• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.927-931
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• 1997

In process of the finish face milling of the hardended STD11 steel(H /sab r/ c50,55) by CBN tool, the optimum tool shape is suggested,which can minimize the tool fracture and by chipping by impact. The obtained results are as follows. (1) The optimal chamfer angel was about 25 .deg. , and the suitable chamfer width was 0.2mm. (2) The nose radius of tool was most excellent at 1.2mm in the viewpoint of tool wear and surface roughness. (3) Wear speed was effected by sintering method of CBN tool B.U.E

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.26-30
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• 1996

This paper presents the performance of CBN tools in the machining of hardened die-materials, SKD11 and SKD61 steel with HRC 50, by high-speed face milling. Generally, grinding or EDM is being used in machining of hardened materials but the cost is very high. If those can be replaced by cutting, it will be a greatly economical advantage. CBN tool has been recognized as an effective tool in turning, but it has not been in milling. So wear and surface roughness mode of CBN tool for hardened SKD11 and SKD61 steel were investigated by high-speed face milling in this study Also the relation between cutting force and wear mode of CBN tools was investigated.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.4
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• pp.27-35
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• 1998

Ni-based heat resisting alloys are commonly used for high temperature applications such as in aircraft engines and gas turbines. In this work, the machinability of Nimonic 263 alloy is investigated with respect to optimum tool type and cutting conditions for both continuous and discontinuous machining as well as weld region. Among the five types of tools tested, K25 tool experienced the least of damage in machining the weld region. Furthermore, despite their superior high temperature hardness, Si-Al-O-N and CBN tools peformed poorly in machining Nimonic 263.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.6
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• pp.86-97
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• 1994

An experimental investigation is reported on the wear mechanism of CBN cutting tools. The cutting experiments were conducted on a lathe equipped with a tool dynamometer for cutting force measurement. The investigation of wear mechanism was executed by observing the worn tools using tool microscope and scanning electron microscope. Results indicate that the flank wear occurs dominantly by abrasive wear mode and the crater wear by adhesive wear mode. The results also indicate that the width of flank wear is closely related with the passive component of cutting force.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.20-25
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• 1996

The needs to machine hardened steels with high productivity and good surface integrity have been increased in the dies ＆ molds industry. This paper presents some experimental results on the CBN ball endmilling for hardened tool steel. This investigation concerns on the effects of cutting speed and cutting fluids on the cutting performance such as cutting forces, tool wear, and surface finish. The wear of CBN ball endmill for each cutting conditions were also examined through the microscopic observation. It has been found out that the higher cutting speeds with cutting fluids result in better cutting performance.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.10
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• pp.157-163
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• 1997

The needs to machine hardened steels with high productivity and good sufrace integrity have been increased in the dies & molds industry. This paper presents some experimental results on the CBN ball endmilling for hardened tool steel. This investigation concerns on the effects of cutting fluids, cutting speed, and feed on the cutting performance such as cutting forces, tool wear, and surface finish. The wear of CBN ball endmill for each cutting conditions were also examined through the microscopic observation. It has been found that the higher cutting speeds with cutting fluids result in better cutting performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1078-1082
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• 1997

The use of CBN tool material has been greatil increased because of the superior metal cutting performance for the machining of hardened steels. This paper presents some experimental results on the ball endmilling of hardened steels. Three different hardnesses of STB-11 workpieces were machined using CBN ball endmills, and the machining charteristics including cutting forces, tool wear, and surface roughness of machined surface were compared. It has been found that the CBN ball endmill works better in the machining of harder workpieces. The microscopic examination explains that this unusual phenomenon is cause by the difference of microstructure of each workpieces.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.4
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• pp.1216-1224
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• 1996

In the use of glass fiber reinforced plastics it is often necessary to cutting the components, but the cutting GFRP is often made difficult by the delamination of composites and the short tool life. In this paper, the machinability of GFRP by mean of tool materials and type was experimentally investigated. By proper selection of cutting tool material and type excellent machining of this workpiece is achieved. The surface quality relate closely with the feed rate and cutting tools.