Disassembly Efficiency Research Articles

Robotic disassembly re-planning using a two-pointer detection strategy and a super-fast bees algorithm

Abstract Automated disassembly of End-of-Life (EoL) products can be difficult to implement due to uncertainties in their conditions. An automatic re-planning function is required to enable flexible adjustments of disassembly plans and thus increase disassembly efficiency. The re-planning function is able to detect subassemblies and separable components, and adjust disassembly sequences and directions when components interlock and are irremovable. This paper presents a two-pointer detection strategy to find detachable subassemblies very quickly. A summation operator and a list with two pointers are used to check the interferences between components in a minimum number of steps. Then, a ternary bees algorithm is proposed to identify new disassembly sequences and directions. The algorithm combines the merits of a greedy search and meta-heuristic techniques by using only three collaborative potential solutions and three concurrent operations. Experimental results show that the proposed approach is able to perform a rapid subassembly detection and sequence optimisation for a robotic disassembly task, thus allowing real-time re-planning.

Modeling and Planning for Dual-Objective Selective Disassembly Using and/or Graph and Discrete Artificial Bee Colony

Disassembly sequencing is important for remanufacturing and recycling used or discarded products. AND / OR graphs (AOGs) have been applied to describe practical disassembly problems by using “ AND ” and “ OR ” nodes. An AOG-based disassembly sequence planning problem is an NP-hard combinatorial optimization problem. Heuristic evolution methods can be adopted to handle it. While precedence and “ AND ” relationship issues can be addressed, OR (exclusive OR ) relations are not well addressed by the existing heuristic methods. Thus, an ineffective result may be obtained in practice. A conflict matrix is introduced to cope with the exclusive OR relation in an AOG graph. By using it together with precedence and succession matrices in the existing work, this work proposes an effective triple-phase adjustment method to produce feasible disassembly sequences based on an AOG graph. Energy consumption is adopted to evaluate the disassembly efficiency. Its use with the traditional economical criterion leads to a novel dual-objective optimization model such that disassembly profit is maximized and disassembly energy consumption is minimized. An improved artificial bee colony algorithm is developed to effectively generate a set of Pareto solutions for this dual-objective disassembly optimization problem. This methodology is employed to practical disassembly processes of two products to verify its feasibility and effectiveness. The results show that it is capable of rapidly generating satisfactory Pareto results and outperforms a well-known genetic algorithm.

Lexicographic Multiobjective Scatter Search for the Optimization of Sequence-Dependent Selective Disassembly Subject to Multiresource Constraints.

Industrial products' reuse, recovery, and recycling are very important because of their environmental and economic benefits. Effective product disassembly planning methods can improve their recovery efficiency and reduce their bad environmental impact. However, the existing approaches pay little attention to sequence-dependent disassembly with resource constraints, such as limited disassembly operators and tools, which makes the current planning methods ineffective in practice. This paper considers a multiobjective resource-constrained and sequence-dependent disassembly optimization problem with disassembly precedence constraints. Energy consumption is adopted to evaluate the disassembly efficiency. Its use with traditional optimization criterion leads to a novel multiobjective optimization model such that the energy consumption and disassembly time are minimized while disassembly profit is maximized. Since the problem complexity increases with the number of components in a product, a lexicographic multiobjective scatter search (SS) method is proposed to solve the proposed multiobjective optimization problem. Its effectiveness is verified by comparing the results of linear weight SS and genetic algorithms. The results show that it is able to provide a better solution in a short execution time and fulfills the precedence requirement in a product structure and resource constraints.

Modeling and optimization of multi-objective partial disassembly line balancing problem considering hazard and profit

With the improvement of environmental awareness, green manufacturing has been highly concerned by manufacturers and environmental organizations. In particular, for the increasing number of waste electrical and electronic equipment, disassembly as an important content of green manufacturing can reduce environmental impacts and save natural resources. The traditional complete disassembly mode only focuses on disassembly efficiency, which cannot satisfy the needs of environmental protection and economic development. Therefore, this paper establishes an evaluation system of partial disassembly line to balance environmental impacts and economic benefits. In this model, all hazardous tasks must be disassembled, and the benefit indicators of disassembly lines, including the number of workstations, workload smoothness and disassembly profit, are optimized simultaneously. To obtain satisfactory disassembly schemes, a new multi-objective genetic simulated annealing algorithm is proposed. The effectiveness and superiority of the proposed method are verified by a series of test examples. Moreover, a variety of disassembly schemes are presented in a practical disassembly case. All the schemes implement the disassembly of all hazardous tasks, while the average disassembly profit of the proposed method is 23.93%, 9.14% and 15.57% higher than that of other three comparison methods. Experimental results show that the proposed mode and method can not only reduce the environmental impacts, but also improve the economic efficiency indicators of disassembly lines.

An Energy-Saving Optimization Method of Dynamic Scheduling for Disassembly Line

Concerns have been increasing regarding the environmental sustainability of disassembly activities that take place in various recovery operations at end of life stage of products, and subsequently, disassembly activities have been gaining increased exposure. The disassembly line is a good choice for automated disassembly of end-of-life products. Although interest in addressing energy saving in manufacturing is rising, the study of incorporating energy consumption reduction and disassembly efficiency improvement into disassembly line balancing is still limited. The analysis, design, and balanced decision-making for disassembly lines are urgently needed in order to make the disassembly line as energy-saving as possible. In this paper, an energy-saving optimization method, which was used in scheduling workstation selection and the disassembly sequence for the disassembly line, is proposed. Energy consumption of each stage of the disassembling process was analyzed and modeled. Then, a mathematical model of the disassembly line balancing problem with energy saving considerations was formulated and the objective of energy consumption was integrated into the objectives of cost and working load in order to balance a disassembly line. Optimal solutions for the disassembly line balancing problem with an energy saving consideration were obtained by using an artificial bee colony algorithm, which was a feasible way of minimizing workstations, and ensuring similar working load, as well as minimizing energy consumption. Finally, a case study of disassembly line balancing for a typical driving system is presented to illustrate the proposed method.

Robotic disassembly sequence planning using enhanced discrete bees algorithm in remanufacturing

Increasing attention is being paid to remanufacturing due to environmental protection and resource saving. Disassembly, as an essential step of remanufacturing, is always manually finished which is time-consuming while robotic disassembly can improve disassembly efficiency. Before the execution of disassembly, generating optimal disassembly sequence plays a vital role in improving disassembly efficiency. In this paper, to minimise the total disassembly time, an enhanced discrete Bees algorithm (EDBA) is proposed to solve robotic disassembly sequence planning (RDSP) problem. Firstly, the modified feasible solution generation (MFSG) method is used to build the disassembly model. After that, the evaluation criterions for RDSP are proposed to describe the total disassembly time of a disassembly sequence. Then, with the help of mutation operator, EDBA is proposed to determine the optimal disassembly sequence of RDSP. Finally, case studies based on two gear pumps are used to verify the effectiveness of the proposed method. The performance of EDBA is analysed under different parameters and compared with existing optimisation algorithms used in disassembly sequence planning (DSP). The result shows the proposed method is more suitable for robotic disassembly than the traditional method and EDBA generates better quality of solutions compared with the other optimisation algorithms.

An Entropy-Based Adaptive Hybrid Particle Swarm Optimization for Disassembly Line Balancing Problems

In order to improve the product disassembly efficiency, the disassembly line balancing problem (DLBP) is transformed into a problem of searching for the optimum path in the directed and weighted graph by constructing the disassembly hierarchy information graph (DHIG). Then, combining the characteristic of the disassembly sequence, an entropy-based adaptive hybrid particle swarm optimization algorithm (AHPSO) is presented. In this algorithm, entropy is introduced to measure the changing tendency of population diversity, and the dimension learning, crossover and mutation operator are used to increase the probability of producing feasible disassembly solutions (FDS). Performance of the proposed methodology is tested on the primary problem instances available in the literature, and the results are compared with other evolutionary algorithms. The results show that the proposed algorithm is efficient to solve the complex DLBP.

A BIM-based framework for lift planning in topsides disassembly of offshore oil and gas platforms

Abstract Offshore oil and gas platforms (OOGPs) usually have a lifetime of 30–40 years. An increasing number of OOGPs across the world will be retired and decommissioned in the coming decade. Therefore, a safe and efficient approach in planning the disassembly of the topsides of OOGPs is required. One commonly applied disassembly method is reverse installation, which moves the OOGP modules from the platform deck to a heavy lift vessel (HLV) in reverse order of their installation. Considering the high risk and cost of working offshore, shortening the lift time is crucial. In contrast to the traditional experience-driven lift operations, this paper describes minimizing the lift path for each OOGP module during disassembly, leveraging building information modeling (BIM) technology and an improved A* algorithm. BIM models provide accurate component-based geometric and semantic information that can be used for planning and optimization. However, there has been no previous study on the use of BIM for offshore disassembly. Industry Foundation Classes (IFC), which is a neutral data model of BIM, is used in this study to represent OOGP models. In particular, the IfcBuildingElementProxy entity is used to represent the OOGP components, and the information in IfcBuildingElementProxy is automatically extracted to obtain the location and dimension information of each OOGP module. Then, for a given layout of modules on the removal vessel, the lift path and removal sequence of different modules, with the shortest lift path distance, are obtained. The lift path distance is calculated using the A* algorithm, which has been widely applied in 2D environments and is modified in this study to suit the 3D environment. Finally, the genetic algorithm (GA) technique is applied to optimize the layout plan on the removal vessel by minimizing the total lift path distance. The developed BIM-based framework is illustrated and evaluated through an illustrative example. The results show that the proposed framework can generate and visualize the shortest lift path for each OOGP module directly and automatically, and significantly improve the efficiency of OOGP disassembly.

Eco-modular product architecture identification and assessment for product recovery

In order to improve the efficiency of disassembly and product recovery of an abandoned product at the end-of-life stage, it is essential to develop modular product architecture by considering manufacturing and recovering processes in early product design stage. In this paper, a novel concept of a design methodology is introduced to develop eco-modular product architecture and assess the modularity of the architecture from the viewpoint of product recovery. Eco-modular product architecture contributes to enhancing product recovery processes by recycling and reusing modules without full disassembly at component or material levels. It leads to less consumption of natural resources and less landfill damage to the environment. Three sustainable modular drivers, namely, interface complexity, material similarity, and lifespan similarity, are introduced to reconstruct the modular architecture of commercial products into the eco-modular architecture. Alternatives of modular architectures are identified by Markov Cluster Algorithm based on these sustainable modular drivers and physical interconnections of the components of product architecture. To select the eco-modular architecture from these alternatives, we propose modularity assessment metrics to identify independent interactions between modules and the degrees of similarity within each module. To demonstrate the effectiveness of the proposed methodology, a case study is performed with a coffee maker.

Tethering of SCFDia2 to the Replisome Promotes Efficient Ubiquitylation and Disassembly of the CMG Helicase

SummaryDisassembly of the Cdc45-MCM-GINS (CMG) DNA helicase, which unwinds the parental DNA duplex at eukaryotic replication forks, is the key regulated step during replication termination but is poorly understood [1, 2]. In budding yeast, the F-box protein Dia2 drives ubiquitylation of the CMG helicase at the end of replication, leading to a disassembly pathway that requires the Cdc48 segregase [3]. The substrate-binding domain of Dia2 comprises leucine-rich repeats, but Dia2 also has a TPR domain at its amino terminus that interacts with the Ctf4 and Mrc1 subunits of the replisome progression complex [4, 5], which assembles around the CMG helicase at replication forks [6]. Previous studies suggested two disparate roles for the TPR domain of Dia2, either mediating replisome-specific degradation of Mrc1 and Ctf4 [4] or else tethering SCFDia2 (SCF [Skp1/cullin/F-box protein]) to the replisome to increase its local concentration at replication forks [5]. Here, we show that SCFDia2 does not mediate replisome-specific degradation of Mrc1 and Ctf4, either during normal S phase or in response to replication stress. Instead, the tethering of SCFDia2 to the replisome progression complex increases the efficiency of ubiquitylation of the Mcm7 subunit of CMG, both in vitro and in vivo. Correspondingly, loss of tethering reduces the efficiency of CMG disassembly in vivo and is synthetic lethal in combination with a disassembly-defective allele of CDC48. Residual ubiquitylation of Mcm7 in dia2-ΔTPR cells is still CMG specific, highlighting the complex regulation of the final stages of chromosome replication, about which much still remains to be learned.

Disassembly sequence planning for electro-mechanical products under a partial destructive mode

Purpose – To improve the efficiency and economy of electro-mechanical product's recycle process, this paper aims to propose a disassembly sequence planning (DSP) method to reduce additional efforts of removing extra parts in selectable disassembly. Design/methodology/approach – The methodology has three parts, which includes a disassembly hybrid graphic model to describe the product disassembly information, an object inverse-directed method to optimize the disassembly design and a model reconstruction method to achieve a better DSP. Findings – According to the disassembly cost criteria and the parameters of disassembly tools, the disassembly efficiency increases and the disassembly cost decreases due to the use of partial destructive mode compared with non-destructive mode. The proposed partial destructive DSP is more efficient and economical. Research limitations/implications – Partial destructive disassembly mode cannot be used for the flammable or explosive component in the procedure of the DSP optimization algorithm. Practical implications – DSP of an electric corkscrew is analyzed to investigate the accuracy and efficiency of the proposed method. Originality/value – This paper proposes a partial destructive disassembly based DSP method for product disassembly, which provides a new approach for the disposal of end-of-life products.

Design for Disassembly for Remanufacturing: Methodology and Technology

Remanufacturing has become a major aspect of life cycle engineering. Methodologies have been proposed on the optimal ways to disassemble a product in terms of sequence planning and hierarchical modular modelling. New technologies, e.g., the use of smart materials, have enabled fasteners to be removed simultaneously, improving the disassembly efficiency. This paper reviews the advantages, limitations and applications of these methodologies and technologies which can be incorporated at the beginning of the product design stage to facilitate disassembly. A conceptual framework will be discussed to illustrate the integration of methodology, technology and human factors to further enhance the disassembly process.

Electronic Waste Disassembly with Industrial Waste Heat

Waste printed circuit boards (WPCBs) are resource-rich but hazardous, demanding innovative strategies for post-consumer collection, recycling, and mining for economically precious constituents. A novel technology for disassembling electronic components from WPCBs is proposed, using hot air to melt solders and to separate the components and base boards. An automatic heated-air disassembling equipment was designed to operate at a heating source temperature at a maximum of 260 °C and an inlet pressure of 0.5 MPa. A total of 13 individual WPCBs were subjected to disassembling tests at different preheat temperatures in increments of 20 °C between 80 and 160 °C, heating source temperatures ranging from 220 to 300 °C in increments of 20 °C, and incubation periods of 1, 2, 4, 6, or 8 min. For each experimental treatment, the disassembly efficiency was calculated as the ratio of electronic components released from the board to the total number of its original components. The optimal preheat temperature, heating source temperature, and incubation period to disassemble intact components were 120 °C, 260 °C, and 2 min, respectively. The disassembly rate of small surface mount components (side length ≤ 3 mm) was 40-50% lower than that of other surface mount components and pin through hole components. On the basis of these results, a reproducible and sustainable industrial ecological protocol using steam produced by industrial exhaust heat coupled to electronic-waste recycling is proposed, providing an efficient, promising, and green method for both electronic component recovery and industrial exhaust heat reutilization.

Prefabricated Buildings Selective Disassembly Strategy

The assembly building is sought after by people For its speed, subject to the constraints of climate conditions, seismic energy saving and environmental protection, construction of low cost, flexible and diverse housing. However, in the assembly building maintenance, scrap processing and recycling of how to improve the efficiency of demolition is a new issue to be resolved. In this paper, based on the components of the demolition wave optional disassembly planning algorithm, by the definition of prefabricated building demolition wave is a topological relationship of certain components in the assembly building to reflect the components of the demolition order. The calculation of the algorithm is small, easy to use it to carry out efficient search, optional optimal component disassembly sequence, and thus improve the efficiency of disassembly.

Design methodology for active disassembly based on the decapitated head method

Due to the characteristic that shape memory materials can quickly return to their original shape and have large deformation, such materials can be used as the connection in active disassembly devices. However, existing active disassembly devices typically require two moulding steps and complicated machining processes that result in high manufacturing cost. The active disassembly device based on the proposed decapitated head method has only one moulding step and lower manufacturing cost. Its disassembly mode is local damage disassembly, which can decrease the active disassembly cost and improve disassembly efficiency. This paper describes the active disassembly theory and the design methodology based on the decapitated head method, and then analyses the design criteria and feasibility of this method with a real case study.

Selective Disassembly Strategy Based on the CAD Model Assembly Building

The assembly building is sought after by people For its speed, subject to the constraints of climate conditions, seismic energy saving and environmental protection, construction of low cost, flexible and diverse housing. However, in the assembly building maintenance, scrap processing and recycling of how to improve the efficiency of demolition is a new issue to be resolved. In this paper, based on the components of the demolition wave optional disassembly planning algorithm, by the definition of prefabricated building demolition wave is a topological relationship of certain components in the assembly building to reflect the components of the demolition order. The calculation of the algorithm is small, easy to use it to carry out efficient search, optional optimal component disassembly sequence, and thus improve the efficiency of disassembly.

Product Improvement Design Method Facing Modularization Disassembly

From the perspectives of modularization disassembly, the influence of entity structure, function, motion and other factors of product brought to disassembly efficiency is elaborated. A way to improve design facing modularization disassembly is proposed. The time and cost of disassembly are checked by the proposed method through examples. Comparisons of disassembly evaluation before and after improvement are conducted based on the results. The general method to improve design is summarized. In terms of differences of repair probability of key parts in maintenance process, the improvement design criterion is put forward in the method, which improves the maintenance efficiency, reduces the maintenance cost and difficulty of disassembling operation and avoids data explosion of disassembly sequence because of too many parts.

Research on Multi-Step Active Disassembly Method of Products Based on ADSM

The electronic products continue to upgrade at present, how to recycle the discarded electronic products is one of the key research of green design. The method of active disassembly using smart material (ADSM) has acquired widespread concerns. For some products, there is a long distance between the internal active disassembly structure and shell, it needs a long time to reach to the stimulation temperature of internal active disassembly structure, and therefore, it is difficult to completely disassemble these discarded electric products by one step. Moreover, it is not conducive to recycling the material if the components and parts of the disassembly products are mixed together, and the efficiency of disassembly is very low. This paper puts forward multi-step active disassembly method of products, it gives specific procedures of classifying steps according to the principle of division, and it proves the feasibility and superiority of the multi-step active disassembly method of products by referring to mobile model.

Experiments on Reuse-oriented Disassembly of Components from Printed Circuit Boards

In order to realize reuse-oriented disassembly of components from printed circuit boards(PCB) and develop PCB disassembly process and apparatus,it is necessary to analyze and evaluate the influences of various parameters on reusability and disassembly efficiency of components. Mainboards of scraped computers are taken as samples,experiments are performed with three kinds of removal forces and four kinds of heating parameters on a pilot disassembly apparatus under the conditions of hot air heating,and the disassembly efficiency of components is analyzed and the disassembled components are evaluated for reuse. The experiments show that it has a high components disassembly ratio (CDR) for SMDs and THDs with unclinched pins under three kinds of removal forces (contact impact,non-contact impact and vibration). To improve the components disassembly ratio of waste PCBs,the disassembly ratio of slot and connectors should be concentrated on. To improve the reusability ratio of disassembled components,the reusability of IC chips with more than 100 pins should be regarded mainly. In addition,the optimal level range of heating parameters is analyzed with the purpose of better disassembly ratio. The results also show that small impact potential energy is favorable to a high reusability. These experiments provide the basis for determining the reuse-oriented disassembly process of components and also for developing the disassembly apparatus.

Quantitative Evaluation Method of Product Disassembly Based on Parts Failure Rate and Disassembly Time

In view of the fact that product disassembly efficiency is not taken into consideration in the traditional method based on experts' experience,a new quantitative evaluation method of product disassembly is herein presented based on parts failure rate and its disassembly time.Product information model with respect to its disassembly constraint graph is established on the basis of graph theory thought and object-oriented technology.Through developing the procedures of product disassembly sequence generation and optimization,parts disassembly process is simulated and a method of determining the basic disassembly time of product parts is proposed on the basis of modular arrangement of predetermined time standard(MODAPTS).By introducing part failure rate weight,basic disassembly time is converted to relative disassembly time and a calculation model of product disassembly efficiency is established on the basis of parts failure rate and its disassembly time so that the quantitative analysis and evaluation of product disassembly is implemented.The calculation method and its evaluation steps of product disassembly efficiency are demonstrated by combining with one example.Furthermore,the example shows that this quantitative evaluation method is reasonable,feasible,and able to optimize product disassembly design,thus having good engineering application value.