Disassembly Tool Research Articles

An Optimized Advantage Actor-Critic Algorithm for Disassembly Line Balancing Problem Considering Disassembly Tool Degradation

The growing emphasis on ecological preservation and natural resource conservation has significantly advanced resource recycling, facilitating the realization of a sustainable green economy. Essential to resource recycling is the pivotal stage of disassembly, wherein the efficacy of disassembly tools plays a critical role. This work investigates the impact of disassembly tools on disassembly duration and formulates a mathematical model aimed at minimizing workstation cycle time. To solve this model, we employ an optimized advantage actor-critic algorithm within reinforcement learning. Furthermore, it utilizes the CPLEX solver to validate the model’s accuracy. The experimental results obtained from CPLEX not only confirm the algorithm’s viability but also enable a comparative analysis against both the original advantage actor-critic algorithm and the actor-critic algorithm. This comparative work verifies the superiority of the proposed algorithm.

Disassembly Sequence Planning for Intelligent Manufacturing Using Social Engineering Optimizer

Product disassembly and recycling are important issues in green design. Disassembly sequence planning (DSP) is an important problem in the product disassembly process. The core idea is to generate the best or approximately optimal disassembly sequence to reduce disassembly costs and time. According to the characteristics of the DSP problem, a new algorithm to solve the DSP problem is proposed. Firstly, a disassembly hybrid graph is introduced, and a disassembly constraint matrix is established. Secondly, the disassembling time, replacement frequency of disassembly tool and replacement frequency of disassembly direction are taken as evaluation criteria to establish the product fitness function. Then, an improved social engineering optimizer (SEO) method is proposed. In order to enable the algorithm to solve the problem of disassembly sequence planning, a swap operator and swap sequence are introduced, and steps of the social engineering optimizer are redefined. Finally, taking a worm reducer as an example, the proposed algorithm is used to generate the disassembly sequence, and the influence of the parameters on the optimization results is analyzed. Compared with several heuristic intelligent optimization methods, the effectiveness of the proposed method is verified.

Parallel disassembly sequence planning using improved ant colony algorithm

Disassembly is one of the most crucial links in the product life cycle. Disassembly sequence planning (DSP) is a combination of optimization problem and has been studied by many researchers. Asynchronous parallel disassembly planning (APDP) eliminates the requirement that manipulators must start and stop their tasks in the working process. In this paper, a new asynchronous parallel disassembly sequence planning method is proposed, which to deal with the problems of highly time-dependent on asynchronous parallel disassembly mode. The disassembly time model has been divided into execution time and preparation time. The former represents the time consumes by removing a part, and the latter means the time consumes on the disassembly tool preparation while the disassembly position switch. The disassembly matrix and the disassembly work area collision matrix are also utilized to avoid infeasible sequences. Based on the max-min ant system, a waiting strategy is proposed to solve asynchronous parallel disassembly sequence planning problem. To further shorten disassembly process, a time overlap strategy is developed to take advantage of waiting time. Finally, a bevel gear reducer is utilized as an example to discuss and analysis the value of key parameters, as well as the effectiveness of the algorithm and strategies proposed in the paper.

Big data analysis for the estimation of disassembly time and de-manufacturing activity

Abstract Design for disassembly is a key enabling strategy for the development of new business models based on the Industry 4.0 and circular economy paradigms. This paper attempts to define a method, based on Data Mining, for modelling disassembly data from large amount of records collected through the observation of de-manufacturing activities. The method allows to build a repository to characterize the disassembly time of joining elements (e.g. screws, nuts) considering different features and conditions. The approach was preliminary tested on a sample of 344 records for nuts disassembly retrieved by in-house tests. Disassembly time and corrective factors were assessed including the analysis of probability distribution function and standard deviation for each feature (i.e. disassembly tool).

Time computing technique for wear parts dismantling

In a complex mechanical product, the easy dismantling of wear parts is a main requirement to ensure an efficient design. In fact, the maintenance charge in the preventive or corrective case is remarkably expensive, which needs to anticipate the repair assignment in the design phase. Subsequently, considering the disassembly alan (DP) of wear parts, from the early design phase, is a first step in the implementation of the circular economy concept. In this paper, a new disassembly tool based on the wear parts priority concept is presented. A modular decomposition of the product mockup is firstly presented. Based on an extraction data module, a wear parts identification process is conducted. Then, a feasible DP of different modules, containing the identified wear parts, is generated. An evaluation of the generated DPs is performed based on the total disassembly time. The estimation time of different disassembly operations is obtained from industrial practices. An implementation of the proposed approach is detailed using an industrial gear box containing multiple wear parts. A comparative study with the literature highlighted the efficiency of the proposed approach.

A design for disassembly tool oriented to mechatronic product de-manufacturing and recycling

The easy disassembly of certain product components is a prerequisite to guarantee an efficient recovery of parts and materials. This is one of the first step in the implementation of circular economy business models. Design for Disassembly (DfD) is a particular target design methodology supporting engineers in developing industrial products that can be easily disassembled into single components.The paper presents a method and a software tool for quantitatively assessing the disassemblability and recyclability of mechatronic products. The time-based method has been implemented in a software tool, called LeanDfD, which calculates the best disassembly sequences of target components considering disassembly precedencies, liaisons among components, and specific properties to model the real condition of the product at its End-of-Life (EoL). A dedicated repository has been developed to store and classify standard times and corrective factors of each disassembly liaison and operation. This knowledge feeds the two LeanDfD tool modules: (i) product disassemblability module, which allows to carry out the time-based analysis and to improve the disassemblability performance of target components, and (ii) product recyclability module, which estimates the quantities of materials that could be potentially recycled at the product EoL. The LeanDfD tool functionalities have been defined starting from the means of the user stories and the developed tool framework, data structure, databases and use scenarios are described.A group of designers/engineers used the tool during a re-design project of a washing machine, considering the disassemblability as the main driver. The case study highlights how the proposed DfD method and tool are able to support the implementation of re-design actions for improving product de-manufacturability and EoL performance. The LeanDfD features aid engineers in making a quick and robust assessment of their design choices by considering quantitative disassemblability and recyclability metrics.

Forecasting Real Disassembly Time of Industrial Batteries Based on Virtual MTM-UAS Data

Electric vehicle batteries demonstrate the present and future challenges of disassembly, reuse and recycling and indicate the need for an enhanced life cycle design. Considering the complexity of products like batteries, the recycling process depends on disassembly to optimize output fractions, reduce material depletion and environmental effects to close the life cycle. Furthermore, the design phase determines many future impacts in other life cycle phases. With the help of a newly designed virtual disassembly tool based on the MTM-UAS methods, it is now possible to transfer waste treatment knowledge gained from batteries at the end of their life phase to research and development. Information about disassembly time, material composition of the battery system and recycling quota allow for the discovery of optimisation potentials in the first phase of the battery life cycle.

Generating disassembly tasks for selective disassembly using ontology-based disassembly knowledge representation

PurposeThis paper aims to develop methods for generating disassembly tasks for selective disassembly. The disassembly task contains the disassembly information, namely, disassembly direction, disassembly tool and selective disassembly sequence.Design/methodology/approachOntology is adopted to represent the product, and ontology rules are used to represent the disassembly knowledge. A product ontology model (POM) is introduced on the basis of material, connection matrix and interference matrix. Two types of disassembly knowledge are taken into account, one is the disassembly knowledge of disassembly tool selection and the other is the disassembly knowledge of special connections. Based on the POM and the disassembly knowledge, decision support methods are designed to generate disassembly tasks.FindingsA centrifugal pump is used to demonstrate the proposed methods, and the result shows that the methods work well.Research limitations/implicationsThe methods developed in this study are fundamental approaches. The ontology and the ontology rules can be extended with more disassembly knowledge.Originality/valueThe main contribution of this research is the development of methods for representing disassembly knowledge based on ontology rules and the decision support methods for generating disassembly tasks.

Measurement of interfacial thermal conductance in Lithium ion batteries

Abstract Increasing usage and recent accidents due to Lithium ion (Li-ion) batteries exploding or catching on fire has inspired research on the thermal management of these batteries. In cylindrical 18650 cells, heat generated during the charge/discharge cycle must dissipate to the surrounding through its metallic case due to the poor thermal conductivity of the jelly roll, which is spirally wound with many interfaces between electrodes and the polymeric separator. This work develops a technique to measure the thermal resistance across the case-separator interface, which ultimately limits heat transfer out of the jelly roll. Commercial 18650 batteries are discharged and opened using a battery disassembly tool, and the 25 μm thick separator and the 200 μm thick metallic case are harvested to make samples. A miniaturized version of the conventional reference bar method (ASTM D5470 ) combined with infrared thermal microscopy to map the temperature profile including the interfacial temperature jumps enables measurement of the interfacial thermal conductance across a range of case temperatures and interface pressures. The mean thermal conductance across the case-separator interface is 670 ± 275 W/(m2 K) and no significant temperature or pressure dependence on is observed.

Parallel disassembly sequence planning for complex products based on fuzzy-rough sets

The goal of the parallel disassembly sequence planning (PDSP) is to find an optimal feasible disassembly task sequence with many constraints. Due to the PDSP of complex product is restricted by various factors, the DPSP problem is not easily solved in a general form. In order to reduce the time complexity, this paper presents a PDSP method based on fuzzy-rough sets. Five disassembly factors including assembly constraints factor, disassembly precedence factor, disassembly time factor, disassembly tool factor, and combination type factor are defined and formulated. In light of the characteristics of PDSP, the fuzzy-rough set mapping model of parallel disassembly is constructed. The components to be disassembled are taken as knowledge universe, and disassembly membership function as objection function is defined as the indiscernibility relation. Then, the fuzzy-rough set mapping model of parallel disassembly is adopted to generate the optimum parallel disassembly sequence. Finally, two examples validate the proposed method.

A force sensing tool for disassembly operations

This paper discusses the design and characterization of a prototype disassembly tool that was designed to handle a family of electronic devices whose plastic, cantilever snap-fit covers house AA or AAA batteries. The tool was designed with the ability to release the snap-fit covers and the batteries contained inside. The tool design is based on the use of a force sensing tool tip that utilizes three force sensing resistors (FSRs) for force feedback. Two FSRs were used to measure horizontal forces applied to the tool tip while the third FSR was used to measure forces along a direction normal to the tool tip. The tool tip is used to push and lift up the snap-fit cover as well as the spring-loaded batteries. By using the conductance of the FSR sensors, a linear model of the FSR output was calibrated to the force applied to the FSR. The disassembly tool was mounted on a three-axis translational motion robot, and the robot was programmed to perform disassembly operations. Sensor feedback from the FSRs was used to control the movement of the tool during these operations. The results showed that the robot was able to successfully use the disassembly tool to perform the necessary operations to remove the device's snap-fit cover and batteries. Force readings recorded from the FSRs indicated that the disassembly tool was able to react to force interactions at the disassembly tool tip such as a missing part or misaligned part. The use of FSRs resulted in a low-cost, flexible disassembly tool.

A system for automated disassembly of snap-fit covers

This paper reports on a prototype automated system for the disassembly of batteries from a family of electronic devices whose plastic, snap-fit covers house AA or AAA batteries, such as remote controls and calculators. Included in the development of the prototype system was the design of a disassembly tool that uses three force-sensing resistors to provide force feedback information. A pneumatically actuated vacuum gripper and electromagnet system was also developed for recovering the snap-fit cover and batteries once they were released by the disassembly tool. The disassembly module was mounted on the tool head of a three-axis translational motion robot, and a Visual Basic application was developed to interface and control the robot with a Galil digital motion controller. A model-based computer vision application was also developed in Visual C++ using a Kinect sensor and the Open Source Computer Vision library to identify and localize the electronic device placed on the disassembly robot. Using the information gathered by the model-based computer vision application, the robot was able to use the disassembly tool module to perform the necessary disassembly operations to remove the device’s snap-fit cover and batteries. The design of such a disassembly system could aid the future development of fully autonomous disassembly systems that can handle a broader range of electronic products.

Exploring locked nucleic acids as a bio-inspired materials assembly and disassembly tool

Oligonucleotides hold great promise as a recognition-based biomaterials assembly and disassembly tool. Chemically modified oligonucleotides such as locked nucleic acids (LNA) provide the added advantage of nuclease resistance. In the current study, we focus on programming the assembly and disassembly of LNA-linked colloidal particles as a function of sequence composition. We find that incorporation of LNA residues (∼30%) into either one or both primary hybridization partner strands results in a higher duplex density than for isosequential DNA strands. Mismatched primary hybridization partners with sequence length of 11–15 bases have similar initial primary duplex densities. The displacement of mismatched strands by 15 base-long, perfectly matched competitive target strands, however, does depend on the base length of the original mismatched partner strand. Confocal microscopy confirms that substantial colloidal assembly occurs for both perfectly matched and mismatched LNA sequences that are 9 bases in length. Extensive disassembly for the mismatched case is then triggered through the introduction of 15 base-long competitive target strands. Our work demonstrates that LNA can be used to programmatically assemble and disassemble colloidal particles.

О методах деобфускации программ

This paper describes the work on development of the deobfuscation software. The main target of the developed software is the analysis of the obfuscated malware code. The need of this analysis comes from the obfuscation techniques being widely used for protecting implementations. The regular disassembly tool mostly used by an analyst transforms a binary code in a human-readable form but doesn’t simplify the result or verify its correctness. Earlier for this task it was enough to apply pattern-matching cleanup of the inserted useless garbage code, but nowadays obfuscation techniques are getting more complicated thus requiring more complex methods of code analysis and simplification. As deobfuscation methods require analysis and transformation algorithms similar to those of an optimizing compiler, we have evaluated using LLVM compiler infrastructure as a basis for deobfuscation software. The difference from the compiler is that the deobfuscation algorithms do not have the full information about the program being analyzed, but rather a small part of it. The evaluation results show that using LLVM directly does not remove all the artifacts from the obfuscated code, so to provide the cleaner output it is desirable to develop an independent tool. Nevertheless, using LLVM or similar compiler infrastructure is the feasible approach for developing deobfuscation software.

Construction and Evolution of Disassemblable Structure Unit Map for Products

The disassembly analysis graph model(DAGM) is prerequisite for product disassembliability analysis.When design changes happen,the product's DAGM has to be reconstructed.To realize the rapid reconstruction of DAGM,method of reconstruction and evolution for product disassemblable structure unit map(DSUM) is presented.There are so many kinds of connection structures that the typical connection structure is extracted from the complex mechanical products by disassembliability features to form a disassemblable structure unit(DSU).Based on the graph theory,the disassemblable structure unit graph(DSUG) is built to describe the mating contact and priority relationships among constituting components of the DSU.Furthermore,classifying and coding of connection type,composition and disassembly tool for the DSU is performed to simplify the DSUG and thus to form the DSUM.In addition,DSUM evolution methods such as inheriting,combining and deriving operation are proposed to update the DSUM during the design process.Finally,a case study on the air compressor is used to verify the feasibility of the method.

Effects of mismatches on DNA as an isothermal assembly and disassembly tool

Recently, our group developed an approach to drive disassembly of DNA-linked structures at a fixed temperature by adding soluble secondary targets that competitively displace the shorter, original hybridization partners. Here, instead of relying solely on base length differences between primary and secondary targets to drive isothermal disassembly, we introduce a single base mismatch to further weaken the DNA linkages holding colloidal particles together and promote subsequent disassembly upon the addition of perfectly-matched secondary targets.

Programming the kinetics and extent of colloidal disassembly using a DNA trigger

We present experimental studies of the effects of DNA sequence length and concentration on the kinetics of competitive hybridization events in colloidal suspensions. We quantify both the number of displaced soluble target strands and the extent of disassembly of DNA-linked colloidal micelles or colloidal satellites using flow cytometry. The kinetics of competitive displacement of soluble targets are on the order of minutes whereas disassembly of the colloidal micelles requires several hours and even days. By fitting the data to a first-order equation, we found that the observed replacement rate for the soluble target system depends on target base length differences as well as the concentration of the competitive strands. Our studies illustrate that DNA can be employed as a programmable, isothermal disassembly tool for DNA-linked colloidal particles.

Synchronised Design for X platform for performance measurement on the WWW

This paper is concerned with establishing a synchronised Design for X (DFX) platform for various performance measurement (PM) tools that can be used by a variety of users on the Internet to evaluate various product designs, through the standard web browser. Four assistant facilities are contained in the platform. The first one is used to capture the product-related data. The second offers the user the process improvement information. The third provides measurement information of the interaction between process activities and product elements. The last one is an integrative worksheet displaying performance measurement results. To coordinate various users of the system, issues of synchronisation control and conflict resolution are taken into consideration. Finally, a case study is introduced to see how a Design for Disassembly (DFD) tool can be used in the platform with collaborations among users.

A novel disassembly tool with screwnail endeffectors

One of the most intriguing aspects of disassembly is that of dealing with the products not designed for disassembly. This paper presents a novel disassembly tool, wherein a screwnail is used as an endeffector. It is shown that the screwnail indentation process can well overcome the geometrical uncertainties of the products to be dismantled. A self-connection resulted from the screwnail indentation provides a reliable closure to transmit forces and torques required for various dismantling operations. Some differences between the self-connection and the assembly connection are analyzed in detail. With the screwnail endeffector integrated, a disassembly task is decomposed into a screwnail indentation process, a task execution process, and a separating process. A vivid example is given to illustrate these concepts.