• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.859-860
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• 2010

• IE interfaces
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• v.11 no.2
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• pp.1-11
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• 1998

In this paper, a case study is introduced on the development on a production planning system for the efficient control of work-in-process material flows. A special attention has been given to the prevention of the shortage of the automobile-components at the auto-assembly lines and the dynamic adaptation of the production plan to the continuously changing environment. The expertise of the production planner is analyzed and transformed into the logic of the software developed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.1
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• pp.56-69
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• 2001

Objectives : This study was designed to develop and standardize a checklist for ergonomic risk factors, and to provide ergonomic guidelines for managing cumulative trauma disorders (CTDs) in automobile assembly lines. Methods : The Checklist for Ergonomic Risk Factors (CERF-1) was developed based on the results of previous studies, and then modified after performing pilot study. Information on the symptoms possibly related with CTDs was obtained using a self-reported Questionnaire from 465 automobile assembly workers. Their job conditions were examined to assess risk factors through both direct observation and video analysis. Results : Rate of detecting risky job through CERF-1 was 85.6%, and was similar to that (88.8%) by Occupational Safety and Health Adminstration(OSHA) checklist but higher than that (63.7%) by American National Standards Institute(ANSI) Z-365. Relationship of the exposure scores derived from CERF-1 with levels of symptom was greater (r=0.49) than OSHA (r=0.28) and ANSI Z-365 (r=0.22). Considering the relationship, jobs scoring higher than 16 could be classified as the Risk Job. and lower than 16 as the Low Risk Job. Sensitivity and specificity of the Risk Job were 92.5 % and 31.5 %, respectively. Odds ratio (OR) after age adjustment was 5.69 (95 % confidence interval 3.15-10.29) for the Risk Job, and these ORs were significantly different from those of the Low Risk Job. The exposure scores were Quite valid, in that the scores at the main survey were significantly correlated with those at the follow-up survey, as suggested by test-retest(r=0.88) and inter-rater reliability(r=0.80). Conclusions : The CERF-1, developed in this study, will be an efficient tool for evaluation of risk jobs for CTDs in automobile assembly lines, and can be used easily by health care providers.

• IE interfaces
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• v.9 no.2
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• pp.39-45
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• 1996

This paper investigates the problems of grouping N products on an assembly line with an objective of maximizing the option grouping rate. Before developing a mixed model grouping algorithm, simulation studies are committed for developing operating rules and evaluating the layout production systems. A mixed model grouping algorithm is suggested and it is applied to the color selection lane in automobile production system, which reveals a high mixed model grouping rate.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.3
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• pp.26-30
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• 1996

The successful development of the automobile industry in Korea is the firstfruit of the epochmaking automobile policy in 1973: Top-Down mass production of Korean model cars. In Top-Down system, indigenous model, which is the most important and difficult part of the automobile industry, is devised first, followed by the mass production of the major parts, such as bodies, engines, etc. This system is in contrast to the prevailing Bottom-up system in the third-world, which assembles automobiles by gradually adding up simple domestic parts. The Government, faced with a vicious circle of depen- dence on assembly of foreign cars, high prices, small demand and low production, decided it was time to move to the mass production of the indigenous models. It was hoped that the efficiencies of low cost Korean models would be epochally improved by overcoming the sway of foreign models and by strengthening the production capabilities of the main parts. In contrast to these develop- ment planning, assembled vehicles numbered only 26,300 units in 1973. In the year of 1995, the total number of automobile production have already passed 2,534,000. As steady growth in worldwide demand is forecast, Korea will able to play a major role as an important automobile maker of the next century.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.1
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• pp.23-32
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• 1997

In this paper, systematic approach is studied about assemblability and disassemblability of parts in order to reduce the assembly cost, and to disassemble products easily which is possible to recycle the parts. For this purpose, we selected one subassembly, and analysed assembly and disassembly process. From this result, we found the weakpoints of assembly and disassembly process, and then, the influencing parameters of assemblability and disassemblability are defined. On the basis of the analysis of these parameters we grasped the interrelation between assemblability and disassemblability. And, guidelines for assemblability and disassemblability are developed. Finally design alternatives are evaluated quantitatively in the aspects of assembly and disassembly by using the guidelines which developed in this research.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.4
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• pp.109-118
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• 2012

Large number of part design for aircraft and automobile is preceded by functional or sectional design groups for efficiency. However, interferences and gaps can be found when the parts and sub-assemblies by those design groups are to be assembled. These interferences and gaps cause design changes and additional repair processes. While interference problem has been resolved by digital mockup and concurrent engineering methodology, gap problem has been covered by temporary treatment of filling gap with sealant. This kind of fast fix causes fatal problem of leakage when the gap is too big for filling or the treatment gets old. With this research, we have developed a program to find the gap automatically among parts of assembly so that users can find them to correct their design before manufacturing stage. By using decomposition model representation method, the developed program can search the gap among complex car body parts to be visualized with volumetric information. It can also define the boundary between the gap and exterior empty space automatically. Though we have proved the efficiency of the developed program by applying to automobile assembly, application of the program is not limited to car body only, but also can be extended to aircraft and ship design of large number of parts.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.50-56
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• 2004

The directional ability of an automobile has an influence on driver directly, and hence it must be given most priority. Alignment factors of automobile such as the camber, caster and toe directly affect the directional ability of a vehicle. The above mentioned factors are determined by the pose of interlinks in the assembly of an automobile front chassis module. Measuring the position of center point of ball joints in the front lower arm is very difficult. A method to determine this position is suggested in this paper. Pose estimation for front chassis module and dimensional evaluation to find the rotational characteristics of front lower arm were developed based on fundamental geometric techniques. To interpret the inspection data obtained for front chassis module, 3-D best fit method is needed. The best fit method determines the relationship between the nominal design coordinate system and the corresponding feature coordinate system. The least squares method based on singular value decomposition is used in this paper.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.63-67
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• 2001

Springback after drawing and trimming is regarded as one of the most influential factors during forming structural frames since the part dimensions have dominant effect on assembly quality at later stages. In this study, analytical results were obtained from a commercial FEM package for an outer rear frame of an automobile. In terms of springback and twist the effect of forming process is compared and discussed between open and closed-ends forming

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.19-20
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• 2008