• 한국국방경영분석학회지
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• 제22권2호
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• pp.113-125
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• 1996

'Bowl Phenomenon' refers to allocating the work loads to middle stages slightly less than the outer ones in a series production system. Millier and Boling(1966) first discovered that the output rate of a production line were obtained by deliberately unbalancing, like a bowl-shape, under certain circumstances. So far quite a many researches have been studied either theory-oriented or simulation-oriented on this topic. However the papers concerning assemble production line are rather rare possibly due to the system complexity. In this paper, a simulation work on a 6-node assembly line has been conducted with the help of SLAMSYSTEM software. The simulation results have been turned out that 1) the Bowl phenemenon is still valid in the given system, 2) buffer storage between the work stations are critical measure for determining the degree of work-load unbalancing.

• 한국경영과학회지
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• 제30권1호
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• pp.43-54
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• 2005

A flexible assembly line (FAL) is a production system that assembles various parts in unidirectional flow line with many constraints and manufacturing flexibilities. In this research we deal with a FAL balancing problem with the objective of minimizing the maximum workload allocated to the stations. However, almost all the existing researches do not appropriately consider various constraints due to the problem complexity. Therefore, this study addresses a balancing problem of FAL with many constraints and manufacturing flexibilities, unlike the previous researches. We use a genetic algorithm (GA) to solve this problem. To apply GA to FAL. we suggest a genetic representation suitable for FAL balancing and devise evaluation method for individual's fitness and genetic operators specific to the problem, including efficient repair method for preserving solution feasibility. After we obtain a solution using the proposed GA. we use a heuristic method for reassigning some tasks of each product to one or more stations. This method can improve workload smoothness and raise work efficiency of each station. The proposed algorithm is compared and analyzed in terms of solution quality through computational experiments.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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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.

• 한국컴퓨터정보학회논문지
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• 제21권2호
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• pp.97-103
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• 2016

This paper deals with the cycle time minimization problem that determines the productivity in printed circuit board (PCB) with n components using the m placement machines. This is known as production cycle time determination problem (PCTDP). The polynomial time algorithm to be obtain the optimal solution has been unknown yet, therefore this hard problem classified by NP-complete. This paper gets the initial assignment result with the machine has minimum unit placement time per each component firstly. Then, the balancing process with reallocation from overhead machine to underhead machine. Finally, we perform the swap optimization and get the optimal solution of cycle time $T^*$ within O(mn) computational complexity. For experimental data, the proposed algorithm can be obtain the same result as integer programming+branch-and-bound (IP+B&B) and B&B.

• 대한안전경영과학회지
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• 제19권1호
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• pp.203-210
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• 2017

Companies are pursuing the management of small quantity batch production or JIT(Just-in-time) system for improving the delivery response and LOB(Line Balancing) in order to satisfy consumers' increasing demands in the current global economic recession. And in order to improve the growth of production for reducing manufacturing cost, improvements of the Load Balancing have become an important reformation factor. Thus this paper is aimed at warehouse which procures materials on the assembly line in procurement logistics of automotive logistics and proceed with research on heuristic algorithm development which can increase the Load Balancing of workers. As a result of this study, when applied the primary target value, it was verified that the whole workers decreased from 28 to 24. Furthermore, when specified the secondary target value and applied algorithm once more, it was verified that the Load Balance Ratio was improved from 44.96% to 91.7%.

• Industrial Engineering and Management Systems
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• 제10권3호
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• pp.197-202
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• 2011

In traditional production lines, such as assembly lines, each worker is usually assigned to a particular fixed work, and decreasing the task to master the assigned work is valuated. However, when an imbalance exists between workers' speeds, if a worker delays the overall work in the production line, the production rate of the particular line will also decrease. To avoid this problem, the "Self-Balancing Production Line" was introduced. In this type of production line, each worker is assigned work dynamically, and when specific conditions are satisfied, production remains balanced. Characteristics of these lines that can be preempted at any place have already been analyzed by some researchers. A previous paper examined the situation in which only a single worker can process one machine and cannot preempt processing, and the improved policy of an ordinary selfbalancing production line, which specifies which stations workers can process and how workers can behave. This policy achieveda high production rate with only four stations and two workers (Buzacott, 2002). In that paper, worker processing stations and the behavior of a specific worker were limited, andthe paper focused only on specific stations and workers. Therefore, it is not applicable to any worker sequence. In this paper, we focus on other ways to decrease cycle time. In this kind of line, a worker processes at his or her speed. Therefore, if a worker is assigned stations according to his or her speed, the line can decrease cycle time. To do so, we relax the assumptions of this type of line and set a new condition. Under these conditions, we compare our results to the results of previous papers.

• 한국시뮬레이션학회논문지
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• 제29권4호
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• pp.95-109
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• 2020

이 논문에서는 자동차 차체 조립라인과 같은 제조시스템을 설계할 때, 설비투자비용과 같은 다양한 비용요소를 고려하여 최적 배치안을 결정하는 문제를 다룬다. 시스템의 성능 평가에 필요한 생산율 재공품 재고 수준을 추정하기 위해서는 시뮬레이션 실험 결과를 기반으로 하는 메타모델 방법론을 사용하였다. 최적화 문제의 목적함수는 목표생산율을 만족시키는 최소비용으로 정하였는데, 비용요소로는 로봇, 버퍼, 운송장비에 대한 투자비용을 고려하였고, 운영비용으로는 재공품 재고비용을 포함시켰다. 최적화 문제를 풀기 위해서는 하모니 탐색방법론을 사용하였다.

• Design & Manufacturing
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• 제14권1호
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• pp.8-14
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• 2020

In general, auto parts production assembly line is assembled and produced by automatic mounting by an automated robot. In such a production site, quality problems such as misalignment of parts (doors, trunks, roofs, etc.) to be assembled with the vehicle body or collision between assembly robots and components are often caused. In order to solve such a problem, the quality of parts is manually inspected by using mechanical jig devices outside the automated production line. Automotive inspection technology is the most commonly used field of vision, which includes surface inspection such as mounting hole spacing and defect detection, body panel dents and bends. It is used for guiding, providing location information to the robot controller to adjust the robot's path to improve process productivity and manufacturing flexibility. The most difficult weighing and measuring technology is to calibrate the surface analysis and position and characteristics between parts by storing images of the part to be measured that enters the camera's field of view mounted on the side or top of the part. The problem of the machine vision device applied to the automobile production line is that the lighting conditions inside the factory are severely changed due to various weather changes such as morning-evening, rainy days and sunny days through the exterior window of the assembly production plant. In addition, since the material of the vehicle body parts is a steel sheet, the reflection of light is very severe, which causes a problem in that the quality of the captured image is greatly changed even with a small light change. In this study, the distance between the car body and the door part and the door are acquired by the measuring device combining the laser slit light source and the LED pattern light source. The result is transferred to the joint robot for assembling parts at the optimum position between parts, and the assembly is done at the optimal position by changing the angle and step.

• 산업경영시스템학회지
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• 제44권2호
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• pp.93-101
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• 2021

The purpose of this study is to analyze the adequacy of production capacity of the assembly process system of mobile bath vehicle's top box panel and process design through a simulation analysis. Towards this end, the layout of the facility designed with pre-verification job using a simulation modeling and an experiment, and facility, logistics process, and personnel input method were made into a simulation model, and the design system's adequacy was evaluated through an experiment. To produce 120 mobile bath vehicles annually, it was analyzed that 14 general workers and seven skilled workers were adequate through the experiment. It was also identified that three painting process lines carried out through outsourcing were adequate. Production lead time was 201.7 hours on average and it was 230 hours maximum. To meet customer delivery service level of 95% within the deadline when establishing a customer order and vehicle delivery plan, it was analyzed that more than 215 hours of lead time is needed minimum. If the process cycle time is reduced to 85% upon system stabilization and skillfulness improvement, it was analyzed that annual output of 147 vehicles can be achieved without additional production line expansion.

• 한국산업융합학회 논문집
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• 제13권1호
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• pp.49-54
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• 2010

Lean 6 sigma has recently been used to describe a management system which combines lean management and 6 sigma. The marriage between Lean manufacturing and 6 sigma has proven to be a powerful tool for cutting waste and improving the organization operations. Time and quality are the most important metrics in improving any company's production and profit performance. lean 6 sigma is a management innovation for improving production efficiency, process quality, cost reduction, investment efficiency and customer's satisfaction. in this paper, Advanced cell line is builded the home appliance goods of the LCD TV final assembly line of domestic company line, training the multi-skilled man and controlling the production information system based on Lean 6 sigma.