Coping with disassembly yield uncertainty in remanufacturing using sensor embedded products

© 2011, Ilgin et al; licensee Springer.This paper proposes and investigates the use of embedding sensors in products when designing and manufacturing them to improve the efficiency during their end-of-life (EOL) processing. First, separate design of experiments studies based on orthogonal arrays are carried out for conventional products (CPs) and sensor embedded products (SEPs). In order to calculate the response values for each experiment, detailed discrete event simulation models of both cases are developed considering the precedence relationships among the components together with the routing of different appliance types through the disassembly line. Then, pair-wise t-tests are conducted to compare the two cases based on different performance measures. The results showed that sensor embedded products improve revenue and profit while achieving significant reductions in backorder, disassembly, disposal, holding, testing and transportation costs. While the paper addresses the EOL processing of dish washers and dryers, the approach provided could be extended to any other industrial product

Planning for selective disassembly considering condition of End-of-Life product and operation of disassembly line

학위논문(석사) -- 서울대학교대학원 : 공과대학 산업공학과, 2023. 2. 홍유석.현대 기업은 이윤뿐만 아니라 환경오염의 방지 및 개선을 위해 노력해야 한다. 그래서 제품을 단순히 생산하고 판매하는 것에서 그치지 않고 폐기 이후의 단계에 대해서도 깊이 고려해야 한다. 폐기 이후의 제품에 대해서 제품의 복구를 하게 되면 경제적, 환경적인 면에서 큰 효과를 볼 수 있다. 이를 위해서는 분해의 과정이 필수적인데, 효율적이고 경제적 분해계획을 수립하는 것이 중요하며, 이것이 분해에 관한 연구의 핵심이라고 할 수 있다. 본 연구에서는 검사에 기반을 둔 선택적 분해라는 프레임워크 하에서 폐기제품의 상태와 라인의 운영 측면을 동시에 고려하여 라인별 분해공정을 어떻게 구성할 것인지, 폐기제품의 상태에 따라 분류한 그룹별로 어느 라인에서 분해를 할 것인지를 동시에 결정하는 최적화 모델을 제안한다. 이는 제품 측면과 라인 측면을 동시에 고려한 분해계획 수립이라는 점에서 기존 연구와는 차별성을 갖는다. 폐기제품의 상태는 제품이 운영되었던 환경에 의해서 매우 다양하기 때문에 목표부품은 사전에 정해지는 것이 아니라 검사를 통해서 결정되며, 이 검사의 방법으로 분해 전 검사와 분해 후 검사로 나눌 수 있다. 그리고 분해라인을 어떻게 설정하느냐에 따라서 비용과 얻을 수 있는 수익과 비용이 달라짐을 고려하였다. 본 연구의 모델은 기업의 수익을 최대화하는 것을 목표로 하며, 다른 방식을 활용한 분해계획과의 비교를 통해 유효성을 입증하였다.Companies must strive not only to make profits but also to prevent and improve environment. Therefore, it is necessary not only to simply produce and sell products, but also to consider deeply the post-disposal stage. Recycling products after the disposal provides great effects in terms of economy and environment, and the process of disassembly is essential to do recycling. Therefore, it is important to establish an efficient and economical disassembly plan, which is the core of research on disassembly. In the framework of selective disassembly based on inspection, this study proposes an optimization model that simultaneously determines how to organize the disassembly process for each line and which line to disassemble for each group of EOL products. This is different from previous studies in that it is a disassembly plan that considers both product and line aspects. Since the condition of the EOL product varies depending on the environment in which the product was operated, the target component is determined through inspection rather than pre-determined, and the method of this inspection can be divided into pre-disassembly and post-disassembly inspection. In addition, it is considered that the revenue and cost would vary depending on the setting of the disassembly line. The model of this study aims to maximize net profits and validated its effectiveness through comparison with disassembly plans using other methods제 1 장 서론 1 제 2 장 선행연구 7 2.1 분해에 관한 전반적인 연구 7 2.2 설계 단계에서의 연구: Design for disassembly 7 2.3 사용 이후 단계에서의 연구 9 2.3.1 분해 planning 9 2.3.2 분해 scheduling 10 2.4 연구 의의 11 제 3 장 모델 13 3.1 연구 프레임워크 및 문제상황 13 3.2 목표부품모음, 분해작업목록 생성 15 3.2.1 부품 분류 16 3.2.2 목표부품모음(TCS, target component set) 생성 18 3.2.3 분해작업목록(DTS, disassembly task set) 생성 18 3.2.4 최종 목표부품모음(FTCS), 분해작업목록(FDTS) 생성 19 3.3 수리적 모형 21 3.3.1 Notation 21 3.3.2 목적함수 22 3.3.3 제약조건 24 제 4 장 사례 연구 25 4.1. 부품 분류 25 4.2. 초기 목표부품모음(TCS) 생성 27 4.3. 초기 분해작업목록(DTS 생성 28 4.4. 최종 목표부품모음(TCS), 분해작업목록(DTS) 생성 30 4.5. 사례연구 결과 33 4.6. 유효성 입증 34 4.6.1 유효성 평가 대안 34 4.6.2 유효성 평가 결과 35 제 5 장 결론 및 향후 연구 방향 37 5.1. 결론 37 5.2. 한계점 및 향후 연구 방향 38 참고문헌 40 Abstract 45석

Modeling and Optimization of Disassembly Systems with a High Variety of End of Life States.

Remanufacturing is a promising product recovery method that brings new life to cores that otherwise would be discarded thus losing all value. Disassembly is a sub-process of remanufacturing where components and modules are removed from the core, sorted and graded, and directly reused, refurbished, recycled, or disposed of. Disassembly is the backbone of the remanufacturing process because this is where the reuse value of components and modules is realized. Disassembly is a process that is also very difficult in most instances because it is a mostly manual process creating stochastic removal times of components. There is a high variety of EOL states a core can be in when disassembled and an economic downside due to not all components having reuse potential. This thesis focuses on addressing these difficulties of disassembly in the areas of sequence generation, line balancing, and throughput modeling. In Chapter 2, we develop a series of sequence generation models that considers the material properties, partial disassembly, and sequence dependent task times to determine the optimal order of disassembly in the presence of a high variety of EOL states. In Chapter 3, we develop a joint precedence graph method for disassembly that models all possible EOL states a core can be in that can be used with a wide variety of line balancing algorithms. We also develop a stochastic joint precedence graph method in the situation where some removal times of components are normal random variables. In Chapter 4, we further advance the analytical modeling framework to analyze transfer lines that perform routing logics that result from a high variety of EOL states, such as a restrictive split routing logic and the possibility that disassembly and split operations can be performed at the same workstation.PhDIndustrial and Operations EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111570/1/robriggs_1.pd