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Design for active disassembly (DfAD): an outline for future research
Abstract
Although active disassembly is an expanding research topic, no dedicated methodology for developing joining elements suitable for self-disassembling products has been described yet. Therefore, this paper presents a framework joining vital factors for developing new joining elements to be designed into self-disassembling products. The framework covers issues related to the authorisation level, the flexibility of product structures, the product functionality and the degree of restrictions during the design process.
... • One-to-many techniques: This group allows for obtaining more than one component by performing a single disassembly action. For example, applying a heat source to an assembly body can activate multiple snap-fit mechanisms at once, causing several components to detach simultaneously (Willems et al., 2005). ...
... Disassembly Embedded Design and Active Disassembly methods Chiodo et al., 1998b;Chiodo and Jones, 2012;Sun et al., 2014) are classified as one-to-many techniques (Willems et al., 2005). Disassembly Embedded Design utilizes smart materials or structures in product design to incorporate triggers that enable the disassembly of one or multiple components. ...
... On the other hand, Active Disassembly focuses on designing products that can be disassembled by the application of a trigger. Willems et al. (2005) differentiate embedded and active disassembly based on the trigger principle. Embedded triggers encompass mechanical force, heat-activated mechanisms, and electromagnetic triggers, while active disassembly triggers include pneumatic elements, smart materials, freezing elements, and soluble nuts. ...
... While, one to many disassembly actions involves removal of various connections with one disassembly action. Economic models proved that, one to many disassembly technique reduces disassembly time and cost greatly [10]. ...
... This mechanism can be triggered to initiate the disassembly process using a thermal, electrical, mechanical or an electromagnetic stimuli [9]. While, active disassembly enables separation of assemblies using smart materials or structures in the product that can be activated using a single or more external stimuli [10]. ...
... First, during implementation, the specific nature of disconnection for each product feature, requires a considerable amount of knowledge and time from the designer. Second, the reduction in disassembly time is limited because of the physical constraints that reduces the number of connections that can be linked to be unfastened at the same time with one disassembly action [10]. Third, each embedded device has a unique application feature for each product, as a result they cannot be used in other applications without considerable redesign efforts [11]. ...
The rapid changes in industry during the past decade, have started to greatly affect the manufacturing environment and production facilities. Traditional production facilities are being replaced by smart factories that are based on high technological aspects using smart machines to produce smart products. Due to the shortening of products life cycle, the need for a rapid design process has become an emerging issue.However, the rapid design process is not the only challenge but also, speed and efficiency of the assembly process, after sale services and disassembly operations. Thus, design for disassembly has become an important sub-topic for the design process. As a result, product designers are now concerned with designing products that can be disassembled easily to avoid destructive separation of products, in order to minimize waste and scrap of products at their end of life. This can be done by allowing recovery of reusable components and materials so that they can be used in later generations of products, re-manufacturing or recycling processes.Design for disassembly offers different disassembly techniques that can facilitate the disassembly process greatly. Active disassembly is considered as one of the most important disassembly techniques. This is due to the fact; active disassembly can provide a more generic solution for most of disassembly problems as well be discussed in the present research. As a result, the present research aims to present an overview of design for disassembly discussing its different techniques with emphasis on active disassembly focusing on its importance and advances in detail.
... Prior research has pointed out that substantial time is required to identify and localize every fasteners [40]. Therefore, it was assumed that AD, which eliminates the need of fastener identification and localization, can enable a substantial productivity increase of today's disassembly operations [41]. ...
... Therefore, it was assumed that AD, which eliminates the need of fastener identification and localization, can enable a substantial productivity increase of today's disassembly operations [41]. Moreover, it was predicted that only active disassembly has the potential to shift an EoL treatment with systematic disassembly from a cost factor to a profit generating activity [40,42]. The most extensive research on active disassembly yet is based on shape memory materials [43][44][45][46][47][48][49]. ...
... In collaboration with Philips this shape was further optimized by implementing foil hinges in the snap-fit design, as shown in Figure 14 [90]. Figure 13 Pressure sensitive snap fit developed by B. Willems [8,40] Figure 14 Prototype of pressure sensitive snap-fit embodiment optimized in cooperation with Philips [38] Brown et al. describe in a patent a hook and loop like fastener with the same working principle, in which the different hooks contain cavities in which a pressure can be built up which will cause the hooks to stretch and the fastener to release [91]. ...
This paper presents a number of novel active fasteners
developed to significantly lower disassembly costs during
reconditioning, remanufacturing, and recycling of products.
In the initial stage of the fastener development process,
the applicability of distinct trigger signals for active disassembly
(AD) is evaluated. Based on this evaluation, the high robustness
of using a pressure increase or decrease as a nondestructive
trigger for AD is demonstrated. Since previously
proposed pressure-sensitive fasteners face considerable drawbacks
upon implementation in electronic products due to the
ongoing trend of miniaturization, a second generation of
pressure-based active fasteners is developed. Evaluation of
these fasteners by means of axiomatic design techniques and
prototyping demonstrates that the presented snap-fits, which
make use of a closed-cell elastomer foam, are most robust.
Subsequently, the contraction forces that closed-celled foams
can exert as a function of an increase in ambient air pressure
are experimentally determined. Furthermore, the implementation
of pressure-sensitive foam-based snap-fits in both a modem
and a payment terminal is described. Results of these
experiments demonstrate that the contraction force of a
cross-linked metallocene polyethylene closed-cell foams can
reach up to 6 N/cm2 at an overpressure of 2 bar and that the
foam-based snap-fits can be released at a pressure increase of
2 bar.
... Both manual and automated disassembly methods have the same one-to-one disassembly process. This one-to-one action is described by Willems, Dewulf, and Duflou (2005) as one or more actions will disassemble one component of a product. For example, unscrewing bolts for the housing of an electric motor will only partially disassemble the electric motor. ...
... Other bolts, screws, and snaps must be dealt with to fully disassemble the motor. This one-to-one disassembly process shows the inefficiency in current disassembly methods (manual and automated) and is the main reason why mass shredding or basic disposal is the norm in EoL scenarios (Duflou et al. 2008;Willems, Dewulf, and Duflou 2005). ...
... Since these costs are not explicitly seen, Willems, Dewulf, and Duflou (2005) raises doubt in the actual benefit gained from using AD. ...
... Finally, they focus only on the design of a heat-reversible snap rather than handling the entire assembly, and the locators and snaps as a system to achieve the system level objectives. For more information about different active disassembly methods refer to Willems et al. [75]. The new heat-reversible locator-snap system presented in this research has the following advantages over the current reversible joints presented in this literature review: ...
... Snap-fit is a preferred joining method for DFD for the following reasons [28], [75]- [77]: Early work on integral attachment design focused on the analysis of particular types of locking features such as cantilever hooks [78], bayonet-fingers [79], compressible hooks [80], etc. More recently, Genc et al. [81]- [83] discussed a feature-based method to integral attachment design, which classified snap-fit features into three categories: ...
The use of joints that can disengage with minimum labor, part damage, and material contamination is critical to ensure effective service, part reuse, and material recycling. This dissertation develops a general computational method for designing lock-and-key heat-reversible locator-snap systems that satisfy the aforementioned requirements. The lock-and-key concept is like a security code that allows easy disassembly when the right procedure is followed. It is realized by double-latching snaps that require force within a certain range to disengage, and multiple snaps that require heating multiple locations at different temperatures to disengage. During disassembly, thermal expansion constrained by locators and temperature gradient along the wall thickness are exploited to realize the deformation required to release the snaps.
A generic optimization problem is posed to find the orientations, numbers, and locations of locators and snaps, and the numbers, locations, and sizes of heating areas, which realize the release of snaps with minimum heating and maximum stiffness, while satisfying motion and structural requirements. Screw Theory is utilized to pre-calculate the set of feasible orientations of locators and snaps that are examined during optimization.
Multi-Objective Genetic Algorithm (MOGA) is used for solving the posed generic optimization problem. A parallel version, using manager-worker scheme, with active load balancing is developed to solve the generic optimization problem efficiently. The proposed algorithm selects between two parallelization schemes based on the average objective function evaluation time and either divides the population evenly over all processors or sends small patches of the population to the idle workers.
The proposed heat-reversible locator-snap systems are applied to different case studies ranging from automotive bodies to consumer electronics. The first case study deals with joining internal frames and external panels in automotive bodies. Next, the proposed locator-snap systems are applied to a T-shaped DVD player enclosure, an enclosure model with complex mating line geometry, and a flat panel TV enclosure. In the later, the developed Parallel genetic algorithm is used and its performance is analyzed. In all case studies, the resulting Pareto-optimal solutions result in alternative designs with different trade-offs between the design objectives while satisfying all the constraints.
... DED uses a specialized product design for which a single disassembly field will cause the product to disassemble. The conceptualization of DED has shown further efficiency improvements with disassembly processes, but with its specialized designs, actual implementation of DED has been limited due to the intense design work that must be made to ensure successful product disassembly [3]. Because of the intense design work for DEDs, another one-to-many disassembly methodology has developed, known as active disassembly (AD). ...
... Past AD research has focused on conceptual ideas for special fasteners. Willems, Dewulf et al. [3] presents an overall review of AD concepts for elements that are triggered by thermal, chemical, and pressure fields. Modelling of such concepts has also be prevalent with Willems, Dewulf et al. [4] presenting a pressure triggered AD element that upon changing pressure fields disassembles and separates components from a product assembly. ...
Disassembly is becoming a mandatory step in the end-of-life processing for electronic products. More and more regulations call for the removal of hazardous materials and mandate the recovery of components and recyclable materials. It is then no surprise that research has continually looked for more efficient methods of disassembly. Of these methods, active disassembly is at the forefront. Active disassembly incorporates innovative fasteners, which under a special environmental condition will exhibit a disassembling or releasing action. The use of smart materials, more specifically shape memory alloys and shape memory polymers, has been extensively documented. For shape memory polymers, past research has shown innovative designs, such as thread-losing screws and deformable brackets. What has not been shown with shape memory polymers, however, is one of the most basic and common fasteners-the snap-fit. This paper examines the design and processing method for creating a shape memory polymer snap-fit and demonstrates its effectiveness as an actively disassembling fastener.
... Especially, manual operation in disassembly is often a labor intensive and costly process. Especially, the time to localize and identify fasteners covers approximately 30% of the total disassembly time [2]. ...
... The prior studies have shown that the economic feasibility of disassembly can be guaranteed if such manual disassembling operations are drastically simplified [1,5]. In this direction, active disassembly [2,9] is a developing technology, in which specific external triggers deform fasteners simultaneously and disassemble a product efficiently by using the characteristic of smart materials (e.g., shape memory alloys). ...
This paper proposes a computer-aided design method for semi-destructive disassembly with split lines. This method aims at extracting reusable, recyclable, or hazardous components more efficiently than manual disassembly with higher quality than shredding. The split line is a shape feature of a product that enables to destruct the product into desired shape, like pull tabs of cans. The proposed method aids a designer in adding proper split lines to extract target components. A case study showed that the semi-destructive disassembly sequence of an air conditioner with the split lines reduces the number of steps needed for extracting a target component.
... -Design For Disassembly (DFD), for which many efforts have been made in prior research, since the efficiency of disassembly operations can be significantly influenced by an optimization of the product structure [14]. However, the time to localize and identify connectors covers approximately 30% of the total disassembly time [15]. Furthermore, prior studies have shown that the economic feasibility of disassembly can only be guaranteed if the disassembly time and cost are reduced by at least 75% for electronic products [16]. ...
... Since AD allows simultaneously releasing fasteners within different products, AD is assumed to allow a productivity increase by a factor 5 to 10, and to reduce the disassembly costs with up to 70% [16]. Therefore, active disassembly, when properly implemented, has the potential to shift an EoL treatment with systematic disassembly from a cost factor to a profit generating activity [15,17]. ...
The principle of Active Disassembly (AD), in which innovative reversible fasteners can be simultaneously activated by an external trigger signal, enables a promising End-of-Life (EoL) treatment for electric and electronic products. Therefore, the economic and environmental constraints for implementing AD are discussed, as well as the information requirements for AD. Furthermore, the potential benefits of properly implementing active fasteners in a Liquid Cristal Display (LCD) and a Plasma Display Panel television are presented based on a case study.
... In the original project, students disassembled a small plastic wind-up toy, measured and modeled all the parts, and then created an assembly of those parts in SOLIDWORKS. A portion of class time during this project was devoted to discussing design for disassembly using resources through VentureWell [6] and other resources on design for active disassembly [7]. ...
... These fasteners use the principle of shape memory alloy or shape memory polymer that is highly flexible when triggered by external conditions, such as temperature and pressure (Liu et al., 2010). This concept provides the convenience to disassemble and recycle products at a shorter operation time through modular disassembly processes that are lacking through the conventional disassembly approaches (Duflou et al., 2008;Duflou et al., 2006;Willems et al., 2005). ...
Stricter vehicle emission legislation has driven significant reduction in environmental impact of the vehicle use phase through increasing use of lightweight materials and multi-material concepts to reduce the vehicle mass. The joining techniques used for joining multi-material designs has led to reduction in efficiency of the current shredder-based recycling practices. This thesis quantifies this reduction in efficiency using data captured from industrial recycling trials. Life Cycle Assessment has been widely used to assess the environmental impact throughout the vehicle life cycle stages. Although there is significant research on material selection or substitution to improve the vehicle’s carbon footprint, the correlation between multi-material vehicle designs and the material separation through commonly used shredding process is not well captured in the current analysis. This thesis addresses this gap using data captured from industrial trials to measure the influence of different joining techniques on material recycling efficiencies. The effects of material degradation due to joining choices are examined using the life cycle analysis including exergy losses to account for a closed-loop system. The System Dynamics approach is then performed to demonstrate the dynamic life cycle impact of joining choices used for new multi-material vehicle designs. Observations from the case studies conducted in Australia and Europe showed that mechanical fasteners, particularly machine screws, are increasingly used to join different material types and are less likely to be perfectly liberated during the shredding process. The characteristics of joints, such as joint strength, material type, size, diameter, location, temperature resistance, protrusion level, and surface smoothness, have an influence on the material liberation in the current sorting practices. Additionally, the liberation of joints is also affected by the density and thickness of materials being joined. The life cycle analysis including exergy losses shows a significant environmental burden caused by the amount of impurities and valuable material losses due to unliberated joints. By measuring the influence of joints quantitatively, this work has looked at the potential of improving the quality of materials recycled from ELV to be reused in a closed-loop system. The dynamic behaviours between the joining choices and their delayed influence on material recycling efficiencies from the life cycle perspective are performed using the data from case studies. It shows that the short-term reduction in environmental impact through multi-material structures is offset over the long-term by the increasing impurities and valuable material losses due to unliberated joints. The different vehicle recycling systems can then be resembled using two widely known system archetypes: “Fixes that Fail” and “Shifting the Burden”. Despite the adoption of more rigorous recycling approaches, the life cycle impact of different joining techniques on vehicle recycling continue to exist. The enactment of strict regulations in current ELV recycling systems is unable to solve the underlying ELV waste problem, and only prolongs the delay in material degradation due to joining choices. This work shows that the choice of joining techniques used for multi-material vehicle designs has a significant impact on the environmental performance during the ELV recycling phase.
... However, prior studies have shown that the cost of EoL treatment heavily depends on the time required to disassemble a product [4]. The economic feasibility of disassembly can only be guaranteed if such manual operations are drastically simplified in modern EoL process [5] [6]. Therefore, numerous efforts have been made on the research on Design for Disassembly (DfD) [4] [7][8] [9] to improve the ability of products to be disassembled at the design stage. ...
Disassembly is a fundamental process for component reuse, remanufacturing, and material recycling of all assembled products. In the last decades, design methodologies for disassembly that simplify products’ structure, fastener, and disassembling process have been widely explored. However, the shape of components to be recycled or discarded need not be maintained in the end-of-life process. This means that we can separate valuable and/or hazardous components more rapidly by deforming or breaking surrounding components designed for the deformation or destruction process. This article proposes a computer-aided design method for such semi-destructive disassembly. In the detailed design phase of the method, linear shape features that enable to break a product into desired shape of chunks are added to the product geometric model. The semi-destructive process aims at extracting reusable, recyclable, or hazardous components more efficiently than manual disassembly with higher quality than shredding. The system supports a designer in determining the location of the linear features called split lines.
... Design for active disassembly requires the implementation of active fasteners which can be simultaneously unfastened without direct, individual, physical contact between a disassembly tool and every individual fastener (Duflou et al., 2008). The presented case study focus on the evaluation of active fasteners, since prior research predicted that active disassembly has the potential to shift an EoL treatment with systematic disassembly from a cost factor to a profit generating activity (Duflou et al., 2006;Willems et al., 2005).. ...
Prior research has demonstrated that a disassembly based end-of-life (EoL) treatment for electronic products is characterized by the highest recovery rates for precious metals (PMs) and non-commodity plastics, such as flame retardant plastics. Nonetheless, EoL electronic products are nowadays also commonly recycled without disassembly in different types of size-reduction based treatments or in an integrated PM smelter-refinery. This disparity of recycling processes adopted worldwide resulted in a high uncertainty on the EoL treatment processes that will be adopted for discarded electronic products. As a result, governments, original equipment manufacturers and recycling companies struggle to determine the economic and environmental value of design for disassembly. For this reason, a methodology is presented to calculate the Composite Rate of Return (CRR) on investing in design for disassembly and the resulting environmental impacts. This methodology is applied to evaluate the economic and environmental benefits of implementing three types of active fasteners for eleven electronic products which are available in both a product service system (PSS) and a traditional sales oriented business model. The performed analyses demonstrate that the preferred EoL treatment, as well as the economic and environmental benefits of implementing design for active disassembly, strongly depends on several product properties and boundary conditions. Based on the performed sensitivity analysis, the application of active pressure and temperature sensitive fasteners is expected to be only economically viable for products placed on the market in a PSS context, in which they will be separately collected with a high collection rate. Furthermore, impulse sensitive elastomer based fasteners are characterized with the highest rate of return and considered to be suited for both products sold in a traditional sales oriented business model and for products used in a PSS.
... Furthermore, disassembly processes also involve technological issues, which might affect the costs and the recovery process (Ueda et al., 2005). A study by Willems et al. (2005) also highlighted that disassembly might seamless attractive since the process itself, may, at times, not be economically feasible, which could result in a low intention of incorporating DfD in the design practice. ...
Design for Environment (DfE) and Design for Disassembly (DfD) have been recognized as an effective sustainable manufacturing approach to reduce environmental impact during product's life cycle. Although Malaysian manufacturers have long demonstrated a strong global market presence, the implementation of DfE and DfD among manufacturers are found lacking. This paper attempts to investigate the current state DfE and DfD implementation and the local driving force in the local Malaysian industry by addressing four research questions (RQ): RQ1 - How do Malaysian designers value the importance of DfE? RQ2 - What are the current approaches used by designers to incorporate environmental issues during product development stage? RQ3 - What difficulties are experienced in the implementation of DfE and DfD in the product development stage? RQ4 - What are the approaches needed to enhance the engagement of DfE and DfD into product design practices? Targeting product designers in Malaysia, a multiple approach using survey and interview is conducted shown that the current state of implementation and awareness within the local industry is fairly low. The soft approach of the local legislation does not contribute much towards seeing a major change in attitude as will be discussed further in the paper. The above two concerns are major challenges that require immediate attention. However, there seems to be growing concern from the industry and the government that pushes the need for options that could leapfrog the current situation. This presents an opportunity for the local research community to come up with various strategies that will be discussed. Finally, the paper proposes a more comprehensive strategy that is tailored to the local business environment in order for the local industry to be capable of maintaining its market presence.
... Many efforts have been done in the field of Design For Recycling and Disassembly (DFR or DFD). A promising DFD concept to make disassembly economically feasible is Active Disassembly (AD) [19]. Products designed for AD are products that contain connections for which a specific external trigger or a combination of triggers can initiate a simultaneous unfastening process [13,20]. ...
To accomplish a Cradle to Cradle approach, which implies closing the material loop and avoiding downcycling, it is imperative to improve the physical separation processes. Therefore, a holistic life cycle approach, in which different actors in the lifecycle are involved, is required to allow the exchange of key information. This study describes a generic structure for a relational database that allows the required product information to be exchanged between manufacturer and recyclers, as well as the possible benefits for these companies to have this information available. The further goal of this database is to enable an evaluation and optimization from an economic and environmental point of view of the product design and alternative end of life treatment scenarios.
... One such element that falls in this category is the pressure triggered snap, which was analyzed by Katholieke Universiteit Leuven in Belgium [10][11][12]. Katholieke Universiteit Leuven has also conceptually analyzed a number of other AD elements including: freezing elements, pneumoelements, soluble elements, and hydrogen storage alloy elements [13,14]. ...
This paper explores a means to control the active disassembly (AD) process for designed and manufactured heat-activated shape memory polymer snap-fits. Testing was performed for demonstration of the active release of the SMP snap-fits and for analysis of AD control factors. Robust design methodologies with Taguchi methods were used to analyze the AD process factors, including heating method and disassembly temperature. The results from this research show the successful demonstration of the SMP snap-fits. AD process analysis shows that both the heating method and temperature affect the AD process. The analysis determines that by increasing the heat exchange rate the snap-fit disassembly time is shortened. From the performed experiments, it was seen that an Oil bath at 150°C produced the best results in regards to disassembly time and signal-noise ratio.
... mechanical, thermal, chemical, etc.) and cause the product to disassemble. Conceptual designs for DED have shown efficiency improvements with disassembly processes, but due to their specialization per product, intense work in the design stage is needed, which limits DED's flexibility and use (Willems et al., 2005). In an effort to reduce this design work and increase flexibility, AD has resulted. ...
The paper put forward to active disassembly, multi-step active disassembly methods and design criteria based on electro and heat stimulation. General design method of active disassembly product based on electro and heat stimulation was explained through the case analysis. Finite element analysis results are compared with experimental ones, electro and heat stimulation experiments were compared with the traditional heat stimulation experiments, and then the feasibility of method was proved. Active disassembly method and the design criterion were used in active disassembly design of products, disassembly efficiency for products are improved obviously.
Shape memory materials were used as active disassembly unit of LCD frame and LCD frame was redesigned by using the method of ADSM. Active disassembly design principles of LCD frame were proposed. A mechanical analysis model of active disassembly unit was established. The layout position of active disassembly unit in the frame was simulated by ABAQUS, and optimal size and layout position of the active disassembly structure were determined. At last, the size, layout position and disassembly effect of active disassembly structure of LCD frame were verified by experiments. A theoretical reference is provided for the design of LCD active disassembly structure.
An important process for the reuse and recycling of end of life products is their disassembly. In general, manual disassembly is a labor intensive and costly process. Especially, removing fasteners takes time and cost. For solving this problem, this paper proposes a design method for the partial dismantling of products with split-lines, which are added to the products at the design phase and enable to destruct the products along the line in order to extract target components. This method supports a designer in determining the location of split-lines by using the geometric model of the product. A case study shows that the dismantling of a LCD TV with split-lines reduces the number of manual operations needed for extracting target components.
Reversible fasteners suited for Active Disassembly (AD), which can be simultaneously released by an increase in ambient air pressure, have been developed in prior research. However, the implementation of these active fasteners in electronic consumer products is hampered as a result of the ongoing trend of miniaturization. Therefore, a second generation of pressure based fasteners was developed in line with the evolutionary TRIZ trends. This paper presents a novel pressure sensitive snap-fit for electronic products which makes use of closed cell elastomer foam and releases at an overpressure of 2 bar.
Active disassembly products often use active disassembly structures triggered by single temperature or pressure field as reversible joints. These structures can be triggered automatically in extreme or accidental circumstances, thus causing the low reliability of products. For improving the reliability of active disassembly products, working mechanisms of active disassembly structure triggered by temperature-pressure coupling is presented in this article. Through analyzing some typical active disassembly structures, this article presents the design criteria and methods of active disassembly structure triggered by temperature-pressure coupling. The feasibility of these design methods is proved by a case analysis. The results of research shows that the reliability of active disassembly structures triggered by temperature-pressure coupling is improved greatly, which can lay the foundation for the industrial applications of active disassembly methods.
DISASSEMBLY is an advantageous end-of-life activity that can promote reuse, remanufacture, and purer recycling of a product's subassemblies and components. The benefit of disassembly for small electronic products, such as modems, routers, and electric adaptors, has, however, outweighed by the processing costs because current disassembly methods require one-at-a-time processing. This limits disassembly for these products and thus limits the recovery of valuable materials and components from these products at end-of-life. Active disassembly (AD) has been a means to overcome this disadvantage by incorporating innovative fasteners and elements that can react with an outside stimulus to cause self disassembly of a product [1]. This in turn will allow for batch or mass processing of products for disassembly. This paper will thus focus on the benefits and efficiency gains in disassembly when products are fitted with AD fasteners. Seven electronic products that would normally not be disassembled at end-of-life are analyzed and their theoretical gains with AD are discussed.
Due to increasing societal awareness, nowadays companies need to consider environmental issues in their business activities. A requirement that has entered the agenda is the design of products to support efficient end‐of‐life management. However, though previous research has addressed various disassembly aspects there is a need for more understanding on which product properties are essential for efficient disassembly processes. Better understanding is also required regarding when, during the product development process, these properties are established. On the basis of empirical studies of disassembly of electrical and electronic equipment and vehicles, this paper suggests a number of product properties that are essential for efficiency of the disassembly process. Furthermore, the paper analyses when these properties are set in the product development process. Four product properties, denoted disassembly properties, have been identified: ease of identification; accessibility; ease of separation; and ease of handling. The analysis shows that these properties are affected during all product development phases. Especially in the early phases it is crucial to consider the disassembly properties in order to avoid unnecessary and costly design changes that may occur in the later development phases if the design solutions are pulled in the wrong direction.
Purpose
The purpose of this paper is to explore how manufacturers can develop automatic end‐of‐life processes facilitated by product design methods, e.g. design for disassembly, recycling and remanufacturing. Also to illustrate this kind of product and end‐of‐life process development while maintaining economic and environmental values. Here, the cases of toner cartridges and liquid crystal displays are the focus.
Design/methodology/approach
The research methodology for this paper began with a literature study within the fields of design for automatic recycling and remanufacturing. It also includes the research performed at two different industrial companies using automation in their end‐of‐life processes. These companies were visited and interviewed several times, in order to understand their processes and what current problems they have in automation and product design.
Findings
Design implications on the end‐of‐life have been explored, and in particular, three general product trends are in conflict with automatic disassembly: products are getting more complex and more heterogeneous; products are getting sleeker; and products are using more proprietary joints. In addition, the three industrial cases describe different problems in industry and how they can be tackled. Although many manufacturers have adapted the design principles of DFM and DFE, there is still much to improve when it comes to designing for the product's end‐of‐life processes. These kinds of adaptations should increase in importance over time as more and more products and components are remanufactured and/or material recycled. These kinds of adaptations will also encourage an increase of products passing through more resource efficient end‐of‐life options.
Practical implications
Manufacturers reading what design problems other companies are experiencing and what solutions can be found would facilitate their own businesses and willingness to start their own and/or improve their existing manufacturing business. This could then be in shape developing products for end‐of‐life processes which also would encourage them to start their own end‐of‐life process facilities.
Social implications
From a societal perspective, an increase in remanufactured products being placed on the market can increase the awareness and confidence of the consumers in non‐new products made from non‐virgin materials. This will increase the market for second‐life products and bring about economics of scale, which in turn will alleviate the problem of depletion of resources.
Originality/value
Most previous research in this area treats the different end‐of‐life processes separately; material recycling and product remanufacturing are but two examples. However, in this paper the focus is more on the overall view of end‐of‐life processes, along with examples of more specific and detailed end‐of‐life processes, such as disassembly and cleaning.
Recent legislative and social pressures have driven manufacturers to consider effective part reuse and material recycling at the end of product life at the design stage. One of the key considerations is to design and use joints that can disengage with minimum labor, part damage, and material contamination. This paper presents a unified method to design a high-stiffness reversible locator-snap system that can disengage nondestructively with localized heat, and its application to external product enclosures of electrical appliances. The design problem is posed as an optimization problem to find the locations, numbers, and orientations of locators and snaps as well as the number, locations, and sizes of heating areas, which realize the release of snaps with minimum heating area and maximum stiffness while satisfying any motion and structural requirements. The screw theory is utilized to precalculate a set of feasible orientations of locators and snaps, which are examined during optimization. The optimization problem is solved using the multiobjective genetic algorithm coupled with the structural and thermal finite element analysis. The method is applied to a two-piece enclosure of a DVD player with a T-shaped mating line. The resulting Pareto-optimal solutions exhibit alternative designs with different trade-offs between the structural stiffness during snap engagement and the area of heating for snap disengagement. Some results require the heating of two areas at the same time, demonstrating the idea of a lock-and-key.
Topology optimization has been extensively considered to design the structural configuration for the stiffness maximization and the eigenfrequency maximization. In this paper, we construct a topology optimization method implementing flexibility with the time-periodic loading condition. First, the flexibility in the dynamic periodic loading is formulated using the mutual energy concept. Second, the multi-optimization problem is formulated using a new multi-objective function in order to obtain an optimal solution incorporating both flexibility and stiffness. Next, the topology optimization procedure is developed using the homogenization design method. Finally, some examples are provided to confirm the optimal design method presented here. Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/41900/1/158-19-1-4_00190004.pdf
The European Union draft Waste Electrical and Electronic Equipment
(WEEE) directive calls for the removal and separate treatment of liquid
crystal displays (LCD). This aspect of the legislation will potentially
have an important impact upon the future `End of Life' (EoL) processing
of much WEEE. Active Disassembly using Smart Materials (ADSM) has been
proven to have applicability in self-dismantling, nondestructive and
rapid disassembly of small electronic products. This paper investigates
the technical feasibility of removing LCD screens from IT communication
products using ASDM technology. In this paper an option is suggested to
cleanly separate LCD screens from printed circuit boards, utilizing an
LCD bracket made from `shape memory polymer'. The case study products
employed are Nokia Japanese J-Phones. Demonstration experiments with
initial results are presented, and future developments discussed. SMB
glass transformation temperatures (Tg) and time efficiency in
disassembly are considered
Active disassembly using smart materials is a concept developed at Brunel University for the design of assemblies with the built-in capability for easy separation of components for recycling on exposure to certain triggering conditions. Such assemblies incorporate shape memory alloy (SMA) actuators in the product housings. These actuators in the form of clips can undergo a shape change (shape memory effect) on going above a transition temperature, and exert a force to effect disassembly. Hitherto, such a change in temperature has been effected by direct heat input external to the assembly. It is now shown in the case of assemblies that contain battery power sources, firstly, that disassembly can be achieved using the residual electrical energy in waste batteries to heat the SMA actuator electrically and, secondly, that there is enough energy left in end-of-life batteries of mobile phones and end-of-life vehicles to trigger at least 4 and 16 devices respectively.
The aim of the work was to demonstrate an alternative to conventional end-of-life (EOL) disassembly strategies such as robotic or hand dismantling. This initial investigation reports the disassembly of consumer electronic products using smart materials in the design of embedded releasable fasteners. A series of products was tested in a variety of different ways using shape memory polymers (SMPs). Tests were run on macroassemblies and subassemblies of telecommunications goods. The devices designed with SMP used two distinct properties of the material suited to active disassembly:
the mechanical property loss (MPL), in this case a loss of rigidity in the thread of the SMP screws; the shape memory effect (SME), a change in form, resulting in this case in the loss of moulded thread from SMP shape memory effect screws.
Once SMP components were developed and embedded into the candidate products, timed disassembly experiments were conducted. These tests used infrared, air jet and water bath methods for applying heat to trigger the SMP devices. Once the trigger temperature was reached, shape change and property loss occurred in the screws and brackets, allowing assembly release.
From an economic point of view the productivity associated with commonly available disassembly methods today seldom makes
disassembly the preferred end-of-life solution for massive take back product streams. In consequence systematic reuse of parts
or components, or recycling of pure material fractions are normally not achievable. Economic models demonstrate that the efficiency
of disassembly operations should be increased an order of magnitude to assure the competitiveness of ecologically preferred,
disassembly oriented end-of-life scenarios. Using fully automated disassembly techniques does not allow to overcome this efficiency
gap if not combined with innovative reversible joints. Enhanced disassembly principles, in which external trigger signals
allow to simultaneously reverse the action of multiple fasteners, forms a promising approach to low cost mass disassembly.
In this paper a state-of-the-art of these emerging techniques is sketched, categorising the fasteners according to their generic
applicability and the degree of imbedded automation of the triggerable disassembly activity. A number of perspectives for
innovative reversible fasteners are sketched as a contribution to this promising paradigm of selfdisassembling products.
Incoming environmental legislation is expected to impose recycling activities on industrial and consumer product manufacturers. Disassembly of used products is needed in order to make recycling economically viable in the current state of the art of reprocessing technology, thus avoiding the future high disposal costs. This paper gives an overview of disassembly research at universities, research centers and industrial companies, pointing out ongoing topics and trends for future activities. Among them, major attention has been paid to basic technological development, product design (design for disassembly), process design (selection of disassembly strategy and automation level) and system design (configuration of manual and automated disassembly facilities, design of disassembly tools). It is also shown how the emerging life cycle concept can be fully exploited to develop suitable ways of dealing with information related to environmental protection and resource optimization. A result of the survey is that further development on disassembly of existing products (technology, planning at process and system level) is needed to allow future products to be designed with recycling considerations in mind.
A review is made of design for assembly (DFA) methods developed over the last fifteen years. It is found that implementation of DFA at the early conceptual stage of design has led to enormous benefits including simplification of products, lower assembly and manufacturing costs, reduced overheads, improved quality and reduced time to market. DFA is now being broadened to include consideration of the difficulty of manufacture of the individual parts to be assembled and is providing the necessary basis for teamwork and simultaneous engineering.More recently, environmental concerns are requiring that disassembly for service and recycling be considered during product design - in fact, total life cycle costs for a product are becoming an essential part of simultaneous engineering. This keynote paper concludes with a discussion of current developments of design for disassembly (DFD).
This paper reports the preliminary to current development of Shape Memory Alloy (SMA) actuators within their application in ‘Active Disassembly using Smart Materials’ (ADSM). This non-destructive self-dismantling process is to aid recycling of consumer electronic products. Actuators were placed in single and multi-stage hierarchical temperature regimes after being embedded into macro and sub-assemblies of electronic product assemblies. Findings include active disassembly and a hierarchical dismantling regime for product dismantling using developed SMA actuators embedded into candidate products.
Dresden, Techn. Universiẗat, Diss., 2000.
In the fiscal year of 2000 through 2002, we were engaged in the study of auto-disassembly systems using shape memory materials as a theme of study commissioned by MSTC (Manufacturing Science and Technology Center), one of the extra-governmental organizations of MITI (Ministry of Economy, Trade and Industry). The goal of the theme was to report the results of the study to MITI (MSTC) and release developed technologies to the public. In February 2003, we made a demonstration of aggressive disassembly models for disassembly by heating in the factory of Riken Hatsujo Kogyo Co., Ltd. (a spring manufacturer in Osaka), inviting representatives of other companies and university personnel concerned. In this paper, we introduce the results of the study along with our outlook for the future.
Current joining technology especially used for electronic
products, such as soldering, wire bonding, thermo-compression bonding,
adhesive bonding, are not used to be designed for dismantling, even
though rework or repair is indispensable in practical applications. In
this paper, the concept of active disassembly and reversible
interconnection is critically reviewed by considering the bonding and
debonding mechanism of the materials interfaces. Disassembly process is
characterized both by disassembly energy and disassembly entropy. Active
disassembly is defined as such disassembly operations using an active
mechanism which is built-in to the assembly macroscopically or
microscopically, or even in the material itself to reduce the necessary
energy and/or entropy for disassembly. The reversible interconnection is
a concept for interconnection method which enables the products to be
assembled and disassembled reversibly. Active assembly can be used for
realizing a reversible interconnection. Several new attempts to develop
a method for reversible interconnection are presented. The bonded
interface is weakened by segregation of alloying elements, or by
hydridation of hydrogen storage alloy used as bonding intermediate which
becomes very brittle or pulverized by absorbing hydrogen. Also,
selectivity of disassembly can be achieved by using temperature
dependence of the phenomena of hydrogen absorption. Examples are shown
to demonstrate how the concept is applied to electronic products or
dismantling PWB assemblies
This paper reports results the application of shape memory polymer
(SMP) technology to the active disassembly of modern mobile phones. The
smart material SMP of polyurethane (PU) composition was employed. Two
different types of SMP fasteners were created for these experiments.
With these smart material devices, it is possible for products to
disassemble themselves at specific triggering temperatures at EoL. The
two designs were compared for disassembly effectiveness. The disassembly
technique is termed active disassembly using smart materials (ADSM), and
has been successfully demonstrated on a variety of mobile phones. Whilst
developed primarily as a universal disassembly technique, cost
effectiveness and time performance is apparent. Heat sources of +90,
+100 and a range of +67 to +120°C were employed to raise the
releasable fasteners above their trigger temperatures: in the case of
SMP this would be the glass transition temperature (Tg). The development
of releasable fasteners and applications in electronic products is
described
This paper surveys end-of-life strategies currently used in the
electronics and appliances industries and identifies product
characteristics that define feasible end-of-life strategies. The
authors' survey indicates that two key characteristics serve as factors
to categorize appropriate products' end-of-life path: product life and
technology cycle. The categorization leads to a methodology that guides
product developers to specify, end-of-life strategies, to seek
environmentally friendly designs, and to identify opportunities for
developing new recycling technologies. The goal of disassembly differs
depending an each product category, however, efficient disassembly is a
key to carry out the ideal end-of-life strategies for every product
category. To enhance disassemblability, the authors propose the concept
of the product embedded disassembly process. The fundamental idea is to
embed a separation feature inside a product during manufacturing and
activate it at disassembly
Disassembly is a fundamental process needed for component reuse and material recycling in all assembled products. Integral attachments, also known as "snap" fits, are favored fastening means in design for assembly (DFA) methodologies, but not necessarily a favored choice for design for disassembly. In this paper, several protorype designs of a new class of integral attachments are presented, where the snapped joints can be disengaged by the application of localized heat sources. The design problem of reversible integral attachments is posed as the optimization of compliant mechanisms actuated with localized thermal expansion of materials. The Homogenization Design Method is utilized to obtain an optimal structural topology that realizes a desired deformation of snapped featuers for joint release. The obtained optimal topologies are simplified to emhance the manufacturability for the conventional injection molding technologies. Results of the example designes are verified by finite element analyses.
Systematic development of easy-to-unlock connections and a flexible unlocking tool
- J Klett
- S Cosiglio
- L Blessing
- G Seliger
Klett J., Cosiglio S., Blessing L., Seliger G., Systematic development of easy-to-unlock connections and a flexible unlocking tool, Proceedings of the Global conference on sustainable product development and life cycle engineering, September, 2004, pp.965-968.
Automatic Disassembly of snap-in joints in electromechanical devices
- A Braunschweig
Braunschweig A., September 23-25, 2004, Automatic Disassembly of snap-in joints in electromechanical devices, Proceedings of the 4th International Congress Mechanical Engineering Technologies '04.
Selection and modification of connections
- J Klett
- L Blessing
Klett J., Blessing L., Selection and modification of connections, Proceedings of the 8th International Design Conference, Dubrovnik, Croatia, May 17-20, 2004, pp.1283-1288.
Flexible disassembly with industrial robots, Paper sent from IPA
- M Kahmeyer
Kahmeyer M., Flexible disassembly with industrial robots, Paper sent from IPA, Stuttgard, 1991. ISEE 2005 134 0-7803-8910-7/05/$20.00 © 2005 IEEE