• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.487-488
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• 2006

As DLC coating possesses such features as, high hardness, high elasticity, abrasion resistance and chemical stability, there have been exerted continuous efforts in research works in a variety of fields, and this technology has also been applied widely to industrial areas. In this research work, the optimal grinding condition was identified using Microlens Process Machine in order to contribute to the development of aspheric glass which is to be used for mobile phone module having 2 megapixel and $2.5{\times}$ zoom, and mold core (WC) was manufactured having performed ultra-precision machining and effects of DLC coating on shape accuracy(P-V) of mold core and surface roughness(Ra) as well were measured and evaluated.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.3
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• pp.81-87
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• 2009

Lightweight board has been used for manufacturing various fields of automotive interior trims for years. The GMPU board was constructed with glass fiber mat, honeycomb and polyurethane foamed using polyol and isocyanate materials which were sprayed by robot that is interlocked foaming machine. For more lightweight and cost reduction this paper shows how to optimize GMPU process parameters that related to foaming condition, robot position and robot velocity for polyurethane weight. The results show that flexural strength and modulus of board's specimens were evaluated by robot velocity and moving pattern. Based on that, a innovative process was developed for more lightweight and cost reduction.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.85-88
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• 2003

In case that any jobs in a Job Shop can be scheduled on more than one machine and may have flexible operation sequences, with considering such case it is very difficult and complex to make the optimal process plans and scheduling. But they should be considered for an integrated model to perform more effective process planning and scheduling in this job shop problem. In this paper, we propose GA-based scheduling method to integrate effectively the problem of alternative machines, alternative operation sequences and scheduling. The performance of proposed GA is evaluated through comparing integrated scheduling with not integrated scheduling in molding company with alternative machines and operation sequences. Also, we use benchmark problems to evaluate performance. The scheduling method in this research will apply usefully to real world scheduling problems.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.1
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• pp.35-41
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• 2003

In this paper, a machine vision system for recognizing and classifying the patterns and marks engraved by die molding or laser marking on the glass panels of computer monitors is suggested and evaluated experimentally. The vision system is equipped with a neural network and an NGC pattern classifier including searching process based on normalized grayscale correlation and adaptive binarization. This system is found to be applicable even to the cases in which the segmentation of the pattern area from the background using ordinary blob coloring technique is quite difficult. The inspection process is accomplished by the use of the NGC hypothesis and ANN verification. The proposed pattern recognition system is composed of three parts: NGC matching process and the preprocessing unit for acquiring the best quality of binary image data, a neural network-based recognition algorithm, and the learning algorithm for the neural network. Another contribution of this paper is the method of generating the training patterns from only a few typical product samples in place of real images of all types of good products.

• Tribology and Lubricants
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• v.5 no.2
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• pp.94-100
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• 1989

Friction and Wear behavior of continuous graphite fiber composites was studied for different fiber orientations against the sliding direction. The effect of fiber orientation on friction and wear of the composite and on the deformation of the counterface was investigated experimentally. Pin on disk type testing machine was built and employed to generate the friction and wear data. A graphite fiber composite plate was produced by the bleeder ply molding in an autoclave and machined into rectangular pin specimens with specific fiber orientations, i.e., normal, transverse, and longitudinal directions. Three different wear conditions were employed for two different periods of time, 24 and 48 hours. The wear track of the worn specimens and the metal counterface was examined with a scanning electron microscope (SEM) to observe the damaged fibers on the surface and wear film generation on the counterface. Wear mechanism of the composite during sliding wear is proposed based on the experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.99.2-99
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• 2002

Contents 1 In this paper a machine vision system for recognizing and classifying the patterns and marks engraved by die molding or laser marking on glass panel of computer monitor is suggested and evaluated experimentally. The vision system is equipped with a neural network based pattern classifier and searching process based on normalized grayscale correlation and adaptive binarization, which is applicable to the cases in which the segmentation of the pattern area from background using the ordinary blob coloring technique is quite difficult. Inspection process is accomplished via the way of NGC hypothesis and ANN verification. The proposed pattern recognition system is composed of three...

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.71-74
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• 2003

The cell modeling homogenization method to derive the constitutive equation considering the microstructures of the fiber reinforced composites has been previously developed for composites with simple microstructures such as 2D plane composites and 3D rectangular shaped composites. Here, the method has been further extended for 3D circular braided composites, utilizing B-spline curves to properly describe the more complex geometry of 3D braided composites. For verification purposes, the method has been applied for orthotropic elastic properties of the 3D circular braided glass fiber reinforced composite, in particular for the tensile property. Prepregs of the specimen have been fabricated using the 3D braiding machine through RTM (resin transfer molding) with epoxy as a matrix. Experimentally measured uniaxial tensile properties agreed well with predicted values obtained fer two volume fractions.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.428-432
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• 2003

The technical combination of RP and RT has a potential for rapid manufacturing of three-dimensional parts. In the present work a new RP system, $VLM-_{ST}$, is proposed to manufacture net shapes of 3D prototypes. ㅁ human head shape and a kob shape are manufactured by the $VLM-_{ST}$ apparatus. In addition, a new RT technology, which utilizes a RTV molding technique and a triple reverse process technique, is proposed to manufacture net shapes of 3D plastic parts using prototypes of $VLM-_{ST}$. A plastic part of the knob shape os produced by the proposed RT technology. The combination of the proposed RP and RT enables the manufacturing of a plastic knob within two days.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.28-34
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• 2008

Mg alloy is widely used for the IT, auto and consumer electronics industries. Semi-solid casting(SSC) of magnesium alloys is used to produce high quality components. SSC process is analogous with the injection molding of plastics. The high strength and low weight characteristics of magnesium alloys render the high-precision fabrication of thin-walled components with large surface areas. To produce thin-walled magnesium alloy parts, SSC process parameters on the quality of the finished product should be clearly studied. In this paper, to select optimal process parameters, Taguchi method is applied to the optimal design of the process parameters in the SSC process. The die temperature, injection velocity and barrel temperature of the SSC process are selected for the process parameters. The effectiveness of the optimal design is verified through the CAE software.

• Composites Research
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• v.13 no.5
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• pp.44-49
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• 2000

Although the net-shape molding of composites is generally recommended, molded composites frequently requires cutting or grinding due to the dimensional inaccuracy for precision machine elements. The surface roughness and cutting force were also measured to investigate the surface grinding characteristics of the composites using the vitrified bonded wheel (WA, GC). The experiments were performed dry grinding conditions with respect to cutting speed, feed speed, depth of cut of the stacking sequence $[O]_{nT.}$ From the experimental investigation, the optimal conditions both the vitrified bonded wheel WA and GC for the surface grinding are suggested.