• Proceedings of the KWS Conference
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• 2001.05a
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• pp.114-116
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• 2001

This study deals with friction stir welding of aluminum alloy(A5083). Welding conditions were applied that revolution 2000rpm, friction pressure 25MPa, angle between stir rod section and plate 4$^{\circ}$, projection pin diameter 4mm, traverse speed 0.5mm/sec, 1.0mm/sec, 1.5mm/sec. The experimental results as follows; 1. Welding beads were superior in traverse speed 1.0mm/sec and it were formed plenty of flash in traverse speed 0.5 mm/sec. Welding beads were rough in traverse speed 1.5mm/sec. 2. The maximum tensile strength was 211MPa in traverse speed 1.0mm/sec, in this case the strength was 85% of A5083 base metal tensile strength.

• Journal of the Korean Society for Heat Treatment
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• v.5 no.2
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• pp.122-132
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• 1992

This study has been performed to investigate into some effects of the power density and traverse speed of laser beam on the optical microstructure, hardness and wear characteristics of medium carbon low alloy steel treated by laser surface hardening technique. The results obtained from the experiment are summarized as follows : (1) Optical micrograph has shown that finer lath martensite is formed and the amount of undissolved complex carbides increases as the traverse speed increases under the condition of a given power density, whereas the coarsening of lath martensite and the reduction of undissolved complex carbides occur with increasing the power density at a given traverse speed. (2) Hardness measurements have revealed that as the traverse speed increases, hardness values of outermost surface layer more of less decrease under low power densities, but are uniformly distributed under high power densities, also showing that they are uniformly distributed at low traverse speeds and more or less decrease at high traverse speeds with increasing the power density. (3) The effective case depth has been found to decrease from 0.26 mm to 0.17 mm with increasing the traverse speed from 1.5 m/min to 3.0 m/min at a given power density of $25.48{\times}10^3w/cm^2$ and to increase from 0.20 mm to 0.36 mm with increasing the power density from $19.11{\times}10^3w/cm^2$ to $38.22{\times}10^3w/cm^2$ at a given traverse speed of 2.0 m/min. (4) Wear test has exhibited that the amount of weight loss of laser surface hardened specimen with respect to sliding distance at a given load increases with increasing traverse speed at a given power density and decreses with increasing power density at a given traverse speed.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.7
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• pp.61-68
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• 1998

The form accuracy of parts has become an important parameter. Therefore, dimensional tolerance and geometric tolerance are used in the design stage to satisfy required quality and functions of parts. But the informations on the machining conditions, which can satisfy the assigned geometric tolerance in design, are insufficient. The objectives of this research are to study the effects of the grinding parameters such as traverse speed, work speed, depth of cut, and dwell time on the after-ground workpiece shape, and to find out the major parameters among them. The results are as follows, The effects of work speed and depth of cut on workpiece shape are negligible compared with the effect of traverse speed. There is an optimal dwell time depending on the traverse speed. The optimal dwell time is decreasing as the traverse speed is increased.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.3
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• pp.55-61
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• 2003

The form accuracy of parts has become an important parameter. Therefore, not only dimensional tolerance but also geometric tolerances are used in the design stage to satisfy the required quality and functions of parts. But the information on the machining conditions, which can satisfy the assigned geometric tolerance in do sign, is insufficient. The objectives of this research are to study the effects of the grinding parameters such as traverse speed, work speed, depth of cut, and dwell time on the after-ground workpiece shape, and to find out the major parameters among them The results are as follows; The effects of work speed and depth of cut on the workpiece shape are negligible compared with the effect of traverse speed. These is an optimal dwell time depending on the traverse speed. The optimal dwell time is decreasing as the traverse speed is increasing.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.95-99
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• 1996

The form accuracy of parts has become an important parameter. Therefore dimensional tolerance and geometric tolerance are used in design to satisfy required quility and functions of parts. But the informations for machining conditions, which can satisfy the assigned geometric tolerance in design, are insufficient. The objectives of this research are to study the effects of the grinding parameters such as traverse speed, work speed, depth of cut, and dwell time on the after-ground workpiece shape, and to find out the major parameters among these parameters. Finally, a methodology is proposed for getting the optimal grinding condition for precision workpiece The results are as follows; The effects of work speed and depth of cut on workpiece shape are ignorable compared to the effect of traverse speed. These is the optimal dwell time depending on the traverse speed. The optimal dwell time is decreasing when the traverse speed is increased.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.413-418
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• 1996

Alternate pirn winding is more difficult to control than others because starting points of its traverse strokes are changed alternately through the winding operations. However, the alternate pirn winding is ye useful method because the yarn can be hardly broken when it is unwinded from full packaged bobbin. This paper presents kinematic control algorithm for the alternate pirn. The proposed algorithm can decide the values of control variables such as bobbin speed and traverse speed from the given input parameters and constraints by using the kinematic relations of the winding mechanism. The compute simulations and experimental verifications of the developed winding control algorithm are carried out It is concluded that the proposed algorithm is an efficient and reliable alternative to traditional trial and error control methods.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.133-139
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• 2003

Direct motor-driven winding has been increasingly applied in winding machinery. However, it is necessary to analyze the kinematics of winding prior to developing the winding control algorithm, because direct motor-driven winding machine should be operated in accordance with the pre-determined kinematic information for the winding control. This paper presents the kinematics of the degressive winding method and its kinematic winding control algorithm in order to wind the required volume of a pirn package in a desired shape. The proposed algorithm can give the appropriate yarn speed, traverse speed, and the spin speed of the spindle at every traverse stroke, which are utilized for controlling the spindle motor and traverse motor of the winding machine. Computer winding simulations showed that the proposed algorithm is successful in the degressive pirn winding.

• Laser Solutions
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• v.2 no.2
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• pp.42-51
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• 1999

This study has been performed to investigate into some effects of the output power and traverse speed of laser beam on the microstructures, hardness and fatigue resistance of the ductile iron surface-hardened by $CO_2$ laser defocussed beam. Optical micrographs have shown that with increasing the output power and decreasing the traverse speed, the martensite was coarsened and some retained austenite were appeared in ductile iron. The microstructures of hardening zone were composed of bull's eye and some nodular graphite dissolved structures by the effect of self quenching. Fatigue fracture characteristics of ductile iron have appeared in the high stress and low stress ranges. The fracture initiated at nodular graphites in the surface hardened layer due to the stress concentration caused by a notch effect. The interior graphite nodules were broken away or popped out during crack propagation. Fatigue test has shown that values of fatigue strength considerably increased with increasing output power at a given traverse speed.

• Journal of Power System Engineering
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• v.15 no.2
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• pp.61-68
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• 2011

This paper investigates the tensile properties of the friction stir welded joints of Al 7075-T651 aluminum plate according to the welding conditions. A 7075-T651 aluminum alloy plate with a thickness of 6.0 mm was used in this investigation. For the friction stir welding (FSW) process, a tool with shoulder diameter of 20 mm and probe diameter of 9 mm was used. The rotation speed and traverse speed conditions were changed in this study, the other welding conditions are constant. The welding direction was aligned with the material rolling direction, and dimension of the FSW plate were $250{\times}100{\times}6\;mm$. As far as this work is concerned, the optimal FSW conditions are determined as the rotation speed, 600 rpm and traverse speed 0.8 mm/sec or the rotation speed, 800 rpm and traverse speed 0.5 mm/sec.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.7
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• pp.693-699
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• 2009

This paper shows mechanical properties and behaviors of macro- and micro-structures on friction stir welded specimen with 6061-T6 aluminum alloy plate. It apparently results in defect-free weld zone jointed at welding conditions like the traverse speed of 267mm/min, tool rotation speed of 2500rpm, pin inserted depth of 4.5mm and tilting angle of $2^{\circ}$ with tool dimensions such as tool pin diameter of 5mm, shoulder diameter of 15mm and pin length of 4.5mm. The tensile stress ${\sigma}_T=228MPa$ and the yield point ${\sigma}Y=141MPa$ are obtained at the condition of traverse speed of 267mm/min and tool rotation speed of 2500rpm. With the constant rotation speed, the higher traverse speed become, the higher tensile stress and yielding point become. Vickers hardness for welding zone profile were also presented.