• 대한안전경영과학회지
• /
• 제3권3호
• /
• pp.221-230
• /
• 2001

The assembly tolerance design methods have applied linear or nonlinear programming methods and used simulation method and search algorithms to optimize the tolerance allocation of each part in an assembly. However, those methods are only considered to the relationship between tolerance and manufacturing cost, which do not consider a quality loss cost for each part tolerance. In this paper, the integrated simulation model used genetic algorithm and the Monte-Carlo simulation method was developed for the allocation of the optimal tolerance considering the manufacturing cost and quality loss cost.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 1999년도 추계학술대회 논문집
• /
• pp.217-217
• /
• 1999

The main objective of this study is to simulate the design and operational policies of the assembly shop of an automotive plant for planning purposes and to find possible improvements. The simulation study was used to answer the following questions: How does the sequence affect the daily throughput\ulcorner What are the bottlenecks to the assembly lines in a given scenario\ulcorner A Simulation model was developed in accordance with the objective of this study. The model incorporates detailed workstation logic to accurately model downtime results through the use of a pull cord system. It is written with SIMAN. The discrete event feature of SIMAN does not adequately model the conveyor systems of the asembly shop. As a result, a few subroutines were added to the SIMAN modeling structures to mimic the operations of the assembly shop. Use of the model uncovered attractive improvement opportunities, such as a tremendous gain in annual volume if four additional spaces were added to a between-line buffer.

• 대한산업공학회지
• /
• 제27권1호
• /
• pp.95-102
• /
• 2001

The design of automobile body assembly line is one of essential parts for improving the process performance. The major objective of this research is to develop a performance evaluation model for automobile assembly line using a closed queueing network(CQN) and simulation method. In this study we used a two-step approach to compute the performance of the assembly line : first, we used CQN model considering assembly line equipments and the line operating time under the assumption of no failure, and second we used a well-known simulator FACTOR/AIM. Finally we implemented this model on a K automobile company and we have shown the sample results of automobile body assembly line.

• International Journal of Automotive Technology
• /
• 제7권2호
• /
• pp.217-226
• /
• 2006

To maintain competitiveness in the modern automotive market, it is important to carry out process planning concurrently with new car development processes. Process planners need to make decisions concurrently and collaboratively in order to reduce manufacturing preparation time for developing a new car. Automated generation of a simulation model by using the integrated process plan database can reduce time consumed for carrying out a simulation and allow a consistent model to be used throughout. In this research, we developed a web-based system for concurrent and collaborative process planning and flow analysis for an automotive general assembly using web, database, and simulation technology. A single integrated database is designed to automatically generate simulation models from process plans without having to rework the data. This system enables process planners to evaluate their decisions quickly, considering various factors, and easily share their opinions with others. By using this collaborative system, time and cost put into the assembly process planning can be reduced and the reliability of the process plan would be improved.

• 대한조선학회논문집
• /
• 제46권1호
• /
• pp.78-86
• /
• 2009

A capacity calculation and process analysis is a very important part for the entire ship production planning. Ship's production plan is set up with a concept that the product is produced based on the capacity achievable by the processes while general manufacturing sets up the production plan based on product lead-time. Therefore, in case the calculation of capacity for each process of shipbuilding yard is different from actual conditions, a series of production plan - ship table composition, dual schedule plan and execution schedule plan, etc - may accumulate errors, lose reliability of planning information and cause heavy cost deficit in this course. In particular, in case of new shipbuilding yard, stocks between processes are built up and half blocks are not supplied in timely manner, and that is sometimes due to the clumsiness of the operator but it is more often because of the capacity to execute each process is not logically calculated. Therefore, this paper presents the process to calculate the assembly leadtime and assembly process capacity for shipbuilding yard assembly factory. This paper calculated the block type for calculation of assembly lead time based on block DAP(detailed assembly procedure), and introduced cases that calculate production capacities by assembly surface plate by considering the surface plate occupied area of the blocks that change depending on assembly field area and assembly processes through assembly simulation.

• Journal of Welding and Joining
• /
• 제30권1호
• /
• pp.78-84
• /
• 2012

Due to the inherent dimensional uncertainty, tolerances accumulate in the final assembly. Tolerance accumulation has serious effect on the performance of ECV assembly. This paper proposes a method of tolerance accumulation analysis using Monte Carlo simulation, which includes welding process in assemble process. This method can predict the final tolerance distributions of the completed assembly with the prescribed statistical tolerance distribution of each part to be assembled. With the inclusion of welding, another dimensional uncertainties due to partial melting is to be accounted as well. Partial melting of projection height was included in the tolerance propagation analysis. Verification of the proposed method was performed by making use of Monte Carlo simulation. Monte Carlo simulation results showed promising results in that we can predict the final tolerance distributions in advance before actual assembly process of precision machinery.

• 한국산학기술학회논문지
• /
• 제10권7호
• /
• pp.1439-1445
• /
• 2009

본 논문에서는 디지털 도어록 혼류 조립 공정에서의 시뮬레이션 분석모델을 제안한다. 이 모델의 목적은 디지털 도어록 생산 공정 설계에 있어서 여러 대안의 성능에 대해 평가하는 것이다. 시뮬레이션 모델을 개발하기 위하여 먼저 시간연구가 수행되었다. 동시에 ARENA 시뮬레이션 도구를 이용하여 공정분석을 수행하였다. 그 결과 현재의 디지털 도어록 혼류 생산 공정은 여러 품종의 수요 증가에 적절한 생산방식을 제공하지 못한다는 문제점을 발견하였고 이를 개선하기 위한 대안을 제안하였다.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2009년도 추계학술발표논문집
• /
• pp.715-718
• /
• 2009

The assembly line is one of the typical process hard to analyze with mathematical methods including even stochastic approaches, because it includes many manual operations varying drastically depending on operators' skills. In this paper, we suggest the simulation optimization method to design the optimal assembly line of a gas oven. To achieve the optimal design, firstly, we modeled the real gas oven assembly line with actual data, such as assembly procedures, operation rules, and other input parameters and so on. Secondly, we build some alternatives to enhance the line performance based on business rules and other parameters. The DOE(Design Of Experiment) techniques were used for testing alternatives under various situations. Each alternatives performed optimization process with evolution strategy; one of the GA(Genetic Algorithm) techniques. As a result, we can make about 7% of throughputs up with the same time and cost. By this process, we expect the assembly line can obtain the solution compatible with their own problems.

• 한국CDE학회논문집
• /
• 제10권2호
• /
• pp.133-142
• /
• 2005

This paper proposes an object-oriented conceptual information model of mechanical assemblies, named open assembly model (OAM). The proposed assembly model primarily defines hierarchical relationships between parts and subassemblies. Together with the assembly hierarchy. the model also provides a way to represent tolerances, kinematic information, and parametric assembly constraints. Relational information such as mating conditions and degree of freedom between parts and subassemblies is captured via assembly features and relationships thereof. The information model is described using class diagrams of the Unified Modeling Language (UML), and instance diagrams are used to exemplify the proposed information model. The conceptual model presented in this paper is an integrated information model for assembly representation, which could supply necessary information for tolerance analysis and synthesis, kinematic simulation, and assembly simulation. Such a conceptual information model plays an important role for the exchange of information between modeling, analysis and planning systems. Hence, the proposed model could serve as a framework for developing data exchange standards of mechanical assemblies. The proposed model is demonstrated through a case study of a planetary gear assembly.

• 산업경영시스템학회지
• /
• 제40권4호
• /
• pp.211-220
• /
• 2017

The application of the theoretical model to real assembly lines has been one of the biggest challenges for researchers and industrial engineers. There should be some realistic approach to achieve the conflicting objectives on real systems. Therefore, in this paper, a model is developed to synchronize a real system (A discrete event simulation model) with a theoretical model (An optimization model). This synchronization will enable the realistic optimization of systems. A job assignment model of the assembly line is formulated for the evaluation of proposed realistic optimization to achieve multiple conflicting objectives. The objectives, fluctuation in cycle time, throughput, labor cost, energy cost, teamwork and deviation in the skill level of operators have been modeled mathematically. To solve the formulated mathematical model, a multi-objective simulation integrated hybrid genetic algorithm (MO-SHGA) is proposed. In MO-SHGA each individual in each population acts as an input scenario of simulation. Also, it is very difficult to assign weights to the objective function in the traditional multi-objective GA because of pareto fronts. Therefore, we have proposed a probabilistic based linearization and multi-objective to single objective conversion method at population evolution phase. The performance of MO-SHGA is evaluated with the standard multi-objective genetic algorithm (MO-GA) with both deterministic and stochastic data settings. A case study of the goalkeeping gloves assembly line is also presented as a numerical example which is solved using MO-SHGA and MO-GA. The proposed research is useful for the development of synchronized human based assembly lines for real time monitoring, optimization, and control.