• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.4
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• pp.107-114
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• 2006

Material selection is one of the important activities in design and manufacturing. A selected material at the conceptual design stage affects functionality of the designed part as well as manufacturability and cost of the final product. Unfortunately there are not many accessible material databases that can be used for design. In this research, a web-based material database was constructed. In order to assist designers to compare different materials, two-dimensional and three-dimensional graphs were provided via the web browser Using these graphical tools, multi-dimensional comparison was available in more intuitive manner. As a case study, this system was applied for material selection of an automotive engine pulley.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.484-486
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• 2004

In this paper, the power electronics requirement and the controls of an induction motor for fuel cell electric vehicle system are presented. The power topology is selected based on performance, cost, size, volume, manufacturability, component count and simplicity. Another highlight of the topology is the reduction of battery bank and its control strategy. The proposed approach consists a full-bridge DC/DC converter to boost the fuel cell voltage. The induction motor operated with vector control is driven by a three-phase PWM inverter supplied by the DC-link voltage. The investigation of the electric vehicle performed due to parameter variation of the induction motor has been presented.

• Korean Journal of Optics and Photonics
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• v.4 no.2
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• pp.145-156
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• 1993

From the optimal system specifications of optical parts in rear projection TV focused on competitive price and performances, we designed and developed projection lens which is able to be used on current broadcast standard NTSC and HDTV in common. Through the serial processes, which are initial design of all aberrations free, aspherization of the plastic lenses, optimization with tolerances and manufacturability, and athermalization, the lens was designed. The developed CRT-lens ass'y could display the 40-55 inches image and it's resolution is more than 1000 TV-lines.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.724-727
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• 2005

Material selection is one of the important activities in design and manufacturing. A selected material at the conceptual design stage affects material properties of the designed part as well as manufacturability and cost of the final product. Unfortunately there are not many accessible material databases that can be used for design. In this research, a web-based material database was constructed. In order to assist designers to compare different materials, two-dimensional and three-dimensional graphs were provided. Using these graphical tools, multi-dimensional comparison was available in more intuitive manner. To provide environmental safety of materials, the database included National Fire Protection Association publication Standard No.704. The web-based tool is available at http://fab.snu.ac.kr/matdb.

• IE interfaces
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• v.17 no.spc
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• pp.152-159
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• 2004

The Purpose of this paper is to propose performance evaluation schemes of flexible manufacturing cell using a generalized stochastic Petri net. In the competitive and global manufacturing environment, to evaluate the feasibility and manufacturability of a product in the product design stage is highly required. Through this process, all the possible problems which may occur in the manufacturing stage can be fixed in early stage. The scheme of generalized stochastic Petri net utilizing both immediate and exponential distributed transitions are applied to model a manufacturing cell with flexible machines, material handler, transporter and buffers. Performance analyses are performed based on behavioral, structural and quantitative properties. A flexible manufacturing cell is evaluated using a Petri net simulator.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.688-693
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• 2007

Most frame structures cannot be manufactured in a single-piece form. Ideally, when a structure is built up by assembling multi pieces, assembly at the joints should be rigidly performed enough to have almost full stiffness, which is difficult for practical reasons such as manufacturing cost and time. In this research, we aim to develop a manufacturability-oriented compliance-minimizing topology optimization using a ground beam model incorporating additional zero-length elastic joint elements. In the present formulation, design variables control the stiffness of zero-length elastic joints, not the stiffness of beams. Because joint stiffness values at the converged state can be utilized to select candidate assembly locations and their strengths, the technique is extremely useful to design multi-piece frame structures. An optimal layout is also extracted based on the stiffness values.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1237-1242
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• 2007

For the various RP processes and machines, quantitative comparisons were carried out, which include the variations of roughness according to inclined angle of surface, tensile strength and heat-resistance, shape accuracy affected by curl distortion, manufacturability of submilli-scale structure, and manufacturing speed. It was observed that steeper surface results in smoother roughness except Eden500V of Objet. Specimen made by LOM process showed the best heat-resistance, but that of SL process had heat-resistance only up to $60^{\circ}C$. Generally, tensile strength in the building direction was shown to be smaller than in the scanning direction, but SL process showed the opposite results. RM6000II of CMET was superior in the manufacturing small-scale structure below 0.2mm, and Z510 of Zcorp. and ViperPRO of 3D systems were great in manufacturing speed.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.572-577
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• 2007

The paper presents design optimization of an automobile body for dynamic stiffness improvement. The thicknesses of plates making-up the monocoque body of an automobile were employed as design variables for optimization and the objective was to increase the first torsional and bending natural frequencies. By allotting one design variable to each plate of the body, compared to previous works based on element-wise design variables, design space of optimization was reduced to a large extent and numerical instabilities such as checkerboard pattern was efficiently evaded. The method resulted to a considerable amount of increase in the automobile body's torsional and bending natural frequencies. Considering manufacturability of the optimized result, the converged values of plate thicknesses were approximated to commercially-available values by appropriately reflecting their design sensitivities.

• Journal of Pharmaceutical Investigation
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• v.35 no.4
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• pp.243-247
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• 2005

Although many scientists have used pectin, its feasibility in terms of tablet manufacturability with a high speed machine has never been evaluated. Therefore, compactibility of different pectin types for large scale tableting operation has been evaluated. The compactibility behavior of powder pectins was studied by a compaction simulator. It was found that pectin on its own does not produce tablets of acceptable quality even at a punch velocity as low as 20 rpm (e.g. low tensile strengths, capping and lamination irrespective of applied compression force). Thus, dwell time was introduced and more hard compact was produced as relaxation time in die increases. It was concluded that frequent structural failure observed in both pectin types was due to lack of plastic deformation, poor compactibility and high elastic recovery.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.206-209
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• 2002

With the progress of semiconductor processing technology, avalanohe photodiodes (APDs) based on InP/InGaAs are used for high-speed optical receiver modules. Planar-type APDs give higher reliability than mesa-type APDs. However, Planar-type APDs are struggled with a problem of intensed electric field at the junction curvature, which causes edge breakdown phenomena at the junction periphery. In this paper, we focused on studying the effects of junction curvature for APDs performances by different etching processes followed by single diffusion to from p-n junction. The performance of each process is characterized by observing electric field profiles and carrier generation rates. From the results, it can be understood to predict the optimum structure, which can minimize edge breakdown and improve the manufacturability.