Objective Disassembly Sequence Planning of Used Mobile Phones Based on Improved Hybrid Graph Disassembly Model

To solve the problems of environmental pollution and waste of resources caused by used mobile phones, the study of objective disassembly sequence planning is carried out for used mobile phones. In view of the connection of mobile phone parts with multiple parts and the need to disassemble components, the concepts of containment, exclusion, and components are integrated into the hybrid graph. An improved hybrid graph is proposed and the improved hybrid graph disassembly model suitable for mobile phone disassembly is established. The ant colony algorithm is used to search for the optimal disassembly sequence, with the objective of minimum disassembly time. Finally, the improved hybrid graph disassembly model is applied to obtain the disassembly solution of HUAWEI Honor 6. The experimental results demonstrate that the disassembly sequence generated by the improved hybrid graph disassembly model can describe the actual disassembly process of disassembling components with less disassembly time.

A systematic approach in remanufacturing for high efficiency and low cost: The selective parallel disassembly sequence planning

With the growth of environmental awareness, remanufacturing and sustainable manufacturing have become hot issues. Disassembly is the first step and critical activity in remanufacturing. Traditional disassembly sequence planning (DSP) focusses on sequential disassembly. However, it is inefficient for complicated products because only one manipulator is employed to execute disassembly operations. Thus, this work focusses on parallel DSP (PDSP) and proposes a selective parallel disassembly sequence planning (SPDSP) methodology, which performs disassembly compared to sequential DSP and PDSP. In this paper, a mathematical model is used to describe the constraint and precedence relationships, and a parallel sequence model is designed for parallel disassembly. A novel hybrid genetic algorithm (NHGA) based-multi-objective model of SPDSP is proposed for optimisation. In this model, two indicators are integrated: disassembly time (including basic disassembly time, tool exchange time and direction change time) and disassembly costs. A transmission box is used as an instance, and a comparison with conventional genetic algorithm (GA), simulated annealing (SA) and tabu search (TS) is made to validate the practicality of the proposed methodology.

CAD / CAM Application for the Development of Submerged Pump Maintenance Tools

The design and implementation of maintenance tools is used in CAD / CAM tools, in order to make the necessary improvements in the whole process of disassembly of the equipment in question, and mainly to reduce the process time and eliminate the risk. breaking the most fragile parts of the equipment. The objective of the work is to elaborate the toolkit, to reduce the disassembly time and to eliminate damage to the equipment and its respective trajectories, with which the machine performs the machining of the designed drawing, were applied to the resources through a CNC language. (Computer Numeric Command) on a CNC lathe and a machining center. The elaboration of this project based on a CAD system, in this case Solid Works. The average time for disassembly of the equipment was around 2h, now with the proper use of tools, the same process had a time drop to 40 minutes, seen as a great time saving in the disassembly process.

A Charts-Based Approach to Estimate Disassembly Time: Hypothesis, Model and Validation

The purpose of this research is to present a generic method to estimate product disassembly time at detail stage by utilizing Boothroyd and Dewhurst classification form. Disassembly time is critical in decision-making process of end-of-life (EOL) operations, such as reuse, recycling, and remanufacturing. Theoretical assembly time for a design can be estimated using well-established Boothroyd and Dewhurst's method, given an assembly sequence. This method breaks single component assembly time into acquisition time, manual time, and insertion time. However, in disassembly processes, component symmetry features are, in most cases, unnecessary. Based on this fact, a hypothesis is made that a component's disassembly time can be estimated by considering replacing time, part removal time, and elements of surrounding components, including visibility, accessibility, and any additional effort. Fastening component disassembly time can be estimated by replacement time and time consumed by thread number. An assembly model is designed to verify this hypothesis with a predefined disassembly sequence. Totally, 31 undergraduate students took part in the manual assembly and disassembly experiment. Difference between theoretical and manual assembly times was found to be 7.4% while the difference between theoretical and manual disassembly times was 2.4%. Statistical evaluation indicated that the theoretical disassembly time falls within manual disassembly time with 95% confidence interval. To further validate the methods, two case studies are carried out with distinct products under same experimental environment. The approach proposed in this study can estimate disassembly time of a product at detail design stage when disassembly sequence is provided. Future work will focus on automating this method while incorporating selective and destructive disassembly time estimations.

Using Network Analysis and BIM to Quantify the Impact of Design for Disassembly

Design for Disassembly (DfD) is a promising design strategy to improve resource efficiency in buildings. To facilitate its application in design and construction practice, specific assessment tools are currently being developed. By reviewing the literature on DfD, including criteria and assessment methods, and with an explorative research approach on simple examples, we have developed a new method called Disassembly Network Analysis (DNA) to quantify the impact of DfD and link it to specific design improvements. The impact of DfD is measured in material flows generated during the disassembly of a building element. The DNA method uses network analysis and Building Information Modeling to deliver information about flows of recovered and lost materials and disassembly time. This paper presents the DNA method and two illustrative examples. Although DNA is still at a preliminary stage of development, it already shows the potential to compare assemblies and supports better-informed decisions during the design process by detecting potential points of improvements regarding waste generation and time needed to disassemble an element.

Partial/Parallel Disassembly Sequence Planning for Complex Products

Disassembly is a very important step in recycling and maintenance, particularly for energy saving. However, disassembly sequence planning (DSP) is a challenging combinatorial optimization problem due to complex constraints of many products. This paper considers partial and parallel disassembly sequence planning for solving the degrees-of-freedom in modular product design, considering disassembly time, cost, and energy consumption. An automatic self-decomposed disassembly precedence matrix (DPM) is designed to generate partial/parallel disassembly sequence for reducing complexity and improving efficiency. A Tabu search-based hyper heuristic algorithm with exponentially decreasing diversity management strategy is proposed. Compared with the low-level heuristics, the proposed algorithm is more efficient in terms of exploration ability and improving energy benefits (EBs). The comparison results of three different disassembly strategies prove that the partial/parallel disassembly has a great advantage in reducing disassembly time, and improving EBs and disassembly profit (DP).

An interactive system framework to enable design for disassembly

Purpose The purpose of this paper is to present an interactive system to enable product design for disassembly and to offer robust and quick design solutions based on designers’ input. Design/methodology/approach The system utilizes an interactive questionnaire to communicate with the designer. The questionnaire is in the form of binary questions (Yes/No) and design questions that would enable the system to learn the objectives of the design. Solutions are based on a CAD supported design platform. The efficiency of each design is calculated using disassembly time as the metric of measurement using motion-time measurement (MTM). The designer would be able to make an informed decision with respect to component functionality, ease of disassembly and disassembly time. The paper presents a detailed framework and structure of this system. Findings The value of the system is corroborated by means of a case study of an actual product design. The system is structured to offer multiple solutions to a design problem so as to enable the designer to choose the option that best serves their needs. Originality/value This novel interactive system would accept customers’ design preferences as input and offer multiple solutions in order to solve the design problem. Process time is directly calculated using the MTM system of measurement by converting design features into time measurement units. Disassembly time can then be easily converted into disassembly cost by using standard conversion rates. The value to designers is obvious.