• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1533-1541
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• 1990

Cubic boron nitride (CBN) is known the second hardest material followed diamond and was provided industry as an abrasive grain in the late 1960's. Since the introduction of CBN, a large amount of research has been carried out to determine the best application condition for grinding operation. Despite the advantages in its characteristics, CBN has not yet gained full acceptance as more excellent abrasive grain than traditional one. The reason for this state is that the surface roughness ground by CBN is worse than by traditional one and dressing and truing is very difficult. This led user's resistance to the use of CBN as an abrasive grain. Present study is to investigate the cause of lower surface roughness ground by CBN single crystal abrasive grain comparing with traditional one.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.363-366
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• 2003

The hard turning is a turning operation performed in high strength alloy steels (HRC>30) in order to reach surface roughness close to those obtained in grinding. This is possible because of availability of improved tool materials (polycrystalline cubic boron nitride. PCBN), ad more rigid machine tools. According to many previous work of hard turning mechanism, the maximum temperature of cutting can be raised up to 100$0^{\circ}C$. As the heat generation rate is very high, the thermal displacement of tool holder cannot be negligible. Therefore, the aim of this paper is to analyze effects of high heat generation at CBN tool tip to the thermal displacement of a tool holder in hard turning and finally geometric accuracy. The thermal behavior of a CBN tool holder is investigated by numerical simulation and experiment, and the result shows thermal elongation of microns order is possible during hard turning process.

• Journal of the Korean Society of Safety
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• v.23 no.5
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• pp.43-48
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• 2008

The magnetic polishing is the useful method to finish some machinery fabrications by using magnetic power. This method is one of the precision polishing techniques and has an aim for clean technology in the transportation of the pure gas in the clean pipes. The magnetic abrasive polishing method is not so common in the field of machine that it is not known to widely. There are only few researchers in this field because of non-effectiveness of magnetic abrasive. Therefore, in this paper deals with development of the magnetic abrasive using Ba-Ferrite. In this development, abrasive grain GC and CBN has been made by using the resin bond fabricated at low temperature. And magnetic abrasive powder was fabricated from the Ba-Ferrite which was crushed into 200 mesh. The XRD analysis result shows that only GC, CBN and Ba-Ferrite crystal peaks were detected, explaining that resin bond was not any more to contribute chemical reaction. From SEM analysis, we found that GC, CBN abrasive and Ba-Ferrite were strongly bonding with each other.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.55-63
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• 2003

In this study, an experimental research of grinding characteristics using super-abrasives for surface carburized and heat treated SCM415 materials, which were usually used to make a linear motion guide block and were comparatively hard-to-machine materials, was carried out. In order to conduct a high efficiency and a accuracy grinding of such materials, grinding processes using CBN (Cubic boron nitride) and 38P grinding wheels have been attempted on a surface grinding machine. The grindability according to each grinding conditions was evaluated by means of a grinding force, a surface roughness and a residual stress. The experimental methods and results were presented in this paper. And also, from a proposed truing method the CBN wheels that combined a copper and a break truer gave a full scope to the wheel's performance.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.12
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• pp.2279-2286
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• 1992

A hypereutectic Aluminum-Silicon Alloy is widely used in the parts of autombile because of high-resistance and good strength. In this study, the cutting of a hypereutectic Al-Si alloy (A390) for extraction of Si particle was experimentally investigated. By proper selection of cutting tool materials and optimization of cutting conditions, economical machining of this alloy is achieved. The surface roughness relates closely with the feed rate and cutting speed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.123-129
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• 2022

Quartz (SiO2) has high abrasion and heat resistances and excellent chemical and mechanical properties; therefore, it is used in various industries, such as machinery, chemistry, optics, and medicine. Quartz is a high-hardness and brittle material and is classified as the topmost difficult-to-cut material, which is because of the cracking or chipping at the edge during processing. Corner wear, such as cracks and chippings that occur during cutting, is a major cause for the deterioration in the machining quality. Therefore, many researchers are investigating various techniques to process quartz effectively. However, owing to the mechanical properties of quartz, most studies have been conducted on grinding, micromachining, and microdrilling. Few studies have been conducted on quartz processing. The purpose of this study was to analyze the machining characteristics according to the machining factors during the slot machining of quartz using a cubic boron nitride (CBN) tool and to select the optimal machining conditions using the Taguchi method. The machining experiment was performed considering three process variables: the spindle speed, feed rate, and depth of cut. The cutting force and surface roughness were analyzed according to the processing conditions.