Non-destructive Disassembly Research Articles

Experimental investigations of dry-dry timber-concrete composite notched connections designed for disassembly

Timber-Concrete Composite (TCC) decks offer an efficient, and environmentally friendly alternative to conventional concrete slabs. Traditionally the concrete is cast directly onto the timber with a permanent connection arrangement that does not allow non-destructive disassembly at end-of-service-life. This will prevent the reuse of the materials and ultimately decrease the extent of the environmental benefit. This paper presents a deconstructable dry-dry notched connection made from fully prefabricated timber and concrete elements. The concept was investigated through 30 experimental pure-shear push-off tests, where various design parameters, such as prestressing degree, fastener placement, and notch length, were varied. The experimental results indicate that the new connection exhibits the same stiffness characteristics as a traditional wet-dry notched connection. Five different failure modes were observed in the series, and experimental measurements such as Digital Image Correlation and fastener force measurement provided insight into the connection behavior during failure. Two rigid-plastic upper bound solutions were established to estimate the load-carrying capacity for two of the observed concrete failures, and a satisfactory agreement with the test results was obtained. In conclusion, the experimental results indicated that dry-dry notched connections are feasible for achieving a more environmentally friendly TCC structure.

Robotic Disassembly Platform for Disassembly of a Plug-In Hybrid Electric Vehicle Battery: A Case Study

Efficient processing of end-of-life lithium-ion batteries in electric vehicles is an important and pressing challenge in a circular economy. Regardless of whether the processing strategy is recycling, repurposing, or remanufacturing, the first processing step will usually involve disassembly. As battery disassembly is a dangerous task, efforts have been made to robotise it. In this paper, a robotic disassembly platform using four industrial robots is proposed to automate the non-destructive disassembly of a plug-in hybrid electric vehicle battery pack into modules. This work was conducted as a case study to demonstrate the concept of the autonomous disassembly of an electric vehicle battery pack. A two-step object localisation method based on visual information is used to overcome positional uncertainties from different sources and is validated by experiments. Also, the unscrewing system is highlighted, and its functions, such as handling untightened fasteners, loosening jammed screws, and changing the nutrunner adapters with square drives, are detailed. Furthermore, the time required for each operation is compared with that taken by human operators. Finally, the limitations of the platform are reported, and future research directions are suggested.

Non-Destructive Disassembly of Interference Fit under Wear Conditions for Sustainable Remanufacturing

Remanufacturing has been gaining increasing attention in the last few years as a part of green engineering. It is the process of restoring the original specifications of a given product utilizing a combination of new, repaired, and old parts. The present study investigates non-destructive disassembly of an interference fit pin-hub joint to enable the reuse of worn parts with the same loading capacity. The aim is to reduce the disassembly force while preventing plastic deformation and frictional damage on the contact surface to avoid fretting failure and enable further coating. A finite element model of a shaft/hub interference fit was developed, taking into account two cases of damage to the mating parts: deformation and corrosion. The results indicate that thermal disassembly is effective in reducing breaking force by 50% in deformed joints, whereas vibration waves are more suitable for corroded parts with increased friction. In addition, applying a low-frequency oscillation force to the axis of disassembly reduces the pulling out force by 5% and plastic deformation by 99% due to acoustic softening effects. Furthermore, using a heat flux simultaneously with vibration decreases the breaking force by 85%, indicating the higher effectiveness of thermal-aided disassembly and vibration-assisted disassembly in reducing the breaking force of corroded parts with increased friction. This study provides remanufacturing designers with efficient tools to weaken the interference fit and decrease the disconnecting force, ultimately reducing the cost and time required for the disassembly process.

Direct Thermal Management of Windings Enabled by Additive Manufacturing

The electrification and hybridization of ground- and air-transport, in pursuit of Carbon Net Zero targets, is driving demand for high power-density electrical machines. The power-density and reliability of electrical machines is ultimately limited by their ability to dissipate internally generated losses within the temperature constraints of the electrical insulation system. As the electrical windings are typically the dominant source of loss, their enhanced design is in the critical path to improvements in power-density. Application of metal additive manufacturing has the potential to disrupt conventional winding design by removing restrictions on conductor profiles, topologies and embedded thermal management. In this paper, a modular end-winding heat exchanger concept is presented, which enables effective direct cooling without occupying valuable stator slot cross-section. In addition, this arrangement eliminates the need for a good stator-winding thermal interface, thereby allowing mechanical or other less permanent winding retention methods to be used, facilitating non-destructive disassembly and repair. A prototype winding is fabricated and experimentally tested to demonstrate the feasibility of the concept, yielding promising results.

Machine learning based screw drive state detection for unfastening screw connections

The electrification of the transport sector, limited primary materials, and the resulting need for a circular economy drives the automated disassembly of End of Life battery systems. Environmental influences and improper maintenance may cause stripped screw drives. Industrial screw drivers and nut runners evaluate unfastening operations in binary form as OK and NOK (Not OK). However, deeper evaluations such as the detection of stripped screw drives are necessary to decide between destructive and non-destructive disassembly and the resulting tool selection. This paper presents a novel supervised learning based approach for detecting stripped screw drives during the positive locking phase of unfastening operations by using intrinsic data (torque of the screw driver), where the bit or nut are inserted inside the screw drive. The basis of this work is an experimental data set with more than 1,000 unfastening operations from a manual and robot-based test bench, which includes four screw drive types: Torx, Phillips, external hexagon, and internal hexagon. A comparison between multilayer perceptrons (MLPs) and convolutional neural networks (CNNs) have been examined using the experimental data set. Additionally, the reliability and accuracy of the proposed approach have been examined. The findings from this paper demonstrate the feasibility of CNN-based detection for a revolution number lower than one, which is one revolution better than the state of the art techniques, a screw size and screw drive independent detection of stripped screw drives. The CNN model gives an accuracy of 0.98 to predict the screw drive state.

Human–robot collaboration in industrial environments: A literature review on non-destructive disassembly

Nowadays, numerous companies and industries introduce recycling processes in their production, aiming to increase the sustainable use of the planet’s natural resources. Nevertheless, these processes remain inefficient due to the high degree of complexity and variation in the products. In order to remedy this, industry stakeholders adopt the circular economy business model and introduce take-back programmes and remanufacturing processes for their End of Life products in their own supply chains. Take-back programmes enable the re-sourcing of sub-assemblies and components of previously manufactured products while remanufacturing processes encourage non-destructive disassembly. Due to the uncertain conditions of the re-sourced products, fully automated cells cannot cope with the demanding disassembly processes. Therefore, there is a need to establish hybrid disassembly robot cells where humans and robots work closely together in a process known as human–robot collaborative disassembly (HRCD). This paper examines the landscape of HRCD and reviews the progress in the field during the period 2009–2020. The analysis investigates principles and elements of human–robot collaboration in industrial environments such as safety standards and collaborative operation modes, HRI communication interfaces, and the design characteristics of a disassembly process. Additionally, the various technical challenges of HRCD are explored, and a review of existing systems supporting HRCD is presented. This review aims to support the robotics community in the future development of HRCD systems, discuss identified literature gaps, and suggest future research directions in this area. • This paper presents the first extensive review of the latest progress in the area of Industrial human–robot collaboration within the field of disassembly for the period 2009–2020. • The perspective is on how robot control schemes and human–robot interfaces enable human–robot collaborative disassembly tasks. • The outcome of this review identifies gaps in the practice of human–robot collaborative disassembly and provides the future trends and needs for robot cells focused on disassembly tasks.

Screw detection for disassembly of electronic waste using reasoning and re-training of a deep learning model

Growing populations, increasing standards of living, and reliance on advancing technologies are resulting in an emerging abundance of electronic waste. Automating disassembly of these electronic products is a vital part of improving end-of-life product treatment where hazardous chemicals and materials are present. Furthermore, non-destructive disassembly is ideal to preserve the embodied energy in components from manufacturing. This requires the removal, and hence detection, of fasteners like screws in a disassembly environment. Crosshead screws are a common fastener type used in LCD monitors. This paper proposes a method of screw detection for disassembly and presents results of detection of crosshead screws on components of various models of LCD monitors in a disassembly cell. The system first applies gamma correction to standardize brightness––or luminance–– of images. Generic knowledge about screw features in the form of a deep learning model is then used to visually detects screws. The results are analyzed against common screw location combinations on product components in order to logically reason about possible undetected screws that are also likely to exist. Finally, true negative detections are collected as new training data and the deep learning model is re-trained on these missed detections to improve performance; tailoring and adapting to the environment of the specific disassembly cell.

Study on the High-performance Composite Wall Panel Envelop of Building and its Relevant Joint Construction

Aiming at the general problems of envelop wall panel about the existing building, such as large surface density, low strength, poor service performance and high maintenance cost, a kind of high-performance composite wall panel is proposed in this paper. This wall panel takes high toughness cement-based composite material as shell and inorganic light thermal insulation material as core part. Its surface density equals to or is less than 70 kg/m2, heat transfer coefficient equals to or is less than 1 W/ (m2·K ), and the minimum bending failure load equals to or is more than 8 times of wall panel weight. Combined with the characteristics of high-performance composite wall panel, the “removable connection system” and “beveled tongue and groove type” joint structure are proposed to realize the construction of high-performance composite wall panel without moisture, nondestructive free disassembly and green recycling.

Design of assembled substrate of electroplated diamond grinding wheel for disassembly of abrasive layer

Expensive diamond grains remaining within waste diamond grinding wheels and wheel substrate need to be recycled. Electroplated diamond grinding wheel was taken as an example. An idea of “substrate structure-induced cracks (SSIC)” was proposed to solve the disassembly problem of waste electroplated diamond wheels. An assembled substrate for electroplated diamond grinding wheel was designed. Fabrication and disassembly experiments of electroplated diamond wheel with assembled substrate were carried out. Also, finite element analysis was used to investigate the mechanism of disassembly processes. Recycling experiments of electroplated diamond wheels were carried out in three ways, namely acid corrosion method, electrolysis method and SSIC method. The experimental results show that cracks generate in the diamond abrasive layer of the assembled wheel. The simulated maximum principal stress occurs on diamond abrasive layer near the mating surface between cylindrical pins and substrate, which is consistent with the location where the crack is created. The abrasive layer can be easily peeled off from substrate after the cracks occur on abrasive layer. Compared with electrolysis and acid corrosion methods, the SSIC method has the shortest disassembly time and the lowest disassembly costs. The assembled substrate provides possibility to exert cracking forces from substrate to diamond abrasive layer. With assembled substrate, the nondestructive disassembly of electroplated diamond wheel can be fulfilled. Assembled substrate can meet the need of DFD for electroplated diamond grinding wheel.

Nondestructive Surface Threshold Definition for Remanufacturing Disassembly of Interference Fit

The disassembly of interference fit is a difficult process for remanufacturing engineering, which frequently causes multiple types of friction damage, such as scratches, furrow, and adhesion on the surface of parts. The form and size of surface damage directly affect the cost of remanufacturing repair. If the damage is less than a threshold, the part can be directly used for assembly without repairing. This condition represents a nondestructive disassembly, which is the goal of remanufacturing disassembly for interference fit. In this study, varying degrees of disassembly surface damage of interference fit are obtained by experiment and detected by TRIMOS-CL3 3D surface profilometer. Six surface evaluation parameters Sv, Sp, Sq, Str, Vmp, and Sa, are selected from ISO 25178 as indexes for entropy analysis to evaluate the damage comprehensively. According to the interface state, a comprehensive evaluation threshold of nondestructive disassembly is proposed. The rationality of the threshold is verified by the load-carrying capacity experiment of the interference fit.

Application of exergy-based approach for implementing design for reuse: The case of microwave oven

Systematic reuse of parts is not often achievable in a sustainable way. The methods associated with the available disassembly technology rarely addresses non-destructive disassembly approach that favor reuse as an end-of-life (EoL) strategy. In this sense, this paper aims to propose a method able to identify best opportunities and thus, focus on the designers’ efforts during the early stages of product development, with major repercussions during the product EoL. To build the method, the Design Science Research Methodology (DSRM) is adopted. The method scope relies on material and energy flows measured in terms of exergy that ultimately depicts for energy efficiency, environmental impact, cost and technical efficiency. By means of a case study, findings challenge common sense by quantitatively showing how small subsystems with 3% of mass can hold nearly 200 times more embodied exergy than another with 50% of the mass and thus, may greatly affect product design and EoL results. Therefore, the adoption of the method may prove useful for establishing easy-to-use design practices that favor green engineering, circular economy and environmental policies. An exergy-based approach would unbiasedly drive Reuse EoL that facilitate Design for the Environment (DfE) as well as focus efforts on specific disassembly technologies.

Evaluation of Detachable Ga-Based Solder Contacts for Thermoelectric Materials

Low electrical and thermal contact resistances are a prerequisite for highly efficient thermoelectric generators. Likewise, certain measurement setups for characterization of thermoelectric materials rely on good-quality contacts between sample and setup. Detachable contacts are an interesting alternative to permanent contacting solutions due to ease of handling and nondestructive disassembly of valuable samples. Therefore, the applicability of gallium-based liquid metal solder as detachable contact material was studied, particularly with regard to compatibility of the solder with state-of-the-art thermoelectric materials CoSb3, Mg2Si, and FeSi2. Tungsten, nickel, chromium, and titanium were tested as protective coatings between the thermoelectric material and liquid metal solder. Electrical measurements showed that some materials form excellent and stable contacts with the solder for a limited temperature range. At higher temperatures, application of a protective layer was found to be necessary for all investigated materials. Tungsten and nickel showed promising results as protective layer.

Selective Disassembly Planning for the End-of-life Product

Selective disassembly planning searches solutions to separate useful parts of a product to be reused or recycled at the end of the product life. An efficient method is essential for disassembly planning in the product recycling process to reduce the operation time and cost. This paper proposes an efficient method for selective disassembly sequence planning considering destructive operations. Different from the most existing methods that mainly consider the non-destructive disassembly, destructive disassembly operations are considered to improve the product recycling and operation efficiency. An efficient product representation approach and search algorithms are proposed to generate the optimal disassembly sequence plan. Multi-level constraint matrices based on products’ bill of materials are constructed to identify products’ structure to reduce the searching size of disassembly plans. An industrial mechanical arm is used in the case study to verify the proposed method.

A Method for Improving the Process and Cost of Nondestructive Disassembly

The ever-increasing global environmental concerns demand that strong emphasis be given to the decision-making process pertaining to the strategy of design for nondestructive disassembly during the product evaluation stage. The ultimate objective is to considerably increase the percentage of product components and materials suitable for recycling, recovery, and/or reuse. In this context, this paper proposes a method for improving the nondestructive disassembly of a final product. This method analyzes the nondestructive disassembly by determining a disassembly interference matrix, feasible disassembly sequences, and improved nondestructive disassembly sequences. The innovative element of the nondestructive disassembly method proposed in this paper is integrating the generated conceptual design solutions for a given technical device with a software package developed for determining its improved disassembly sequence embedded within a 3D CAD platform. The developed procedure is based on information obtained from a 3D CAD model of a product, such as geometric constraints, automatic identification of fasteners and components, determination of component-to-component and component-to-fastener connection graphs, and AND/OR logic operations. The goal is for product designers to predict, evaluate, and define improved disassembly sequences while minimizing the cost of disassembly operations as early in the design stage as possible after a CAD model of the product becomes available. The applicability of the integrated method for determining the improved disassembly sequence is presented through an illustrative example.

Physics-based virtual reality for task learning and intelligent disassembly planning

Physics-based simulation is increasingly important in virtual manufacturing for product assembly and disassembly operations. This work explores potential benefits of physics-based modeling for automatic learning of assembly tasks and for intelligent disassembly planning in desktop virtual reality. The paper shows how realistic physical animation of manipulation tasks can be exploited for learning sequential constraints from user demonstrations. In particular, a method is proposed where information about physical interaction is used to discover task precedences and to reason about task similarities. A second contribution of the paper is the application of physics-based modeling to the problem of disassembly sequence planning. A novel approach is described to find all physically admissible subassemblies in which a set of rigid objects can be disassembled. Moreover, efficient strategies are presented aimed at reducing the computational time required for automatic disassembly planning. The proposed strategies take into account precedence relations arising from user assembly demonstrations as well as geometrical clustering. A motion planning technique has also been developed to generate non-destructive disassembly paths in a query-based approach. Experiments have been performed in an interactive virtual environment including a dataglove and motion tracker that allows realistic object manipulation and grasping.

A liaison model for disassembly-reassembly product ecodesign

This paper focuses on non-destructive disassembly for mechanical products as part of environment friendly manufacturing. An original approach using a clustering method for assembly and the introduction of a mathematical model, describing the fuzzy liaisons between the components, allow us to design the product for disassembly, service, recycling, upgrading and assembly. They also facilitate the determination of the problems related to the automation of assembly and disassembly sequences generation. To do so, the modelling of functional liaisons between parts helps to distinguish a simple contact from an attachment and subsets from subassemblies. Liaisons between components are described by matrices of fuzzy half degrees of liaison. The virtual locking liaisons could be extracted automatically from a B-rep model of a mechanical product on CAD and attachment liaisons are deduced from a fuzzy evaluation of their strength and condition changes.

Custom-molded ear-plug, and process for producing a custom-molded ear-plug device

A hearing device and process for its updating, including a resilient outer shell and one or more internal units, with the outer shell conforming in shape to at least one of the internal units so that the internal unit is held snugly in place. The outer shell can be replaced using either a destructive or non-destructive disassembly method to re-use at least one of the internal units.

Nondestructive Disassembly System for White Board Marker

The rapidly growing concern about environmental and resource protection have stimulatedmany industrial sectors to solve the disposal problems of used products. The recovery processes canbe simply categorized into material recovery and product/component recovery. Material recoverymostly involves disassembly for separation and processing of materials of used products. Destructive methods such as dismantling, shredding, or chemical operations are normally used. Product recoveryincludes disassembly, cleaning, sorting, replacing or repairing bad components, reconditioning,testing, reassembling and inspecting. These recovered components/products can be reused inrepairing and re-manufacturing. That provides an opportunity in bringing the used products back to an “as new” condition. This paper utilizes the concept of non-destructive method of product recovery processes and develops an automatic disassembly system for white board marker pens. The experimental results show that the cycle time for the disassembly processes is about 3.8 second that is believed to be compatible to the desired feeding rate for manufacturing. In addition, the reused rate for the recovered components is close to 100% except the fiber-refill component.

Disassembly to order system under uncertainty

This paper presents a multi-criteria optimization model of a disassembly-to-order (DTO) system under uncertainty. The goal of the proposed model is to determine the best combination of the number of each product type to be taken back from the last user and/or collectors. The EOL products are then disassembled for the retrieval of reusable components and materials and resold in order to meet a certain level of demand under a variety of physical, financial and environmental constraints. The surplus components are recycled, stored for usage in subsequent periods or properly disposed. The problem is modeled as a multi-criteria decision-making problem under uncertainty, where the aspiration levels for various goals are more likely to be in the “approximately more (less) than” and/or “more (less) is better” form. We employ fuzzy goal programming technique to solve the problem. When solved, the model provides the number of EOL products to be taken back as well as the number of items reused, recycled, stored and disposed. The values of a host of other performance measures are also obtained, including total profit, materials and items sales revenues, take back cost, transportation costs as well as costs of preparation of EOL products, destructive disassembly, non-destructive disassembly, recycling, storage and disposal. A case example is presented to illustrate the model's implementation.

Virtual disassembly of products based on geometric models

This paper describes different aspects of a disassembly system and presents the information model to obtain, on the one hand, the movements necessary for removing a component, and, on the other, a simulation of the disassembly process carried out. The inputs of the disassembly system are the CAD model of the product to be disassembled and the different features of the components stored in a database. Based on such information, an object-oriented model required for developing the disassembly process in a flexible way is generated. Local and global strategies for the removal of one component, using a set of translational movements, are described. Finally, the paper describes a simulation system that allows the verification of the disassembly movements automatically obtained, and simultaneously, to determine the ease of non-destructive disassembly.