• Journal of Welding and Joining
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• 제33권6호
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• pp.13-20
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• 2015

Many automotive companies are endeavoring to improve the quality of resistance spot welding by updating body-in-white (BIW) production line with adaptive control spot welding system to compensate the process disturbances such as gap, electrode wear, oxidized surfaces, poor fit up and adhesive etc. Most of the commercial adaptive weld controllers require proper "Initial Welding Schedule" or "Reference weld" to achieve compensation in welding parameters during real time welding. In this study, the compensation of a commercial adaptive weld controller had been observed and analyzed thoroughly for various process disturbances to find optimal initial welding schedule. It was observed that 90 percent of the expulsion current in constant current control as reference welding schedule conferred the maximum button diameter in adaptive control welding. Finally, effects of each disturbance in combined field disturbances system with adaptive control had also been confirmed with the design of experiment (DOE) by minitab(R)16 for combined disturbances situation and suitability of optimum initial weld current had also established with real body part validation test.

• 대한기계학회논문집A
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• 제20권1호
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• pp.14-23
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• 1996

Scheduling jobs effectively under consideration of actual loads on machines is one of the most complicated tasks in production control. The complexity of the finite capacity scheduling often makes the conventional methods of industrial engineering fail. As an alternative, Knowledge-based approaches to job-shop scheduling have been evolved recently. This paper presents a blackboard- based scheduling expert system which combines knowledge-based scheduling with interactive scheduling. It is shown to be possible to generate the feasible schedule within a reasonable time. Flexible reaction management is also possible while keeping the changes in the generated schedule to the minimal and adjusting the schedule to tardy operations or working environmental changes. The system is equipped with a rule base with heuristics for handling conflicted event. A case study applying the implemented system is described.

• 한국인터넷방송통신학회논문지
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• 제14권6호
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• pp.199-205
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• 2014

효과적인 중소기업 정보화를 위하여 표준화된 생산정보화 시스템 개발 방법론(PSDM)을 통하여 단계별 주요 업무에 대한 작업을 정의하고 관련 연관도를 통하여 업무에 대한 선행 및 후행 관계를 정의한 후 그에 따른 프로젝트 범위 일정 비용 인적자원 관리를 위한 최적의 업무분류체계(WBS : Work Breakdown Structure)를 연구개발 하고자한다. 시스템의 신뢰성 품질 생산성 향상을 위한 관리 항목 설정, 중소기업 IT업체 감리업체 등 참여 기업간의 의사소통, 그리고 구축된 생산정보화의 유지보수를 포함한 운영지원 등 보다 체계적이고 효율적인 시스템 구축을 위해 중소기업 생산정보화에 적합한 WBS의 연구로 생산정보화를 구축하고자 참여하는 많은 중소기업 및 IT업체들이 표준화된 방법론을 이용하여 시스템 구축을 보다 효과적으로 수행할 수 있으며, 보다 높은 신뢰성을 가진 시스템을 계획된 개발 일정에 알맞게 구축한다.

• 한국콘텐츠학회논문지
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• 제8권9호
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• pp.84-93
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• 2008

2005년부터 장편 3D 애니메이션 제작의 세계적인 증가추세와 하드웨어와 소프트웨어의 기술적 진보가 시각적 표현의 한계치를 넘어설 정도가 되면서 전체 작업 공정 중에서 렌더링(rendering)이 차지하는 비중이 더욱 중요하게 되었다. 렌더링 직전의 최종 파일은 데이터의 크기가 증가하는 문제가 발생한다. 이것은 수정 작업 시에 대용량 파일을 불러오고 저장하는 불필요한 소요시간과, 수정할 부분 외에 전체적으로 다시 렌더링을 수행하게 되는 시간을 소모하게 만든다. 본 논문에서는 연구 방법으로 Maya API를 활용하여 렌더링 레이어들의 정보 수정 방법을 연구하고 이를 적용하여 렌더링을 실행하는 Tool을 구현하는 것이다. 연구결과, 상업적인 애니메이션 제작에서는 제작 일정의 준수는 매우 중요하다. 그러므로 수정 작업에서 효율을 극대화 할 수 있기 위하여 독립적인 렌더링 툴 기반의 레이어 렌더링 구현이 필요하다고 판단된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.601-602
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• 2006

The primary role of MRP(Material Requirement Planning) is to make a production plan so that we have an exact quantity of right materials on needed time at right place. But the ignorance on capacity constraints makes some problems whenever production schedule is established. To increase the performance of MRP system, a novel approach which is based on new input data structure is suggested. The new input data structure includes all the information about Material BOM, Routing and resource data so that we can easily examine the usage of resources and generate higher performance production plans.

• 산업공학
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• 제11권2호
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• pp.159-176
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• 1998

In the motor manufacturing system with the properties of short delivery and order based production, the process plan is performed individually for each order by the expert of process plan after the completion of the detail design process to satisfy the specification to be required by customer. Also it is hard to establish the standard process plan in reality because part routings and operation times are varied for each order. Hence, the production planner has the problem that is hard to establish the production schedule releasing the job to the factory because there occurs the big difference between the real time to be completed the process plan and the time to be required by the production planner. In this paper, we study the decision supporting system for the process plan based on knowledge base concept. First, we represent the knowledge of process planner as a database model through the modified POI-Feature graph. Then we design and implement the decision supporting system imbedded in the heuristic algorithm in the client/server environment using the ORACLE relational database management system.

• 산업공학
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• 제19권1호
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• pp.34-42
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• 2006

This paper presents a scheme for a hierarchical production scheduling and control system for a refrigerator factory with mixed model assembly lines. The setting of the factory is as follows. There are three mixed-model assembly lines called main line A, B and C and two batch lines that supply parts to the main lines. For each of the main lines, three work-centers are dedicated to them. The sub-lines and work-centers produce parts in batch type. An incoming production order from the master planner is characterized by its product type, amount, and due date. Under this situation, the proposed scheme has several features to schedule and control the above mentioned factory; 1) select the starting time and the place (assembly line) for an order processing, 2) devise a way to control orders to be processed as scheduled, and 3) reschedule orders when something unexpected happen. Finally, this paper provides a case study where the proposed scheme is applied to.

• 대한산업공학회지
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• 제21권3호
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• pp.357-369
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• 1995

Wafer fabrication process is the most important and critical process in semiconductor manufacturing. The process is very complicated and hard to establish an efficient schedule due to its complexity. Furthermore, several performance indices such as due dates, throughput, cycle time and workstation utilizations are to be considered simultaneously for an efficient schedule, and some of these indices have negative correlations in performances each other. We develop an efficient heuristic scheduling algorithm; Hybrid Input Control Policy and Hybrid Dispatching Rule. Through numerical experiments, it is shown that the proposed Hybrid Scheduling Algorithm gives better performance compared with existing algorithms.

• Industrial Engineering and Management Systems
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• 제7권3호
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• pp.204-213
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• 2008

Companies that produce capital goods need to schedule the production of products that have complex product structures with components that require many operations on different machines. A feasible schedule must satisfy operation and assembly precedence constraints. It is also important to avoid deadlock situations. In this paper a Genetic Algorithm (GA) has been developed that includes a new repair process that rectifies infeasible schedules that are produced during the evolution process. The algorithm was designed to minimise the combination of earliness and tardiness penalties and took into account finite capacity constraints. Three different sized problems were obtained from a collaborating capital goods company. A design of experimental approach was used to systematically identify that the best genetic operators and GA parameters for each size of problem.

• 경영과학
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• 제29권2호
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• pp.143-155
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• 2012

The purpose of this study is to formulate and solve the scheduling problem to heat-treatment process in forging process and apply it to industries. Heat-treatment is a common process in manufacturing heavy forged products in ship engines and wind power generators. Total complete time of the schedule depends on how to group parts and assign them into heat furnace. Efficient operation of heat-treatment process increases the productivity of whole production system while scheduling the parts into heat-treatment furnace is a combinatorial problem which is known as an NP-hard problem. So the scheduling, on manufacturing site, relies on engineers' experience. To improve heat-treatment process schedule, this study formulated it into an MIP mathematical model which minimizes total complete time. Three methods were applied to example problems and the results were compared to each other. In case of small problems, optimal solutions were easily found. In case of big problems, feasible solutions were found and that feasible solutions were very close to lower bound of the solutions. ILOG OPL Studio 5.5 was used in this study.