• International Journal of Precision Engineering and Manufacturing
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• 제6권1호
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• pp.15-22
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• 2005

This research presents modeling of a functional surface that is constructed with a free-formed surface. The modeling of functional surfaces, being introduced in this paper, adopts a modified B-spline that utilizes an approximating technique. The modified B-Spline is constructed with altered control vertices. It is applied to measure the surface of an impeller blade. This research builds an algorithm accepting inputs of measured points. Generating the cutter-paths for NC machining employs the model of the constructed surfaces. The machined surfaces that are generated in several cases are compared with each other in the aspect of machining accuracy.

• 대한기계학회논문집A
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• 제31권1호
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• pp.105-112
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• 2007

The linkage framework of geometric modeling based on NURBS(Non-Uniform Rational B-Spline) surface and shell finite analysis is developed in the present study. For this purpose, geometrically exact shell finite element is implemented. NURBS technology is employed to obtain the exact geometric quantities for the analysis. Especially, because NURBS is the most powerful and wide-spread method to represent general surfaces in the field of computer graphics and CAD(Computer Aided Design) industry, the direct computation of surface geometric quantities from the NURBS surface equation without approximation shows great potential for the integration between geometrically exact shell finite element and geometric modeling in the CAD systems. Some numerical examples are given to verify the performance and accuracy of the developed linkage framework. In additions, trimmed surfaces with some cutouts are considered for more practical applications.

• International Journal of CAD/CAM
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• 제3권1_2호
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• pp.1-12
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• 2003

When milling concave corners, cutter load increases momentarily and fluctuates severely due to concentration and uneven distribution of material stock. This abrupt change of cutter load produces undesirable machining results such as wavy machined surface and cutter breakage. An important factor for studying cutter load in 2.5D pocket milling is the instantaneous Radial Depth of Cut (RDC). However, previous work on RDC under different corner-cutting conditions is lacking. In this different corner shapes. In our work, we express RDC mathematically in terms of the instantaneous cutter engage angle which is defined as Cutter Swept Angle (CSA). An analytical approach for modeling CSA is explained. Finally, examples are shown to demonstrate that the proposed CSA modeling method can give an accurate prediction of cutter load pattern at cornering cut.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.864-865
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• 2008

This paper deals with d-q axis inductance measurements of IPMSM considering core loss at low speed. d-q axis inductance measurements generally are conducted at rated speed and parallel core loss model can be used to exclude core loss effects on inductances. Core loss is generally modeled parallel to input terminal of d-q axis equivalent circuit. Therefore, the effect of core loss on inductance calculation can be varied by core loss modeling. In this paper, d-q axis inductance is calculated parallel and series core loss modeling. Calculated inductances are compared to FEA results and it is concluded that series core loss modeling is more closed to FEA results at low speed.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.452-459
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• 2015

Thanks to the development of applications, many people are using a smart phone cradle these days. But it has some problems. First of all, it is hard to fix on automobiles. Also, it is vulnerable to external vibration. Recognizing these problems, we decided to improve this device by using FreeCAD and ANSYS. Because FreeCAD is newly invented software, we used another 3D modeling software to cover shortages of tools in FreeCAD. Also, we used famous analysis software 'ANSYS' to analyze bending deformation, modal analysis, and harmonic analysis.

• 마이크로전자및패키징학회지
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• 제20권3호
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• pp.7-10
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• 2013

This study presents an approach to predict insulation resistance failure of multilayer ceramic capacitors (MLCCs) using non-linear modeling. A capacitance aging model created by non-linear modeling allowed for the prediction of insulation resistance failure. The MLCC data tested under temperature-humidity-bias testing conditions showed that a change in capacitance, when measured against a capacitance aging model, was able to provide a prediction of insulation resistance failure.

• 산업공학
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• 제16권spc호
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• pp.138-143
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• 2003

In this paper, an automated design system for ball-joint parts based on 3-D solid modeler is developed. Parametric modeling and API provided by 3-D solid modeler is engaged to develope the system which consists of four main modules such as : 3-D part modeling, parts assembling, 2-D drafting, and database interfacing modules. The automated design system is implemented on a computer, and shows us that it shorten the design processing time which have taken over 5 hours to only few minutes.

• International Journal of CAD/CAM
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• 제7권1호
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• pp.81-89
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• 2007

As the modular production is an important issue in globalized manufacturing industries, sub modules or parts of the final product are provided by many suppliers. Some part suppliers design their own products for themselves. In some cases, part supplier may provide the same type product to multiple 1-tier companies. Because all suppliers and 1-tier companies can not use the same CAD system in general case, the engineering change in the CAD model of one company could not propagate to related CAD models of other companies directly. Although they use the same CAD system, it is hard to share their CAD model with each other because of company security policy. In this paper, the neutral reference model, which consists of the neutral skeleton model and the external reference model, is proposed to apply a global top-down modeling approach to collaborating companies.

• 설비공학논문집
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• 제25권1호
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• pp.20-27
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• 2013

Numerical modeling of $CO_2$ water heater was conducted prior to optimal design of medium and large sized $CO_2$ water heater, and the experimental test with small sized $CO_2$ water heater having heat capacity of 4 kW was completed to verify the present numerical model. The present model estimated the experimental data of COP(coefficient of performance), heating capacity, and the hot water outlet temperature within the range of 3% to 8% of mean deviation. As increase of EEV(electric expansion valve) opening area, decreasing of heating capacity and the hot water outlet temperature, and increasing of COP were found in both experimental and numerical investigation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.747-753
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• 2001

This paper presents a dynamic modeling and a robust PID controller design process for the wire bonder head assembly. For the modeling elements, the system is divided into electrical system, magnetic system, and mechanical system. Each system is modeled by using the bond graph method. The PID controller is used for high speed/high accuracy position control of the wire bonder assembly. The Taguchi method is used to evaluate the more robust PID gain combinations. This study makes use of an L18 array with three parameters varied on three levels. Computer simulations and experimental results show that the designed PID controller provides more improved signal to noise ratio and reduced sensitivity than the conventional PID controller.