• Journal of Korean Society of Forest Science
• /
• v.40 no.1
• /
• pp.43-50
• /
• 1978

The elder berry was known to the rich in natural food colour resources and used in as for making wine, confectionary, perfumes, natural food colour, making elder berry juice, jelly, jam and medicinal properties or oils. In the present study, wish was to find the effect of various factors on the success of the vegetative propagation of elder berry by means cutting in the exposed field and green house was carried out and those obtained results can be summarized as follows. 1. Cuttings with dormant cutting stocs in the polyethylen house with heating and water mist spray resulting 100 percent survival. And temperature and the relative humidity in which fraim during the cutting season were around $20{\sim}25^{\circ}C$ and 70-90% respectively and in case as more significant other of the 1% Level. 2. With five varieties tested, resulting 93.8 percent survival, The F. value is not significant. 3. With four organs of cutting stock tested resulting 57.5 percent survival on the cuttings with two knodes of dormant cutting stock served as better cutting stock than others. The F. value is more significantly 1% Level. 4. Dormand bud served as possible cutting stock was found to be 17.66 survival percentage. 5. Both earlier and later stage of germinated Leaves with soft wood cutting stock poor cuttings, and the degree of development of 15th June cutting stock was optimum stage on the principal factor governing the success of cutting in the soft wood cutting showing 54% survival. The F. value is more 1% Level significant.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1991.11a
• /
• pp.54-58
• /
• 1991

It is well known that metal cutting leaves a plastically deformed layer in the machined surface. This residual phenomenon affects in various forms the physical properties of machined components such as the fatigue strength, the dimensional instability, microcracks, and the stress corrosion cracking. These physical properties, so called surface integrity, are very important for designing highly stressed and critically loaded components. Typical plastic strains in the machined surface are very difficult to measure, since they are located within a very short distance from the surface and they change very rapidly. There is an alternative way to determine the residual strain in plastically deformed materials by measuring the grain size after a subsequent recrystallization process. Although, this technique has been successfully applied by several researchers to find the plastic zone around notches and cracks in various materials and welding beads, few works have been reported using the recrystallization method to determine the residual strains in machined surface. Therefore, the purpose of this investigation Is to explore the effectiveness of the recrystallization technique in machining applications, and in particular, to find the effect of cutting parameters, i.e., depth of cut and rake angle on the plastic strains.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.4
• /
• pp.141-147
• /
• 1998

A plastically deformed layer in the precision machined surface affects in various forms the physical properties of machined components such as the fatigue strength, the dimensional instability, microcracks and the stress corrosion cracking. These physical properties, so called surface integrity, are very important for designing highly stressed and critically loaded components. Typical plastic strains in the precision machined surface are very difficult to measure, since they are located within a very short distance from the surface and they change very rapidly. A new way is suggested to determine the residual strain in plastically deformed materials by analyzing the plastically deformed layer after a subsequent recrystallization process. This investigation is to explore a new technique for measuring plastic strain in machining applications, and in particular, to and the effect of cutting parameters(rake angle, depth of cut, specific cutting energy), on the plastic strains and strain energy.

• Journal of Welding and Joining
• /
• v.21 no.5
• /
• pp.547-554
• /
• 2003

Apparent mechanical properties in structural components can be different from the initially designed values due to the formation of the residual stress in metal forming and welding. Therefore, the evaluation of residual stress has great importance in the reliability diagnosis of structural components. A nondestructive instrumented indentation technique has been proposed to evaluate various strength concerning mechanical properties from the analysis of load-depth curve. In this study, quantitative residual stress estimation on API X65 welded joints for natural gas pipeline was performed by analyzing the variation of indentation loading curve by residual stress through a new proposed theoretical model. The residual stress from the indentation method was compared with that from the saw-cutting method.

• Proceedings of the KWS Conference
• /
• 2003.11a
• /
• pp.103-105
• /
• 2003

Currently, duplex and superduplex stainless steels are widely used for piping system in offshore unit because of its excellent combination of strength and corrosion resistance properties. Also, the usage of duplex and superduplex stainless steel is steadily increasing with getting into step with development of offshore industries. In spite of excellent merits in mechanical and chemical properties of base materials, sometimes stringent requirements in welding procedure qualification and fabrication of duplex class material have regulated not only the application of various high-efficiency welding processes but also applicable welding parameters. This study is focused on hardness requirement which is known as one of the most stringent factor in duplex class material welding and this study aims to evaluate the effects of cutting and welding methodology on hardness values of duplex and superduplex stainless steel weldments.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2005.05a
• /
• pp.168-173
• /
• 2005

Composite material is combined with two or more chemical ingredient and different components. FRP has been widely used for the structure of aircraft, ships, automobiles, sporting goods and other machines because of their high specific strength, high specific stiffness and excellent fatigue strength. Recently, the development of machine tool and cutting tool greatly relies on high speed process to satisfy high precision, high efficient machining, shortened process time to maximize material removal rate (MRR) through high cutting speed and feed speed. The research molded CFRP, GFRP as stacking sequence methods of two direction (orientation angle $0^{\circ}\;and\;0^{\circ}/9^{\circ}$) hand lay-up, drilled molded plates using cemented carbide drill and examined chip shapes, surface roughness properties.

• Journal of the Korean Society of Industry Convergence
• /
• v.4 no.2
• /
• pp.185-191
• /
• 2001

Diphenylpropylamidophosphate(DPPAP) was synthesized as flame retardant for Expanded Polystyrene(EPS). Structure of DPPAP was investigated by the m, NMR, DSC. We make FR panels with EPS beads which treated with DPPAP and expanded by expand machines. FR panels were used in this study after formation by form machines and then cutting by cutting machines. The following conclusions were obtained: 1. The new synthetic agent was developed without the use of solvent such as pyridine or tertiary amine in the synthesis of DPPAP which served as flame retardant for EPS. 2. The flame retandancy effect of EPS treated with DPPAP was found excellent in LOI tests. 3. The properties of FR EPS panels treated with DPPAP did not difference.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.10
• /
• pp.170-179
• /
• 2000

The objective of this study is to develop an analytical module for the prediction of burr formation during cutting process using the finite element method. This module is based on the rigid-plastic finite element method, ductile fracture criterion, fracture propagation technique and node separation criterion. The sequence of burr formation from burr initiation through end of burr formation is simulated and investigated by this module. The effect of material properties, such as AL6061-T6, AL2024-T4 and Copper, and cutting condition, such as rake angle and cutting depth, on burr formation is also discussed in this study. To validate this module the analysis results are compared with experimental ones.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.9 no.4
• /
• pp.34-47
• /
• 2000

Since carbon fiber epoxy composite materials have excellent properties for structures due to their high specific strength, high specific modulus, high damping and low thermal expansion, the hollow shafts made of carbon fiber epoxy composites have been widely used for power transmission shafts for motor vehicles , spindles of machine tools, motor base, bearing mount for tool up and manufacturing. The molded composite machine elements are not usually accurate enough for mechanical machine elements, which require turning drilling , cutting and grinding. The experiment are surface grinding wheel GC60 to the carbon fiber epoxy composite specimen with respect to staking angle [0]nT , [45]nT, [90]nT on the CNC grinding machine. In this paper, the surface grinding characteristics of composite plate, which are surveyed experimentally and analytically with respect to the grinding force, surface roughness and wheel loading according to the variable depth of cut, wheel velocity and table feed rate are investigated.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.4
• /
• pp.119-126
• /
• 2007

Generally, the machinability of materials that have a good mechanical properties is poor. The material having a high strength, high toughness in high temperature and wear resistance, it is difficult to remove a chip from workpiece. STD11 and NAK80 are kinds of these materials and these materials can be used in many industrial fields. But it is limited in use because of high cost and poor machinability. In this experimental study, the cutting of STD11 and NAK80 were used to decide the machinability and the tool shape of CBN ball end mill. From the results, the CBN ball end mill is verified that the estimated cutting edge shape of rake angle 30 degree has consistent effect on the tool wear and cutting force.