• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.105-110
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• 1999

Wire electrical discharge machining (WEDM) is one of the unconventional machining processes, which is utilizing electrical energy to remove work-piece. In recent years WEDM used widely in die-sinking industry because WEDM can machine any hard materials if only it has conductivity and can machine accurately to the complex geometry, for fine wire is used in WEDM for the tool electrode. However WEDM is non-contact machining process, which is utilizing discharge phenomena occurring between two electrodes, the size of the machined part is larger than that of the tool electrode size. It is called discharge gap or clearance the difference size between the tool electrode and the machined part in WEDM. By the experiment clearances according to the machining condition was investigated.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.5
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• pp.155-160
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• 2018

The materials used for 3D printing are mainly plastic and metal. These materials are usually used in the powdered form. In order to improve the surface roughness of a manufactured product, these powders should consist of small uniform spherical particles. However, the powdered forms are sold at a considerably higher price than bulk or wired materials. When a wire-type material is used instead of a powder, we can supply a relatively large amount of the material at one time as well as reduce the cost. Moreover, the use of this form of the material will increase the process efficiency. This paper deals with the technology required to feed a wire material in front of the tool movement and discusses the examples used for the verification.

• The korean journal of orthodontics
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• v.44 no.5
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• pp.236-245
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• 2014

Objective: To evaluate the therapeutic effects of a preformed assembly of nickel-titanium (NiTi) and stainless steel (SS) archwires (preformed C-wire) combined with temporary skeletal anchorage devices (TSADs) as the sole source of anchorage and to compare these effects with those of a SS version of C-wire (conventional C-wire) for en-masse retraction. Methods: Thirty-one adult female patients with skeletal Class I or II dentoalveolar protrusion, mild-to-moderate anterior crowding (3.0-6.0 mm), and stable Class I posterior occlusion were divided into conventional (n = 15) and preformed (n = 16) C-wire groups. All subjects underwent first premolar extractions and en-masse retraction with preadjusted edgewise anterior brackets, the assigned C-wire, and maxillary C-tubes or C-implants; bonded mesh-tube appliances were used in the mandibular dentition. Differences in pretreatment and post-retraction measurements of skeletal, dental, and soft-tissue cephalometric variables were statistically analyzed. Results: Both groups showed full retraction of the maxillary anterior teeth by controlled tipping and space closure without altered posterior occlusion. However, the preformed C-wire group had a shorter retraction period (by 3.2 months). Furthermore, the maxillary molars in this group showed no significant mesialization, mesial tipping, or extrusion; some mesialization and mesial tipping occurred in the conventional C-wire group. Conclusions: Preformed C-wires combined with maxillary TSADs enable simultaneous leveling and space closure from the beginning of the treatment without maxillary posterior bonding. This allows for faster treatment of dentoalveolar protrusion without unwanted side effects, when compared with conventional C-wire, evidencing its clinical expediency.

• The korean journal of orthodontics
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• v.42 no.1
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• pp.39-46
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• 2012

Objective: We evaluated the detachment force, amount of deformation, fracture mode, and pull-out force of 3 different wires used for bonded lingual retainer fabrication. Methods: We tested 0.0215-inch five-stranded wire (PentaOne, Masel; group I), $0.016{\times}0.022$-inch dead-soft eight-braided wire (Bond-A-Braid, Reliance; group II), and 0.0195-inch dead-soft coaxial wire (Respond, Ormco; group III). To test detachment force, deformation, and fracture mode, we embedded 94 lower incisor teeth in acrylic blocks in pairs. Retainer wires were bonded to the teeth and vertically directed force was applied to the wire. To test pull-out force, wires were embedded in composite that was placed in a hole at the center of an acrylic block. Tensile force was applied along the long axis of the wire. Results: Detachment force and mode of fracture were not different between groups. Deformation was significantly higher in groups II and III than in group I (p < 0.001). Mean pull-out force was significantly higher for group I compared to groups II and III (p < 0.001). Conclusions: Detachment force and fracture mode were similar for all wires, but greater deformations were seen in dead-soft wires. Wire pull-out force was significantly higher for five-stranded coaxial wire than for the other wires tested. Five-stranded coaxial wires are suggested for use in bonded lingual retainers.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.503-508
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• 2002

In this study, the relation between the mtation which are usually caused by the creep of the contact wire, the bar geometry and the forces(wire tensions) for the triangle-shaped distribution bar and straight-shaped one in dependent tensioning device system is reviewed. According to the result a rotation of distribution bar in triangle-shaped one modifies the distribution of the tensions between the three wires hooked in a distribution bar. On the contrary, a rotation on the straight-shaped one leads to no tension distribution change. Therefore, to use the straight-shaped distribution bar instead of triangle-shaped one is recommended. In addition, the design contents of the distribution bar which will be used in electrification of Gyeongbu line are described in this paper.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.823-832
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• 1996

The purpose of this study was to assess the effect of 1) the diameter(0.7,1.0,1.2mm) and number(1,2,3) of commonly available orthodontic metal wires embedded in self-curing orthodontic acrylic resin specimens($64{\times}10{\times}3mm$) and 2) the use of chemical adhesive system(Silicoater, Metalprimer) to prevent slipping at the interface between the resin and the metal wire on reinforcement by using three-point bending test. From this study, the following results were obtained. 1. No statistically significant difference was found among the transverse strengths for the control without reinforcement, one 0.7mm wire, two 0.7mm wires, three 0.7mm wires, and one 1.0mm wire groups(P>.05). 2. In the groups with 1.0 or 1.2mm wires, the transverse strength increased in proportion to the increase of number of wires(P<.05). 3. In the groups with 0.7 or 1.0mm wires, neither of Silicoater and Netalprimer increased the transverse strength significantly(P>.05). 4. No statistically significant difference was found in transverse strength between Silicoater groups and Metalprimer groups with same diameter of wires(P.>05). From these result, it is concluded that diameter of wires is a primary considering factor to reinforce the acrylic resin effectively and, when this requirement is satisfied, increased number of wires or chemical adhesive systems can be expected to produce the additional reinforcing effect.

• Korean Journal of Computational Design and Engineering
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• v.1 no.1
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• pp.33-44
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• 1996

This study deals with the development of wire path searching module as a part of automobile wire harness design system. Wire path searching module manages the free space, finds transition locations, and creates bundle paths to dramatically reduce a tedious iterative routing process which results in easy optimization of the bundle paths. A prime policy in the system configuration is to compromise between man's and computer's ability, and make it possible a designer's leading role in designing process. Human input is indispensable to cope with the special cases which were not considered in the initial design stage of the system. In this study, we improve the previous shortest-path-finding algorithm, (VGraph and RCA method) into a new method called Extended RCA. Bundles, connectors and transitions are handled as objects so one can manage and modify physical properties of the objects easily. Therefore a verification is allowed at any desired stage of design. The reuse of previous result is facilitated by using Dependency Structure, which represents the mutual relations among connectors, transitions, and bundles. Dependency Structure makes it possible the elimination of redundant calculating process, and consequently shorter routing time.

• Journal of environmental and Sanitary engineering
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• v.14 no.3
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• pp.116-122
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• 1999

The purpose of this study is to develop new process named "hydrogen peroxide dissolution method". This process used hydrogen peroxide, which is harmless to human body and oxidize molybdenum wire selectively.The advantages of hydrogen peroxide dissolution method were no discharge of noxious matter when dissolution of molybdenum wire which used as the center supporter, reactions occur in room temperature and easy to recover dissolved molybdenum. This study was aimed at gathering the basic data of molybdenum wire dissolution-recovery process and proposes the reaction condition of molybdenum wire dissolution-recovery process and the factors influencing those reactions. The results were as follows:1. In the dissolution of molybdenum wire, the early condition of reaction was $15^{\circ}C$, and the temperature condition of state was $32^{\circ}C$. 2. 1) In the GSL-60W type, P.W.(Piece weight) was 11.89mg, C.R. was $65.6\Omega$. 2) In the FL-20W type, P.W. was 11.60mg, C.R. was $4.6\Omega$. 3. The molybdenum of process water was treated of a precipitation after dry and after stagnation in the one day, the molybdenum of upper water was treated of precipitation after dry and after congelation.

• Journal of the korean Society of Automotive Engineers
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• v.13 no.4
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• pp.62-75
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• 1991

The purpose of this study is to perform modelings and experiments to measure air flow rate using hot-wires and a CTA(Constant Temperature Anemometer). The flow rate can be obtained by measuring the heat loss of the hot-wire due to the variations of flow velocity when the hot-wire is maintained at uniform temperature. But the defect of this method is that the output signal changes not only by the flow rate but also by the ambient temperature. Thus, in the present study, a method which compensates the variations of the ambient temperature has been introduced to measure exact flow rate. To be more specific, the bridge circuit of the usual hot-wire anemometer system has been modified in such a way that a temperature resistance sensor and a variable resistance are placed in one of the legs to compensate the different temperature coefficients of both the hot-wire and the temperature compensating resistance for flow velocity or for flow mass up to the flow temperature of 50 .deg.C. Comparing the modeling and experimental results, it has been shown that the compensating point differs as the flow rate varies. Therefore, optimum compensation points are sought to construct the circuit. The present modeling and experimental results may be applied to the design of actual air flow meters for automobiles.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.119-125
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• 1999

At Wire Rod Mill Plant, wire is made of the billet produced at continuous casting machine, or rolled bloom produced at billeting mill, and the product can be classified of wire of 5.5${\Phi}$ and bar in coil of 14∼42${\Phi}$ in diameter(bar in coil will be referred to as coil as below). At present, wire is produced at POSCO No.1, 2, 3 WRM, coil at garret line of No. 2 WRM. Head and tail of coil are properly cut and treated to scrap to fulfill the customer's satisfaction. This above cutting is done off line, and small size coil can be cut manually with clipper, large size coil with hydraulic cutter. Nowadays, it is being investigated to cut automatically in line with trimming shear after passing mill stand. At the moment, Because the coil produced at the garret line of No.2 WRM is hot 400∼600$^{\circ}C$ and trimming is done manually with cutter, there are always interference from manual operation or safety problem of bad working condition. Not only because of the diversity of the coil size 14∼42${\Phi}$ in diameter, but because of the rolling speed 2.5∼22m/sec, it is required to be equipped with several trimming shear. But this can be accomplished with only one shear installed proper place at this paper.