• Journal of Korean Institute of Industrial Engineers
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• v.19 no.1
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• pp.1-17
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• 1993

It is well known that an assembly operation is usually constrained by the geometric interference between parts. These constraints are normally presented as AND/OR precedence relationships. To find a feasible assembly sequence which satisfies the geometric constraints is not an easy task because of the TSP(Traveling Salesman Problem) nature with precedence constraints. In this paper, we developed an automated system based on Neural Network for generating feasible assembly sequences. Modified Hopfield and Tank network is used to solve the problem of AND/OR precedence-constrained assembly sequences. An economic assembly sequence can be also obtained by applying the cost matrix that contains cost-reducing factors. To evaluate the performance and effectiveness of the developed system, a case of automobile generator is tested. The results show that the developed system can provide a "good" planning tool for an assembly planner within a reasonable computation time period.

• The Journal of the Korea Contents Association
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• v.16 no.12
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• pp.143-150
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• 2016

Modular house is built by assembling various joints. Module assembly in the stage of on-site installation is very important process, because assembly process directly affects the structural stability and the quality. However, manual tools and electric-powered tools have a problem in that assembly productivity and quality are reduced during long-time usage. Although pneumatic assembly tools for modular house have been developed, but empirical analysis to compare and evaluate the performance of tools has not been sufficient. This study compares and analyzes the assembly quality and productivity by applying existing assembly tools and new pneumatic tools to the field. The analysis results show that pneumatic assembly tools are more excellent in terms of assembly productivity and quality.

• Korean Journal of Computational Design and Engineering
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• v.7 no.3
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• pp.170-176
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• 2002

To exchange CAD data between heterogeneous CAD systems, we generally use a neutral format especially STEP, which is the international standard (ISO-10303) for product model data exchange. AP214 (Application Protocol) for the automotive industry not only takes into account geometry and organizational data, but also provides a classification mechanism for product modeling. When reading a STEP file during a design process that is exported from other CAD systems, it is a burden to a designer to go through the tedious process of removing duplicate or non-manifold entities, adjusting parts, and rearranging text. We analyze the structure of AP214 and develop a healing tool to solve the following problem. Without the assembly information in the Master workspace of CATIA, or to read a STEP file from Pro/Engineer, a designer should do a repetitive process of disintegrating an assembly into parts one by one. We have developed a post-processing tool for STEP AP214 that separates out a part from an assembly model and adjusts superfluous or useless entities using the ACIS kernel.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.178-183
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• 2010

Base-mounted type(BMT) driving assembly in CNC machine tools is an indispensable part to improve productivity by reducing tool changeover time and to meet the ever-increasing demand of precision machine tools. This study aimed to perform finite element analysis and geometric parameter optimization to improve the efficiency of BMT driving assembly. First, simulations for three-dimensional structural and vibration analysis were performed using ANSYS/Workbench on the initial geometric models of BMT driving assembly. After analyzing stress and deformation concentration zones, several new geometrical models were designed and evaluated by design of experiments and ANSYS/DesignXplorer. Through a series of analysis-evaluation-modification cycles, it was seen that designed models were effective in determining optimal geometry of BMT driving assembly.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.2
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• pp.103-114
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• 2023

Objectives: This study was conducted to evaluate hand-arm vibration (HAV) exposure levels due to the use of power hand tools and to evaluate the determinants in the automobile assembly process. Methods: The exposure level to HAV was evaluated for 30 work lines in five assembly processes (body, engine, chassis, door, and design) that use air-powered tools and battery-powered tools and operate in circulation for two hours. The 2-hr equivalent energy vibration acceleration, A (2), of the task was measured. The 8-hr equivalent energy vibration acceleration, A (8), was estimated in consideration of the number of tasks that can be performed per day by each process. In addition, a survey on the working environment was conducted with workers exposed to vibration. Results: The geometric mean of the HAV exposure level, A (2), for a total of 30 tasks was 2.51 m/s², and one case was 10.30 m/s², exceeding TLV (2hr). The HAV exposure level of A (8) was evaluated from 1.03 m/s² to 5.36 m/s². A (2) showed a statistically significant difference (P<0.01) for each process, and the chassis process (GM=3.90 m/s²) was the highest. The larger the tool size and the longer the tool length, the higher was the vibration acceleration when using a battery-powered tool than an air-powered tool (P<0.01). Battery-powered tool users showed higher dissatisfaction on all items than did air-powered tool users. Conclusions: As a result of this study, it is necessary to implement a program to reduce the HAV exposure levels.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.47-52
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• 2002

There are many factors in machine tool error. These are thermal deformation, geometric error, machine's part assembly error, error caused by tool bending. Among them thermal error is 70% of total error of machine tool . Prediction of thermal error is very difficult. because of nonlinear tendency of machine tool deformation. In this study, we tried thermal error prediction by using multi regression analysis.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1089-1094
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• 1993

A pilot system for flexible automatic assembly has been built at ASRI in Seoul National University. The system is designed for being capable of assembling different variants and products. The system consists of three industrial robots, four free-flow conveyors, automatic tool changers, RCC and fixtures. This paper describes the concept and the technical solutions of the developed flexible assembly cell. Results of performance evaluation using colored petri net are also presented and discuss.

• Korean Journal of Computational Design and Engineering
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• v.9 no.1
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• pp.62-76
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• 2004

Many customers are no longer satisfied with mass-produced goods. They are demanding customization and rapid delivery of innovative products. Many companies are now realizing that the best way to reduce life cycle costs is to evolve a more effective product development paradigm using Internet and web based technologies. Yet there remains a gap between current market demands and product development paradigms. The existing CAD systems require that product developers possess all the design analysis tools in-house making it impractical to employ all the needed and newest tools. Hence, this paper addresses how assembly operation analysis can be embedded transparently and remotely into a service-oriented collaborative assembly design environment. A new assembly operation analysis framework is introduced and a relevant architecture and tools are developed to realize the framework. Instead of the current sequential process for verifying and validating an assembly design, a new Virtual Assembly Analysis (VAA) method is introduced in the paper to predict the various effects of joining during actual collaborative design. As a case study, arc welding and riveting processes are investigated. New service-oriented VAA architecture and its VAA components are proposed and implemented on prototype mechanical assemblies.

• Korean Journal of Computational Design and Engineering
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• v.2 no.2
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• pp.103-110
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• 1997

In the development of large complex assembly, most design changes are from the following reasons.: 1) insufficient consideration of assembling sequence of downstream process. 2) interference and fit-up of related parts. 3) initial design changes which are not completely resolved. In order to reduce the first reason of above, the assembly-centric modeling methodology was proposed in the part (1) of the thesis. In this part (2), a Digital Mock-Up system, which is a tool to build a virtual mock-up in design stage, has been developed in order to prevent the other two reasons. The system can build a virtual assembly in various ways as followings.: 1) assembling parts which are located in user defined envelope. 2) assembling parts with the specified disciplines. 3) assembling parts that are selected in the part list. It can also make an assembly by the combination of above methods. In addition to that, it has the functions to read/write the virtual assembly and to explode parts of the assembly in desired direction. With the virtual assembly, engineers can design interference free parts without making physical mock-up. The system has been implemented with Oracle database management system in CATIA environment.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.183-188
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• 2002

Co-cured composite materials has its own characteristics, so its thermal expansion is different each other. The selection of tool material for co-cured composite part in high temperature more over $350^{circ}F$ and 50 Psi pressure have to consider part thermal expansion, size, shape, and economic aspect in production line. So it is important choose tooling material in manufacturing composite parts. We called the tool for airplane composite parts as BAJ (Bonding Assembly Jig). Composite parts are cured on the BAJ in autoclave. BAJ have to stable at high temperature over $350^{circ}F$ and 50 Psi pressure, Considering composite parts' dimensional tolerance compare to heat up in autoclave. This paper come from the results of the experiment at the composite parts production line and review other aircraft company's method for tooling This is for the engineer engaged in composite parts manufacturing.