• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.1
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• pp.120-130
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• 1994

The leadwire cutting machine that has been used recently cuts leadwires by putting one-side force with the same priciple as a saw, and applies a stress at soldered part of PCB. Because the stress becomes one cause of contact-defect, a leadwire cutting robot that cuts leadwire-site with nipper and does not apply stress is considered, In this paper a technique of detecting leadwire-site is studied for the purpose of using on automatic leadwire cutting robots. A technique deriving 2-dimensional site-information with many I-dimensional binary data of perspective front-view of PCB taken from various direction was proposed. Simulation and experiments were done under the same condition each other and a small universal PCB was choosen as an experimental object. As a result of simulations and experiments, the proposed technique turns out to be very useful for automatic leadwire cutting robots.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.319-320
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.713-714
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• 2008

• CDE review
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• v.3 no.3
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• pp.64-65
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• 1997

이 글에서는 1. NC 프로그램의 역사 2. NC 프로그래밍의 주요 문제 - 2차원 형상의 가공, 3차원 곡면 가공, 공구 및 holder와 공작물, 치공구와의 간섭 및 충돌 방지, 5축 및 다축 NC 가공, NC 가공을 위한 곡면 모델, 가공경로 검증 및 Cutting simulation, 곡면 또는 pocket 가공에서 공구의 자동 선정 등에 대하여 다루었다.

• Journal of Information Processing Systems
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• v.8 no.1
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• pp.101-118
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• 2012

Embedded products are becoming richer in features. Simulation tools facilitate low-costs and the efficient development of embedded systems. SID is an open source simulation software that includes a library of components for modeling hardware and software components. SID components were originally written using C/C++ and Tcl/Tk. Tcl/Tk has mainly been used for GUI simulation in the SID system. However, Tcl/Tk components are hampered by low performance, and GUI development using Tcl/Tk also has poor flexibility. Therefore, it would be desirable to use a more advanced programming language, such as Java, to provide simulations of cutting-edge products with rich graphics. Here, we describe the development of the Java Bridge Module as a middleware that will enable the use of Java Components in SID. We also extended the low-level SID API to Java. In addition, we have added classes that contain default implementations of the API. These classes are intended to ensure the compatibility and simplicity of SID components in Java.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.154-162
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• 1991

In this study, the simulation program is developed where the tooth profile error in internal gear shaping is calculated considering several factors which affect it. This factors are the circular feed of the pinion cutter, the interference by the geometric conditions of the cutter and the internal gear, the deviation from the theoretical involute profile of the cutter and the eccentricity of the cutter and the internal gear. With this program, the effects are investigated which the geometric conditions and the cutting conditions in internal gear shaping have on the tooth profile error of the internal gear. The condition for the minimization of it is derived and then the results of simulation are adequately verified by measurements of internal gears cut by a pinion cutter.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.215-219
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• 2001

The resonators made of piezoelectric crystals such as a quartz crystal are widely used. Their frequency-temperature characteristics are of primary importance for their applications to the frequency control devices. The characteristics estimation is useful for determining their design parameters. In the present paper, several types of resonators are numerically analyzed. The numerical solutions are made using 3-D Finite Element Modeling, and the results are compared with the theoretical values whenever they are available. To demonstrate the validity of the present numerical approach, the application is made to the analysis of the plates with some well-established cutting angles. For the resonator stable with temperature change, the cutting angle is important in which the temperature coefficient of the first order is chosen to be zero. The rotated Y-cut plates in thickness-shear mode are considered. The equivalent circuit representation is often used fur describing the characteristics at the electrical terminals which enables the circuit analysis including the effect of temperature change by using the circuit simulators. The equivalent circuit parameters are obtained by fitting the admittance-frequency curve from the finite element analysis.

• Journal of Welding and Joining
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• v.17 no.6
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• pp.53-61
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• 1999

The use of thick plate in increasing in recent years due to the rapid expansion of chemical plants, nuclear plants, ships and other industrial plants. Welding is the most popular joining techniques employed in manufacturing industrial machineries and structures. Normally, Groove shapes are prepared according to appropriate rules and regulations such as KS, JIS, AWS, LR, DNV and etc. for various thicknesses of plate. However those groove angles tend to be too large. As a result of large groove angle, residual stress, deformation of material and strength reduction is obtained. Therefore, the reliability and safety of structures and machinery tend to be decreasing. Therefore, in this paper, theoretical as well as experimental study are carried out to find optimum groove shapes for T-welded joint of mild steel. The test specimen are made in same condition with simulation model. Welding residual stresses measurement by sectional cutting method. ⅰ) The mechanical difference for change the thickness of plate and groove angle are not appeared. ⅱ) In a mechanical point of view minimum preparation angle(40°) is more suitable than maximum groove angle(60℃). ⅲ) The measurement value and distribution of welding residual stresses are not effected largely by groove angle. It is mechanical restraint that mainly affect welding residual stresses distribution. In mechanical point of view minimum groove angle is more suitable than maximum groove angle. Therefore, it is appropriate to minimize the size of groove shape in strength and safety.

• Journal of Computational Design and Engineering
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• v.3 no.2
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• pp.151-160
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• 2016

Cutter-workpiece engagement (CWE) is the instantaneous contact geometry between the cutter and the in-process workpiece during machining. It plays an important role in machining process simulation and directly affects the calculation of the predicted cutting forces and torques. The difficulty and challenge of CWE determination come from the complexity due to the changing geometry of in-process workpiece and the curved tool path of cutter movement, especially for multi-axis milling. This paper presents a new method to determine the CWE for general milling processes. To fulfill the requirement of generality, which means for any cutter type, any in-process workpiece shape, and any tool path even with self-intersections, all the associated geometries are to be modeled as triangle meshes. The involved triangle-to-triangle intersection calculations are carried out by an effective method in order to realize the multiple subtraction Boolean operations between the tool and the workpiece mesh models and to determine the CWE. The presented method has been validated by a series of case studies of increasing machining complexity to demonstrate its applicability to general milling processes.

• Journal of the Korean Wood Science and Technology
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• v.29 no.2
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• pp.100-108
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• 2001

An understanding of potential lumber cutting yields may lead to increased utilization of the lower grades of lumber in wood industry. Computer simulations of rough-mill operations require a lumber database as input to give reasonable estimates of such yields. The lumber database must contain detailed information regarding the location and type of defects, and then all manufacturing sequences can be tested with the same raw material. However, no suitable lumber database with mapped defects exists for Korean wood industry. In this study lumber databases of Pinus densiflora S. et Z and Quercus acutissima which are the main Korean domestic species were developed to prepare for coming era of "utilization of domestic species" in the near future. These databases were put into lumber cut-up simulation model(gang-rip-first simulator) to investigate the part yields. Gang-rip first simulation showed average part yields of 44.75% and 63.10% for Quercus acutissima and Pinus densiflora lumber database developed, respectively. In most cases process set-up of fixed blade best feed showed the best part yields and the level of acceptable defects could not make significant differences in part yields.