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Active Disassembly using Shape Memory Polymers for the mobile phone industry
Abstract
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
... 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]. Both the use of thermally triggered Shape Memory Alloys (SMA) and Shape Memory Polymers (SMP) for the concept of AD have been thoroughly investigated in prior research [43,44,47,[50][51][52][53][54][55]. ...
... The most extensive research on active disassembly yet is based on shape memory materials [43][44][45][46][47][48][49]. Both the use of thermally triggered Shape Memory Alloys (SMA) and Shape Memory Polymers (SMP) for the concept of AD have been thoroughly investigated in prior research [43,44,47,[50][51][52][53][54][55]. SMM materials are able to return to an initial shape when heated above the trigger temperature. ...
... This comparison allows indicating the trigger range that can be used for AD for the purpose of repair, remanufacturing or reconditioning, while avoiding unwanted disassembly during the distribution and the use phase. Significant part of the research on AD yet is based on shape memory materials, which are able to return to an initial shape when heated above the trigger temperature [43,44,47,48,53,54]. One case of industrial implementation, albeit discontinued, concerns shape memory alloy (SMA) fasteners in a Sharp mobile phone charger, named 'Easy Release Technology' [7,8]. ...
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.
... One good idea is self-disassembly which is called active disassembly using smart materials (ADSM). Chiodo [29] reported 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 in the experiments . ...
... This method provides a potential dismantling scenario for the removal of all components if this material was to be developed for surface mount components. Research into using ADSM in other small electronics also has been done to handle units such as telephones , cell phones, PCB/component assemblies, cameras, battery chargers, photocopier cartridges, CRTs, computer casings, mice, keyboards, game machines and stereo equipment [29]. ...
Effects of additions minor contents of 0.03% Sc and 0.12% Zr and solution treatment on microstructure and mechanical properties of Al-9.0Zn-2.8Mg-2.5Cu alloy were studied by metallographic microscopy, differential thermal analysis (DSC) and transmission electron microscopy (TEM), in order to obtain high-performance Al alloys. The minor additions of Sc (less than 0.1%) were carried out. The results show that with the additions of 0.03% Sc and 0.12% Zr, the petaloid Al-3(Sc,Zr) precipitated phases occur in Al-9.0Zn-2.8Mg-2.5Cu alloy, and Al-3(Sc,Zr) particles obviously hinder the recrystallization of Al-9.0Zn-2.8Mg-2.5Cu alloy during homogenizing and extruding processes due to their strong pinning effect on dislocation. Multi-stage solution is better than single solution, for it can avoid recrystallization of Al-9.0Zn-2.8Mg-2.5Cu alloy with the minor contents of Sc (less than 0.1%). The proper solution treatment is (420 degrees C, 3 h)+(465 degrees C, 2 h) under which Al-9.0Zn-2.8Mg-2.5Cu-0.12Zr-0.03Sc alloy obtains a tensile strength of 777.29 MPa and a elongation of 11.84%.
... One good idea is self-disassembly, which is called active disassembly using smart materials (ADSM). Chiodo et al. (1999) reported 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 in the experiments. ...
... This method provides a potential dismantling scenario for the removal of all components if this material was to be developed for surface mount components. Research into using ADSM in other small electronics has also been made to handle units, such as telephones, cell phones, PCB component assemblies, cameras, battery chargers, photocopier cartridges, CRTs, computer casings, mice, keyboards, game machines, and stereo equipment (Chiodo et al. 1999). ...
Waste from electrical and electronic equipment (WEEE) constitutes one of the most complicated solid waste streams, in terms of its composition, and, as a result, it is difficult to be effectively managed. Waste from electrical and electronic equipment recycling is an important subject not only from the point of waste management, but also from the recovery of valuable materials. Characterization of this waste stream is of paramount importance for developing a cost-effective and environmentally friendly recycling system. Selective disassembly, targeting on singling out hazardous and (or) valuable components, is an indispensable process in the practice of WEEE recycling. It is very costly to perform manual dismantling of those products, due to the fact that brown goods contain very low-grade precious metals and copper. This work focuses on two major types of WEEE, television sets and refrigerators, giving analytical information on specific recovery and recycling procedures for their effective management.
... One good idea is self-disassembly which is called active disassembly using smart materials (ADSM). Chiodo [29] reported 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 in the experiments . ...
... This method provides a potential dismantling scenario for the removal of all components if this material was to be developed for surface mount components. Research into using ADSM in other small electronics also has been done to handle units such as telephones , cell phones, PCB/component assemblies, cameras, battery chargers, photocopier cartridges, CRTs, computer casings, mice, keyboards, game machines and stereo equipment [29]. ...
ABSTRACT Consumer electronic equipment (brown goods), such as television sets, radio sets, and video recorders, are most common. However, recycling of consumer electronic scrap is only beginning. Characterization of TV scrap was carried out by using a variety of methods, such as
... One good idea is self-disassembly which is called active disassembly using smart materials (ADSM). Chiodo [29] reported 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 in the experiments . ...
... This method provides a potential dismantling scenario for the removal of all components if this material was to be developed for surface mount components. Research into using ADSM in other small electronics also has been done to handle units such as telephones , cell phones, PCB/component assemblies, cameras, battery chargers, photocopier cartridges, CRTs, computer casings, mice, keyboards, game machines and stereo equipment [29]. ...
The production of electric and electronic equipment (EEE) is one of the fastest growing areas. This development has resulted in an increase of waste electric and electronic equipment (WEEE). In view of the environmental problems involved in the management of WEEE, many counties and organizations have drafted national legislation to improve the reuse, recycling and other forms of recovery of such wastes so as to reduce disposal. Recycling of WEEE is an important subject not only from the point of waste treatment but also from the recovery of valuable materials.
... An alternative is active mobile phone disassembly using smart materials, which involves building components using polyurethane based shape memory polymers (SMPs). Through the induction of an external stimulus (trigger) such as temperature, SMPs can return from a deformed state to their original permanent structure, dismantling a minimally altered mobile phone within 1.5 s (Chiodo et al., 1999). This method has potential for low-cost self-dismantling of product housings without any destruction to the host product, but is applicable only when the components are made of SMPs. ...
Due to the vast consumption and shortened lifespan of mobile phones, waste mobile phones (WMPs) have become one of the fastest-growing global waste electrical and electronic equipment (WEEE) streams. Although the recycling potential of WMPs is well-recognized, the current recycling rate remains low, jeopardizing the sustainability of both the environment and mobile phone industries. With the objective of identifying limitations in the current method developments that hinder WMP recycling, we review the material recovering technologies for WMP recycling, published in academic journals and/or conferences between Jan 2005 and Feb 2019. Most WMP recycling processes have been developed to recover precious metals (such as gold and silver) from mobile phone printed circuit boards (PCBs), via acid leaching processes. However, pre-treatment and separation steps required to concentrate the waste stream for efficient extraction are often overlooked. In addition, to separate the individual components of the WMP, most recycling methods use manual disassembly as their first step, a practice which is not suitable for scale-up. Generally, particle size ranges used in laboratory trials are smaller than those used in current industrial practice, as it is not economically feasible to acquire such small particle sizes industrially. There is a current trend to replace the inorganic acids used for metal leaching with more environmentally-friendlier lixiviants, however, industrialization of these approaches is not economically viable. This review serves as a guidance for future research and development in this area, providing information to facilitate WMP management.
... Throughout the six weeks of the summer that this program lasted, I was working on a research project titled "Study of the behavior of Shape Memory Polymers in the Active Disassembly Process" under the supervision of Dr. Hua Li. This project focused on active disassembly using smart materials (ADSM) as an alternative, with the potential to enable a broad range of electronic devices to be actively disassembled at the same time, reducing the cost of the manual labor or machine operation needed to disassemble the products [1][2][3][4][5] . One of the main aspects of this project that excited and motivated me the most was to be working with smart materials such as Shape Memory Polymers 6 (SMPs). ...
... [1][2][3] Since 1990s, active disassembly, as a non-destructive, low-cost and environment-friendly dismantling technique, has been widely researched, and applied to a variety of small-sized electrical and electronic products. [4][5][6][7][8][9][10][11][12] However, present researches almost focus on the active disassembly in single physical field, especially in temperature field. These methods can achieve disassembly easily, but hardly guarantee that products will not be accidentally triggered during normal use. ...
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.
... The SMP MPL screws are like regular screws upon assembly and use, but at disassembly, when heated, will lose their threading and release from the product. Incorporation of these screws has been seen in Chiodo et al. [10], where Nokia 6110 and Nokia Populus cell phones were retrofitted and disassembled by the screws. Chiodo et al. [11] also used these screws in a retrofitted game controller, clock radio, and CD player for disassembly. ...
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.
... Disassembly is required in order to recycle different parts with high efficiency. The SME based disassembly, i.e., active disassembly [70][71][72][73], provides an alternative to replace manual disassembly. The multiple-SME of engineering polymers, such as PMMA and acrylonitrile butadiene styrene (ABS)/PC, enables us for programmed active disassembly [41,74]. ...
This paper provides a brief review on the advanced shape memory technology (ASMT) with a focus on polymeric materials. In addition to introducing the concept and fundamentals of the ASMT, the potential applications of the ASMT either alone or integrated with an existing mature technique (such as, 3D printing, quick response (QR) code, lenticular lens) and phenomena (e.g., wrinkling and stress-enhanced swelling effect) in product design, manufacturing, and recycling are demonstrated. It is concluded that the ASMT is indeed able to provide a range of powerful approaches to reshape part of the life cycle or the whole life cycle of products.
... TRIZ, a problemsolving, analysis and forecasting tool derived from the study of patterns of inventions in the global patent literature, contains different interesting trends which can be related to the evolution of fasteners and electronic products, such as [19]: -Smart materials: from passive to fully adaptive fasteners, e.g. made out of shape memory materials. The most advanced research on active disassembly yet is based on materials which are able to return to an initial shape when heated above the trigger temperature [20][21][22][23][24][25]. -Object segmentation: from monolithic solid fasteners to a segmented solid up to a vacuum to hold an assembly together. ...
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.
... The Cleaner Research group at Brunel University initiated a set of research using the shape memory alloy (SMA), where SMA showed great recovery force [4][5][6]. Later, they tested strain based shape memory polymers (SMPs), which did not generate large recovery force and were more suitable for fastening design [7,8]. Their first AD element with SMPs is a compression sleeve used in bolt followed by SMP screws designed for electronic products. ...
With the increasing environmental requirements for recycling technologies at the end of product lifecycle, active disassembly is becoming more and more important especially for electric and electronic product recycling. Active disassembly using smart material (ADSM) has been studied in the past decade. However, ADSM have not been widely applied due to the cost, material properties, and limited supply. Shape memory polymer (SMP) actuated hollow snap-fit may become one of the possible alternatives in ADSM, which will reduce the usage of smart materials and increase the mechanical properties of snap-fit. This research is aimed to fully investigate the SMP-actuated hollow snap-fit design and propose some guidelines for its future implementation. The correlation between design parameters and two major design objectives, maximum deflection and mating force, were analyzed using FEA software. Furthermore, an approach to search the optimal design values for given design requirements was presented. In order to maximize the recovery force generated by SMP in active disassembly process, an investigation of magnifying the deformation stress by engineering actuator’s shape design was completed. The methods and conclusion presented in this paper could be used as reference for hollow snap-fit development and application.
... This called for the use of strategically placed biasing springs which will force the electronic device open when the screws lose their threading. These MPL screws were used to disassemble many electronic devices including: cell phones, electronic game controllers, clock radios, and CD players [17][18] . The regular SME with SMP has shown that active disassembly of separating LCDs from its housing is possible. ...
... Their first studies used SMA alloy coils and rods that would forcefully open and separate a product's components upon a thermal trigger12345. Their AD studies with SMPs have used manufactured screws that lose their threading upon a thermal trigger and LCD brackets that will release a LCD upon a thermal trigger6789. ...
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.
... There is variability due to the added housing, which can impede the heat transfer to the SMP snap-fit and thus increase the time for recovery. This is particularly evident in comparison to other SMP shape recovery tests, where the recovery was seen in a matter of seconds (Chiodo et al., 1999a,b). Even with such an impediment on the shape recovery time with the SMP snap-fits, the actual AD process can be altered by batching products together for disassembly. ...
... their threading and release from the product. Incorporation of these screws has been done in a number of AD studies for electronic products [5]. Beyond SMP compression sleeves and SMP MPL screws, there have been original designs for product assemblies that incorporate SMP elements without retrofitting, such as an LCD bracket that will release upon a thermal trigger [6]. ...
An active disassembly (AD) shape memory polymer nanocomposite (SMPN) fastener that is released by application of a thermal and magnetic field has been developed. Provided is key data on the behavior of the fastener at specific temperature ranges and magnetic field strengths for exhibiting proper levels for disassembly. Furthermore, a comparison of this fastener to a previous shape memory polymer (SMP) fastener shows differences in the thermal shape memory ability of the SMP fastener and the thermal-magnetic ability of the SMPN fastener. The SMPN fastener is an option for disassembly and exhibits added control parameters to single trigger AD fasteners.
... cts only have limited effects on the reduction of their environmental impact and has almost no effect on the improvement of recyclability that, as an inherent feature of a product, is determined during product development phases. Design strategies and configurations play decisive roles in moulding the ease-ofrecycling nature of a product (Ishii et al. 1994; Kobayashi et at. 1999). ...
This paper presents a methodically structured design model for achieving a comprehensive improvement of product recyclability.
The framework of this model consists of four design phases, integrating the prediction of product end-of-life strategy, the
formation of modular structure, the selection of materials and fasteners, and the recyclability evaluation of design alternatives.
The four phases are hierarchically organised in the body of the framework for a stepwise implementation, which are corresponding
to the processes of generic engineering design at the stages of planning and task clarification, conceptual design and embodiment
design. Fuzzy sets and graph theory are jointly applied as the basic techniques to formulate the methods for end-of-life strategy
planning and structure modularisation. An air-conditioning system is used as an example to demonstrate the application of
the proposed design model and its effectiveness in improving the recyclability of a product.
... Chiodo et al. [9][10][11][12] and Arnaiz et al. [2] applied this technology for the disassembly of a range of products, among which different types of telephones. These products were designed with shape memory snap fits. ...
The productivity associated with commonly available disassembly methods today seldomly makes disassembly the preferred end-of-life solution for massive take back product streams. Systematic reuse of parts or components, or recycling of pure material fractions are often not achievable in an economically sustainable way. In this paper a case-based review of current disassembly practices is used to analyse the factors influencing disassembly feasibility. Data mining techniques were used to identify major factors influencing the profitability of disassembly operations. Case characteristics such as involvement of the product manufacturer in the end-of-life treatment and continuous ownership are some of the important dimensions. 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 for large waste of electric and electronic equipment (WEEE) streams. Technological means available to increase the productivity of the disassembly operations are summarized. Automated disassembly techniques can contribute to the robustness of the process, but do not allow to overcome the efficiency gap if not combined with appropriate product design measures. Innovative, reversible joints, collectively activated by external trigger signals, form a promising approach to low cost, mass disassembly in this context. A short overview of the state-of-the-art in the development of such self-disassembling joints is included.
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.
This paper reports on a research experience for a teacher in researching the behavior of shape memory polymers. The use of active disassembly using smart materials (ADSM) can be an alternative, with the potential to enable a broad range of electronic devices to be actively disassembled at the same time, reducing the cost of the manual labor or machine operation needed to disassemble the products. Shape memory polymers (SMP) are promising materials for this application. The main aim of the present study was to create SMP snap-fits and analyze the effect design parameters on the disassemble time. Six sets of snap-fits with different design parameters were manufactured form a commercial SMP Veritex. They were tested and the disassemble time was analyzed. According to the results, design parameters showed to have a slight influence in the disassemble time during the active disassemble process. A learning module based on the legacy cycle concept is being developed and it challenges students to think through new applications for the shape memory polymers. This learning module will be introduced into a high school mathematics class during the 2011-2012 school year. Assessment of the student's performance will be carried out and reported.
ADSM is based on active disassembly devices which are made of smart materials such as shape memory materials. When the active disassembly devices are triggered and invalidated, the parts connected by them will be detached. The most widely used active disassembly devices are made of SMP. The detachment effects of SMP active disassembly devices include the time of shape restoring and the active disassembly rate. They are influenced by factors like the material variety and the maximum shape restoring of active disassembly devices, the temperature and means of heating in active disassembly process, etc. The influences of these factors were researched by experiments, and the methods to enhance detachment effects of SMP active disassembly devices were put forward.
It is difficult to disassemble the complicated or big product completely, it is also difficult to choose the components if they are mixed together. One of the solutions is multi-step active disassembly. This paper mainly studied a method of multi-step active disassembly, discussed the theory, and analyzed the design principles of multi-step active disassembly products. Finally, the feasibility of multi-step active disassembly was proven by using actual example.
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.
Purpose
The purpose of this paper is to investigate the effects of different shape memory polymer based snap‐fits in terms of disassembly time and reusability.
Design/methodology/approach
In total, six different sets of snap‐fits were designed and manufactured. Each set of snap‐fits was tested ten times in a testing device for disassembly time. The stress caused by training process is simulated and analyzed.
Findings
One of the designs shows shortest average disassembly time, lowest standard deviation, and lowest stress. However, the overall reusability of the snap‐fits is not good enough for industrial use.
Originality/value
The paper tests the Veritex shape memory polymer sheets manufactured by CRG Industries LLC. The reusability has been analyzed based on the stress caused by the training process.
In this article, we present a brief review about polymeric shape memory materials (SMMs) and typical applications of these materials for functioning as actuators. A couple of generic working mechanisms to enable the shape memory effect (SME) in materials are introduced, together with some relatively new shape memory phenomena, such as the multiple-SME, temperature memory effect (TME), mechano-responsive SME, etc. It is revealed that now we are able to not only design/syntheses a polymeric material, but also to tailor its performance to well meet the requirement(s) of a particular application. It is concluded that the shape memory technology (SMT) provides us a powerful tool to produce far greater impact to reshape both product design and fabrication.
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.
This paper focuses on product modelling and a decision-support system for product design and manufacture within which product end-of-life (EOL) issues can be addressed and quantitatively evaluated. A framework method is developed to determine good design and manufacturing strategies enabling products to meet quality and functionality criteria with minimum environmental impact and life-cycle costs. The assessment of alternative scenarios involves the consideration of several qualitative and quantitative factors simultaneously, and therefore has to be handled by multi-attribute analysis techniques.
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.
This paper focuses on the applications of poly(methyl methacrylate) (PMMA), one of the most commonly used engineering polymers, for active disassembly (AD). PMMA was first characterized by a series of thermo-mechanical tests to find the suitable programming temperatures and its shape memory characteristics. Four releasable fasteners were then developed, and tested, i.e. active screw, active joint, active snap-fit and active tab. It was successfully demonstrated that PMMA is a promising candidate for AD. Moreover, programmed AD has been achieved as well through a series of temperature-activated actions during the disassembly process. These techniques are applicable to other engineering polymers for AD and programmed AD.
Due to the characteristic that shape memory materials can quickly return to their original shape and have large deformation, such materials can be used as the connection in active disassembly devices. However, existing active disassembly devices typically require two moulding steps and complicated machining processes that result in high manufacturing cost. The active disassembly device based on the proposed decapitated head method has only one moulding step and lower manufacturing cost. Its disassembly mode is local damage disassembly, which can decrease the active disassembly cost and improve disassembly efficiency. This paper describes the active disassembly theory and the design methodology based on the decapitated head method, and then analyses the design criteria and feasibility of this method with a real case study.
Disassembly has been widely accepted as a disadvantageous end-of-life activity, but with increasing pressures from directives, such as waste on electrical and electronic equipment, and with increasing pressures to become sustainable disassembly is becoming necessary. Current disassembly methods, including both manual and automated disassembly, need improvements to meet this necessity. This paper will introduce the improvements needed and suggest through literature the validity of active disassembly (AD) to provide these improvements. Past and current research will also be considered to provide a future path for AD. This future path for AD will consider a collaborative effort to solve problems with materials, environmental triggers and costs seen with AD.
Shape memory polymers (SMPs) are materials that have properties, such as Young's modulus, that change in response to an external stimulus. As such they are one of a number of materials, including shape memory alloys (SMAs) and ceramics, that can be used as adaptive materials in intelligent systems. In this memorandum, the literature pertaining to shape memory polymers is reviewed. Topics covered include the history of the development and commercialization of SMPs, the basis of the shape memory effect in polymers, the advantages and disadvantages of SMPs, applications of SMPs, the description of linear and nonlinear constitutive models proposed for SMPs, and the potential to develop poly(urethane) based SMPs with tailored properties.
It was observed that the polyurethane shape memory polymer (SMP) loses its shape fixing capability after being exposed in the air at room temperature for several days. A significant indication for this change is the continuous decrease of the glass transition temperature (Tg) of polyurethane. Accompanying the decrease of Tg, the uniaxial tensile behaviour also changes. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests were carried out to find the cause behind this phenomenon. Moisture was concluded as the main reason. A mathematical expression was obtained for the relationship between Tg and the moisture. Moreover, the polyurethane shape memory polymer can fully regain its original properties after being heated at temperatures above 180 °C, which is the melting temperature of this SMP.
This paper presents the design of new joints, heat-reversible snaps, which allow easy, non-destructive, and clean detaching between internal frames and external panels in automotive bodies. It is expected to dramatically reduce the end-of-life environmental impacts of the aluminum space frame bodies, which currently suffer from poor material recyclability. While the assembly process is analogous to normal locator-snap systems, the heat-reversible snaps can be unlocked non-destructively upon heating the panel at a certain location, via the non-uniform thermal deformation of the panel. The optimum number and locations of the locators on the given panel are found based on the equivalent springs that represent the stiffness of the locator. Then, the locations of snaps and heating that ensure unlocking upon heating of the minimum area on the panel are obtained. Finally, a case study on an automotive fender panel assembly is discussed. INTRODUCTION Aluminum space frame (Figure 1) is considered as the next generation body structure [1, 2] due to its lightweight, improved rigidity, and design freedom realized by the separation of "bone" and "skin" [3]. They are also environmentally sound since the environmental impact (mainly CO 2 emission) during the use phase of the vehicle is very low due to the improved fuel efficiency (32% of fuel savings) owing to its lightweight (40% lighter than steel body [2]). According to the previous results of life-cycle analyses [1, 4], it is essential to improve the recyclability of aluminum space frame bodies in order to compare with the steel bodies, which currently, have lower energy consumption for production and higher recyclability as a raw material. Figure 1: Audi Space Frame [5].
Active disassembly technology provides the designer a useful unmanned disassembly processes to achieve efficient recycling
for products. Currently, many types of smart active fasteners are developed by using shape memory plastics (SMP). This technology
has been testing in cell phones and LCD TVs to confirm the concepts. This paper presents an eco-innovative design methodology
by using TRIZ method to innovate the new concepts of smart active fasteners for active disassembly at the end-of-life stage
of products. The tools of TRIZ, such as contradiction matrix, inventive principles, and substance-field analysis, are chosen
in this study to develop this eco-innovative design methodology. Examples are demonstrated to illustrate the capability of
proposed methodology.
Active disassembly using smart materials is a relatively new technology. Extensive tests have shown that the technology works.
Analysis of product categories indicates that plastics dominated products as well as precious metals dominated products are
most likely to benefit from including active disassembly in their end-of-life strategies. The economic implications of doing
so are investigated. In principle, active disassembly will turn out much cheaper than conventional disassembly, and will greatly
reduce processing times as well as improve specifications of output fractions. Further testing with respect to determining
the ecological advantage is needed, but it is believed that considerable gains may apply here also.
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.
To make disassembly cost-efficient, one-to-many fasteners are needed. These fasteners use advanced materials or structures as a catalyst for disassembly, allowing multiple assemblies to separate simultaneously after exposure to specific external triggering conditions. Using topology optimization this paper explores a systematic development strategy for structure based one-to-many disassembly concepts
Waste electronic products and equipments are a severe environmental problem in China, because of the massive number of the waste produced everyday. The design for disassembly is an effective way to deal with this problem. This article discussed the principles and general process of disassembly and looked over some effective methods that can be applied in the design for disassembly.
One simple approach to produce electrically conductive polymers is to fill them with conductive powders. This paper investigates the effects of moisture on the glass transition temperature of a polyurethane shape memory polymer (SMP) filled with nano-carbon powders. It is found that the SMP composites before immersion in water have a slightly lower glass transition temperature, and in the mean time, the moisture fraction at the saturation point upon immersion is also lower. On the other hand, the moisture can remarkably reduce the glass transition temperature of the composites. Heating to over 180 °C is an effective way to remove the moisture, which also results in the glass transition temperature back to the original. As the glass transition temperature can be greatly reduced by moisture, a novel feature, namely, the water actutable recovery of SMP composites is also proposed based on this study.
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.
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.
Using topology optimization this paper explores alternative configurations of pressure-based active fasteners. The 2D and 3D optimization problem is solved for a snap-fit like design. A detailed finite element verification is conducted, the theoretical designs are translated into producible components and preliminary concepts how to manufacture the designs are presented.
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.
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
Industrial recycling is a practice of growing importance while
impending `Take Back' European legislation and economic pressures are
increasing. Landfill sites are becoming exhausted and the industry could
benefit from a novel approach to recycling pre and post consumer waste.
Cost constraints limit the number of different products that can be
recycled. Recyclers are working on broadening the range of reusable
components from this waste stream, but the proposed approach would
significantly increase the volume of recyclable material used in
manufacturing new products. This alternative could potentially reduce
recycling cost per product in the event of mandatory recycling as a wide
variety of consumer electronics could be actively or self disassembled
on the same generic dismantling line. The use of Shape Memory Alloy
(SMA) actuators in a wide variety of consumer electronic products in the
same dismantling facility was tested. The candidate products had
undergone a multi-stage hierarchical temperature regime on their macro
and subassembly disassemblies and results reported. Two forms of SMA
actuators were employed in the designs of actuators; these were one-way
Nickel-Titanium (NiTi) and two-way Copper-Zinc-Aluminum (CuZnAl)
actuators
This is a new and up-to-date edition of a standard reference work in which the specialist terms of a wide range of sciences and technologies (including textile technology) are listed and explained. Such a reference work is of increasing importance in a world where the terminology of individual sciences and technologies is met with increasing frequency in other sciences and technologies. A number of appendices contain useful additional information including SI (internationally agreed basic units) conversion factors.
This paper reports initial results in the application of shape
memory polymer (SMP) technology to the active disassembly of electronic
products. The smart material SMP of polyurethane (PU) composition was
employed. Created for these experiments were novel SMP releasable
fasteners, with which it is possible to effectively disassemble products
at specific triggering temperatures at the end of their life (EoL). This
disassembly technique is termed active disassembly using smart materials
(ADSM), and has been successfully demonstrated on a variety of products
using other smart materials. Whilst developed primarily as a universal
disassembly technique, cost effectiveness is apparent. Heat sources of
+70, +100 and +225°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
Applications of Shape Memory Polyurethanes: The First International Conference on Shape Memory and Superelastic Technologies
- R F Gordon
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Active Disassembly using SMART Materials (ADSM), unconventional ideas EPSRC research grant
- E H Billett
E.H. Billett, Active Disassembly using SMART Materials (ADSM), unconventional ideas EPSRC research grant, Brunel University, Runnymede, Surrey, UK, 28 April '96 to 28 April '97.
Larousse Dictionary of Science and Technology' (Edinburgh: Larousse
- P M B Walker
- Ed
Walker, P. M. B. Ed., 'Larousse Dictionary of Science and Technology' (Edinburgh: Larousse, New York Larousse Kingfisher Chamber Inc., 1995), pp. 479 -480.
Development of Polymeric Shape Memory Material', Mitsubishi Technical Bulletin No
- Yoshiki Shirai
- Shunichi Hayashi
Yoshiki Shirai and Shunichi Hayashi, 'Development of Polymeric Shape Memory Material', Mitsubishi Technical Bulletin No. 184 (Nagoya Research & Development Center, Technical Headquarters, Mitsubishi Heavy Industries, Ltd., Nagoya, Japan, 1988), (market availability 1994).
Eco-design for active disassembly using smart materials Shape Memory and Superelastic Technologies (SMST'97) conference, Asilomar Conference Center
- J D Chiodo
Chiodo, J. D. et.al., " Eco-design for active disassembly using smart materials, " Shape Memory and Superelastic Technologies (SMST'97) conference, Asilomar Conference Center, Pacific Grove, CA., USA., 2-6 March 1997.