• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.892-897
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• 2000

In this study, tap wear was analyzed not only to predict the tap life time but also to propose an improved tap design. Because rake angle and thread relief of tap are the significant factors in geometry of tap, these two factors were picked as the experiment variables. The experiment was conducted with six types of tap which have 6$^{\circ}$ , 8$^{\circ}$ and 12$^{\circ}$ of rake angles with 0,08mm and 0.14 mm of thread relief. From the measured cutting force, it could be known that cutting torque was low at the large the rake thread relief and tool life was long as rake angle became large. Eventually, tool life is longest when rake angle is 12$^{\circ}$ and the with 0.08mm thread relief. Aand the width of crater wear and that of flank wear were measured when a tapping torque was 20 [$kg_f$-mm] . Most of the measured values were above the width of tool wear[$V_B$=O.O3m], which means that tool life is over.

• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.67-72
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• 1994

Tool test was conducted to investigate the were process of only flank face TiN coated HSS tool in interrupted cutting for variuos cutting speeds and feed rates. Flank wear was caused by microchipping at the cutting edge. At high cutting speed, the which was formed as a result of diffusion and abrasion lowered cutting edge and influenced flank were. Flank wear due to chipping was little influenced by cutting speed.

• 한국생산제조학회지
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• 제4권2호
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• pp.46-53
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• 1995

In this study, Wear of a ceramic cutting tool for hardened STD11 steel was investigated. Under the finish machining condition. DOC notch wear of a ceramic cutting tool was mostly occurred earlier than flank and crater wear were proceeded. The relations of DOC notch wear, which was characteristically produced at the beginning of cutting. to cutting speed, feed, depth of cut, and nose radius of a ceramic cutting tool were examined. Effective approach angle, which is a function of cutting conditions, and boundary area were suggested, and then the influence of those was investigated, The following conclusions were obtained: (1)as cutting speed was increasing. DOC notch wear was decreasing (2) the cutting condition that magnitude of slendermess ratio was made small, was favorable for DOC notch wear, (3) as depth of cut was smaller, the influence of feed on DOC notch wear was also smaller, (4) DOC notch wear was mainly influenced by effective approach angle, but by boundary area in the range of low feed.

• 대한금속재료학회지
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• 제48권7호
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• pp.651-659
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• 2010

When high-speed interrupted cutting is carried out for die and mold steels with high hardness, CBN tools manifested a significantly longer wear life than carbide, ceramic, or cermet tools in an experiment of face milling characteristics. In addition, it was also found that they secured a stable surface roughness within a range of 1.6 S~6.3 S, an acceptable range for precision machining for polished machining parts. And it makes them acceptable in the precision machining field, except in industries where very high machining accuracy is required. In the high hardness interrupted cutting, it was advantageous to perform a negaland treatment and a honning treatment on the tools' cutting edge to extend tool life and surface roughness. Also, severe crater development was found on the sloped face in CBN tools following high-speed machining. This caused the cutting edge to be weakened and damaged, and ultimately resulted in a shorter tool life. Finally, as a result of EDX mapping inspection, Cr component was detected evenly on the entire crater wear area, which can be included only in STD 11.

• 열처리공학회지
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• 제7권3호
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• pp.199-205
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• 1994

The fracture characteristics and tool life of ceramics and WC, CBN cutting tool when turning heat treated steel STD11($H_RC$ 60) were investigated experimentally to clarify the machinability and optimum tool materials in cutting of difficult-to-cut material with high hardness. Forthermore, the behaviors of the tool wear and failure were examined with regard to cutting force. The hardened steel wore the cutting tool edge rapidily and increased the cutting forces, especially radial force. The tool was worn by the abrasive action. Flank Weat of $Al_2O_3-TiC$ ceramic and WC tool become relatively large and CBN & $Al_2O_3$, ceramic tool had a long life among the tool materials tested. The tool fracture patterns were just like minor cutting wear, flank wear, crater wear, notch wear, chipping. Flank wear rate was accelerated by occurrence of chipping. During the proceeding of machining, it was possible to foresee the catastrophic fracture of tool by abrupt increase of radial force.

• 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.

• 한국정밀공학회지
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• 제11권1호
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• pp.71-79
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• 1994

The aim of this study is to analyze the behavier of SUS 304 during the cutting process and the resulting cutting temperaturce. Since SUS 304 is a difficult-to-machine material, tool damage is largely affected by the suitability of cutting conditions. Therefore, in varying such cutting conditions, the experiment investigates the relations between cutting temperature and tool wear during the cutting process. All the cutting temperature data were manipulated successfully, and the tool temperature distributions were analyzed by a finite element method based on the acquisition data. In the results, the characteristics of cutting temperature are related to the difficulty of machining characteristics.

• 한국정밀공학회지
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• 제8권3호
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• pp.44-54
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• 1991

A Study was made on falnk wear in carbide tools in turning SUS304 steel. When an austenitic stainless steel (SUS304 steel) is cut with the tool, saw-toothed chip are produced. It is found that machining SUS304 steel would make a tool worn fast. For increasing productivity, tool wear has to be predicted and controlled. An amended cutting geometry consisting of a negative rake angle ($-6^{\circ}$ ) and a high clearance angle ($-17^{\circ}$ ) is proposed for decreasing carbide tool wear (flank) in the machining of SUS304 steel. The amended cutting geometry is found to make the flank wear lower than a general cutting geometry (rake angle $6^{\circ}$ , clearance angle $5^{\circ}$). The effects of the three cutting variables (cutting speed, feed, tool radius) on the flank wear analyzed by fiting a simple first-order model containing interaction terms to each flank wear parameter by means of regression analysis and the predicted from first-order regression analysis model equation of flank wear.

• 대한기계학회논문집A
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• 제28권2호
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• pp.196-205
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• 2004

The cutting characteristics and the deformed layer of nitrogen(N)-added type 316LN stainless steel were comparatively investigated to type 316L stainless steel. The cutting force, the surface roughness(Ra) and the tool wear in face milling works were measured with cutting conditions, and the deformed layers were obtained from micro-hardness testing method. The cutting resistance of type 316LN was similar to type 316L in spite of its high strength. The surface roughness of type 316LN was superior to type 316L for all the cutting conditions. In particular, in the high cutting speed above 345m/min, the surface roughness of the two stainless steels was closely same. The deformed layer thickness of the two stainless steels was generated in the 150$\mu\textrm{m}$-300$\mu\textrm{m}$ ranges, and its value of type 316LN was lower than that of type 316L. This is due to the high strength properties by nitrogen effect. It was found that type 316LN was higher in the tool wear than that type 316L, and flank wear was dominant to crater wear. In face milling works of type 316LN steel, tool wear is regarded as a important problem.