• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2006.05a
• /
• pp.127-131
• /
• 2006

There are being a lot of studies for achievement of high speed Dehydration, high-strength and Lightweight of washing machine in the latest washing machine business. It is essential that Press-joining Strength of Spin Drum Seaming division is improved .to attain that target. Generally, we are using Mechanical press-joining by Seaming and T.I.G (Tungsten Inert Gas) welding among part joint method. Mechanical press-joining method that is mainly using for Stainless Steel (STS430) Drum have lots of merit that consumption of energy is low more than welding and production costs cut down and generation of the corrosion is solved by removing weld zone defect and materials having different properties are enable to join without special equipment. But, it is difficult to realize joint strength required at high speed operation because joint strength of mechanical press-joining method is low remarkably in comparison with welding. Also, there are a lot of analysis difficulties and very limited research is under way due to the dynamic factor such as multistage plastic working, elastic recovery, residual stress etc. The results of this study show optimal joining condition for mechanical press-joining by performing lots of tensile joining strength test with various specimen under multi-change of important design factor such as seaming width, bead area and bead depth etc.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.6
• /
• pp.1533-1541
• /
• 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
• /
• 2003.06a
• /
• pp.589-592
• /
• 2003

In the machining process of micros shape by using high-precision machining system and micro end-mill, it is important for machining characters of tools to be grasped in order to stably use tools of micro end-mill. In this study. we carried out an analytical experiment of basic machining features by using end-mill tools for the purpose of damage prevention and manufacture of high quality when the tools of micro end-mill are used. This experiment used a micro machining system with high precision and a variety of end-mill tools commercialized from tens to hundreds microns in diameter. To establish an optimal machining condition without tool damage, cutting force was analyzed according to the changes of tool diameter and cutting conditions such as cutting speed. feed rate, depth of cut. And an examination was performed for the shape and surface illumination of machining surface according to the changes of machining conditions. Based on these micro machining conditions, micro square pillar, cylinder shaft. thin wall with high aspect ratio, and micro 3-D structures such as micro gear and fan were manufactured.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.9
• /
• pp.55-62
• /
• 2003

This paper investigates the micro-cutting of cemented carbides using PCD (polycrystalline diamond) and PCBN (polycrystalline cubic boron nitride) cutting tools are performed with SEM direct observation method. The purpose of this study is to make clear the cutting mechanism of cemented carbides and the fracture of WC particles at the plastic deformation zone in orthogonal micro-cutting. And also to achieve systematic understanding, the effect of machining parameter on chip formation and machined surface was studied, including cutting speed, depth of cut and various tool rake angle. Summary of the results are shown below. (1) Three type of chip formation process have been proposed by the results of the direct observation in orthogonal micro-cutting of cemented carbide materials. (2) From the whole observation of chip formation, primary WC particles are crushed and/or fine grained in the shearing deformation zone. A part of them are observed to collide directly with a cutting edge of tool by following the micro-cutting. (3) Surface finish, surface morphology and surface integrity is good to obtain by cutting with PCD cutting tool compared with PCBN. (4) The machined surface has the best quality near the low cutting speed of 10${\mu}m$/sec with a cutting depth of 10 ${\mu}m$ using 0$^\circ$ rake angle and 3$^\circ$ flank angle in this condition, but it was found that excessively low speed, for example the extent of 1 ${\mu}m$/sec, is not good enough to select for various reason.

• Journal of the Society of Naval Architects of Korea
• /
• v.45 no.5
• /
• pp.562-568
• /
• 2008

In this study, the target FSICR class is 1A whose target thickness of the brash ice is 46 mm in model scale. Normally ice floes for brash ice do not exceed 2 m in full scale, so the model ice sheet was cut by about 10 cm by 10 cm using hand saws. Since the target thickness of brash ice is 46 mm, 46 mm ice sheet makes one layer brash ice. For 23 mm thickness ice sheet, two layers should be accumulated to reach 46mm brash ice thickness. For 15mm thickness ice sheet, three layers need to be accumulated as the same as those in 23 mm ice sheet. New methodology to produce a brash ice was proposed. The results showed that it would be important to use multi-layer rather than single layer possibly because of significant thrust deduction from the propeller-ice interaction in the present ice condition (FSICR 1A).

• The Plant Pathology Journal
• /
• v.22 no.2
• /
• pp.152-154
• /
• 2006

CSVd-infected chrysanthemum plants grown under $10^{\circ}C\;or\;15^{\circ}C$ growth chamber for 2 months resulted a higher dilution endpoint of template RNA for Reverse transcription and polymerase chain reaction (RT-PCR) than those grown for 1 month: $10^{-4}(1.35{\times}10^{-2}ug/ml)$ for 1 month, and $10^{-3}(1.35{\times}10^{-1}ug/ml)$ for 2 months. Independent experiment, shoots cut from CSVd (Chrysanthemum stunt viroid)-in footed chrysanthemum plants grown under $10^{\circ}C\;or\;20^{\circ}C$ growth chamber for 2 months showed the same CSVd concentration as control($30^{\circ}C$) at 8 weeks after moving them to normal green-house condition($30^{\circ}C$). From those results, it was concluded that even though the concentration of CSVd was reduced in plants grown at low temperatures, when they were moved to normal glass-house temperature CSVd concentration increased to that of untreated plants in 8 weeks. This conclusion was supported by the rapid replication of CSVd in chrysanthemum after infection.

• Journal of the Korean Home Economics Association
• /
• v.38 no.11
• /
• pp.137-149
• /
• 2000

The Purpose of this study was to investigate actual condition about the modem adaptation of interior elements(floor, wall, ceiling, door & window) in traditional thatched roof house. The examined objects were interior space of 36 restaurants and cafes in Seoul and Kyung-Ki Do area. 1. Floor: Jang-pan was mostly alternated with linoleum which huts Jang-pan pattem. Wumul-maru was adapted from the original and Jang-maru was alternated with wood or linolium which has western state Jang-maru pattern. Mud was adapted from the original or alternated with slate stone or rough finish cement. 2. Wall: Rice proper was alternated with rice paper book witch has chinese character, paper for parcels or modem wall paper. Plaster-white paint or white handy coat. Mud-mud color paint or bamboo stick witch located in the mud wall orginal. Log-half cut log. Wooden board-without cross bar or irregular form. 3. Ceiling: Yondung-Chongang was mostly adapted from the original and Banja-Chonjang was alternated with rice paper book which has Chinese character or modem wall paper. 4. Door and Window: Ttisal-mun and Panjang-mun were adapted from the original. Wan and A’character door and window were simplified character itself.

• Proceedings of the KIPE Conference
• /
• 2002.07a
• /
• pp.723-726
• /
• 2002

In this paper, a high efficiency leakage transformer for neon tube is developed to improve its power factor, to reduce its core loss and weight by using a technique of shape optimization and direction of grain-oriented silicon steel sheet. A protection circuit is designed for all types of neon transformer loaded with one or more neon lamps. Whenever the neon tube fails to be started up or comes to the life end, or encounters faults with open-circuits at the output terminals of the neon transformer, the protection circuit will be initiated to avoid more critical hazards. These neon transformers need a protection circuit to prevent from current stresses on circuit components by neon tube fail. The input of the transformer is automatically cut off when the abnormal condition occurs, preventing waste of no-load power. As the results of the study, the core weight is reduced by $11\%$, the power factor improved by $5\%$ and the efficiency increased by $6\%$ compared with the conventional type due to the employment of the grain-oriented steel sl)eel and the optimized core shape.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.17-18
• /
• 2006

Laser welding of metals has been widely used to improve a wear resistance and a corrosion resistance of the industrial parts. The objective of this research works is to investigate the influence of the process parameters, such as the welding for metals with CW Nd:YAG lasers. The bead-on-plate welding tests are carried out for several combinations of the experimental conditions. In order to quantitatively examine the characteristics of the butt welding, the welding quality of the cut section, stain-stress behavior and the hardness of the welded part are investigated. From the results of the investigation, it has been shown that the optimal welding condition without defects in the vicinity of the welded area and with a good welding quality is 1400W of the laser power, 0.8m/min, 0.9m/min of welding speed and $4{\ell}$ in of pressure for shielding gas.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.10a
• /
• pp.343-348
• /
• 2000

The term‘High Speed Machining’has been used for many years to describe end milling with small diameter tools at high rotational speeds. typically 10,000 - 100,000 rpm. The process was applied in the aerospace industry for the machining of light alloys, notably aluminium. In recent years, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. And the end-mill is an important tool in the milling process. A typical examples for the end mill is the milling of pocket and slot in which a lot of material is removed from the workpiece. Therefore the proper selection of cutting parameters for end milling is one of the important factors affecting the cutting cost. The one of the advantages of HSM is cutting thin-wall part of light alloy like Al (thinkness about 0.3mm). In this paper, firstly, we study characteristics of HSM, and then, we choose the optimal parameters(cutting forces) and investigate various machining strategies to cut thin-wall part by experiment.