Flycutting and multitoth cutting teste were conducted on SS41 mild steel with sintered carbide tool. In order to verify the mechanistic force model considering the flank wear of cutting tools, a series of experiments was performed with single and multitooth cutters in various cutting conditions. The results show good agreement between the predicted and measured cutting force profiles and magnitudes in time and frequency domains.