• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.3 no.4
• /
• pp.280-284
• /
• 2002

This paper presents computer simulations of the stacking and transferring system for the fast freeform fabrication system. The stacking and transferring system is essential for the fast freeform fabrication system and its stable motion is very important for consistent stacking of the cut slices. The stacking and transferring system can be modeled as a pneumatic system. The system consists of air compressor, the control valve, and the cylinder. The governing parameters have been changed and the simulation results are shown to predict the time response of the system. The results show some parameters should be correctly tuned to obtain stable system response.

• The Transactions of the Korea Information Processing Society
• /
• v.5 no.1
• /
• pp.111-118
• /
• 1998

The density of fabric is a very important parameter in many fabric production processes. However, in the textile fabrication factories, textile density measurement process has been done inefficiently by handicraft. Thus, exact textile density measurement process is necessary to fabricate high quality textile through weft straighten. In this paper, we propose an automatic textile density measurement system to measure textile density automatically and to improve fabrication efficiency. The proposed system uses cylindrical lens to optically scan the weftl information of the fabric as well as convex lens to enlarge the weft images. The proposed system improves textile quality and provides constant density value to the whole textile range in the high speed fabrication process.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.12 no.1
• /
• pp.116-128
• /
• 2020

In the shipbuilding industry, three-dimensional (3D) templates play a key role in the completeness evaluation of shell plates with a large curvature in the shell-plate fabrication process. Currently, the information of 3D templates from a ship computer-aided design system is limited; thus, manufacturers depend on their experience to produce the templates manually. This results in the inaccuracy of templates in addition to increased production time. Therefore, if the pieces of the 3D templates can be produced automatically with accurate information, the lead time of the fabrication process can be reduced. In this study, we define a new type of template piece and develop methods for extending a boundary template and converting manufacturing information into numerical control machine input. In addition, based on the results of the study, we propose a production automation system for 3D template pieces. This system is expected to reduce the lead time of the fabrication process.

• IE interfaces
• /
• v.22 no.1
• /
• pp.73-84
• /
• 2009

In this paper, we propose a dispatching algorithm for constructing a Factory Operating System (FOS) which can operate semiconductor fabrication factories more efficiently and effectively. We first define ten dispatching criteria and propose two methods to apply the defined dispatching criteria sequentially and simultaneously (i.e. fixed dispatching architecture). However the fixed type methods cannot apply the criteria adaptively by considering changes in the semiconductor fabrication factories. To overcome this type of weakness, an adaptive dispatching architecture is proposed for applying the dispatching criteria dynamically based on the factory status. The status can be determined by combining evaluation results from the following three status criteria; target movement, workload balance, and utilization rate. Results from the shop floor in past few periods showed that the proposed methodology gives a good performance with respect to the productivity, workload balance, and machine utilization. We can expect that the proposed adaptive dispatching architecture will be used as a useful tool for operating semiconductor fabrication factories more efficiently and effectively.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.1003-1007
• /
• 2002

Micro-EDM is generally used far machining micro 3-D structure. For micro-EDM, first of all, micro-electrode fabrication is needed and WEDG system is proposed for tool electrode fabrication method. When tool electrode is fabricated using WEDG system, its characteristics are under the control of many EDM parameters. Also relations between the parameters affect electrode fabrication. In this study, experiments are carried out to analyze effects of EDM parameters on micro-electrode fabrication. Experimental method and analysis are used to experimental design method. Factors used in experiments are composed of applied voltage, capacitance, wire feed rate, spindle rotating speed, machining time. As a result of experiments, wire feed rate, machining time and capacitance is proportional to gap distance(material removal), the other parameters(applied voltage, spindle rotating speed) and relations between the parameters have little influence on machining.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.25 no.3
• /
• pp.443-451
• /
• 2001

This paper addresses an on-line scheduling method for track systems in semiconductor fabrication. A track system is a clustered equipment performing photolithography process in semiconductor fabrication. Trends toward high automation and flexibility in the track systems accelerate the necessity of the intelligent controller that can guarantee reliability and optimize productivity of the track systems. This paper proposes an-efficient on-line scheduling method that can avoid deadlock inherent to track systems and optimize the productivity. We employ two procedures for the on-line scheduling. First, we define potential deadlock set to apply deadlock avoidance policy efficiently. After introducing the potential deadlock set, we propose a deadlock avoidance policy using an on-line Gantt chart, which can generate optimal near-optimal schedule without deadlock. The proposed on-line scheduling method is shown to be efficient in handling deadlock inherent to the track systems through simulation.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.218-222
• /
• 2002

Micro-EDM is generally used far machining micro holes, pockets, and 3-D structures. For micro-EDM, first of all, micro-electrode fabrication is needed and WEDC system is proposed for tool electrode fabrication method. When tool electrode is fabricated using WEDG system, its characteristics are under the control of many EDM parameters. Also relations between the parameters affect electrode fabrication. In this study, experiments are carried out to analyze effects of EDM parameters about electrode surface integrity on micro-electrode fabrication. Experimental method and analysis are used to experimental design method. Factors used in experiments are composed of capacitance, resistance, pause time, wire feed rate, spindle rotating speed. As a result of experiments, capacitance and resistance affect electrode surface.

• Journal of the Korea Society of Computer and Information
• /
• v.12 no.4
• /
• pp.77-85
• /
• 2007

Asecure channel provides protection against interception, while an authentication system is created to protect the client and the server from fabrication attacks. This paper proposes a hybrid authentication algorithm, which fixes the lapses problem encountered in the SSL authentication. Also, the Proposed hybrid authentication system has been created to protect the client and the server from modification and fabrication attacks. By using a modified three-way authentication there is no need for a timeserver. thus timestamps are not needed.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.1394-1399
• /
• 2007

Recently, Study of 3D freeform fabrication method was working in the various applications. For example, in the powder base, it's laminated using a binding method or laser sintering method. However, these methods are not suitable in the office environments because it dust with powder that is bad for health. In this paper, we introduce a method of 3D freeform fabrication using a curing of photo-polymer resin and construct a system has multi printing head. A photo-polymer curing method has simply fabrication process and high strength of manufacturing part. However, this method has a problem on the multi print-head system. Because multi-printing system has a other printing method compare with a single printing system. Therefore, we experiment a single head 3D printing and proposed a 3D printing method using a multi-piezo head.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.91.1-91
• /
• 2002

1. Introduction Present study presents the basic concept of a Solid Freeform Fabrication System using a rapid prototyping procedure and optimal control for a transferring and accumulating system. And it developed a novel rapid prototyping process that can use ceramic or metal as well as polymer as a basic material. 2. Solid Freeform Fabrication System 2.1 Basic Theory A 3D CAD data of the model is converted to the 2D cross-section data of the slides. A ceramic or metal tape of thickness 0.5-1.5mm is cut by a laser beam with the cross-section data of the slide. A 3D model was obtained by transferring and accumulating the slides. The final product is manufactured by sin...